Title of Invention

A COMPOSITION COMPRISING AN ADHESIVE AND A POLYPEPTIDE

Abstract A composition comprising an adhesive and a polypeptide comprising amino acid sequence LKKTET or a conservation variant thereof such as herein described wherein said adhesive and said polypeptide are covalently bound together.
Full Text COMPOSITIONS AND METHODS FOR DELIVERING THYMOSIN BETA 4,
ANALOGUES, ISOFORMS AND OTHER DERIVATIVES
A COMPOSITION COMPRISING AN ADHESIVE AND A POLYPEPTIDE
BACKGROUND OF THE INVENTION
CROSS-REFERENCE TO RELATED APPLICATION
[001] This application claims the benefit of U.S. Provisional Application No.
60/458,399, filed March 31, 2003.
Field of the Invention
[002] The present invention relates to the field of compositions and methods
for delivering polypeptide pharmaceuticals.
Description of the Background Art;
[003] Polypeptide pharmaceuticals can be extremely efficacious agents in the
treatment of various maladies. Since polypeptide pharmaceuticals can be very
expensive to produce, there is a need in the art for improved compositions and,
methods for delivering polypeptide pharmaceuticals.
SUMMARY OF THE INVENTION
[004] In accordance with the present invention, a composition comprises a
substantially purified composition including an adhesive and a polypeptide
comprising amino acid sequence LKKTET, or a conservative variant thereof. A
method of delivery of a polypeptide to a site comprises introducing the above
composition to the site.

DETAILED DESCRIPTION OF THE INVENTION
[005] The present invention provides compositions and methods utilizing
actin-sequestering peptides such as thymosin p4 (Tβ4) and other actin-
sequestering peptides or peptide fragments containing ammo acid sequence
LKKTET or conservative variants thereof. Included are NB or C -terminal variants
such as KLKKTET and LKKTETQ. These peptides and peptide fragments are
useful in promoting wound healing and other physiological uses.
[006] Thymosin p4 was initially identified as a protein that is up-regulated
during endothelial cell migration and differentiation in vitro. Thymosin β4 is a 43
amino acid, 4.9 kDa ubiquitous polypeptide identified in a variety of tissues.
Several roles have been ascribed to this protein including a role in a endothelial
cell differentiation and migration, T cell differentiation, actin sequestration and
vascularization.
[007] Thymosin β4 is a member of the β-thymosin family of highly conserved
polar 5-kDa polypeptides found in various tissues and cell, types. Originally
purified from thymus and regarded as a thymic hormone, thymosin β4 was then
found to be involved in multiple biological processes. As the main G-actin
sequestering peptide, it plays an important role in regulation of actin assembly
during cell proliferation, migration, and differentiation. Numerous studies
implicate thymosin p4 in regulation of cancerogenesis, inflammation,
angiogenesis, and wound healing. It was found that thymosin β4 expression
regulated tumorigenicity and metastatic activity in malignant cell lines through
actin-based cytoskeletal organization. Thymosin β4 was found to be elevated in
tube forming endothelial cells; it increases their attachment, spreading and
migration thus promoting angiogenesis. Thymosin β4 was also found in ulcer

extracts and wound fluids at high concentrations and was suggested to function
as an antibacterial factor. The stimulating role of thymosin β4 in wound healing
was demonstrated in several studies with animal models. When added topically
or administered intraperitoneally, thymosin β4 enhanced dermal wound healing
in a rat full thickness model. The abiliiy to accelerate dermal wound healing has
also been observed in db/db diabetic mice, steroid-immunosuppressed mice and
in aged mice. Thymosin β4 has also been shown to accelerate healing of the
corneal epithelium after burn injuries and to down regulate a number of corneal
cytokines and chemokines reducing the inflammatory response.
[008] Activation of the coagulation cascade upon vascular injury results in
generation of thrombin which converts fibrinogen into fibrin. Fibrin polymerizes
spontaneously to form blood clots which seals damaged places thus preventing
the loss of blood. Fibrin also serves as a provisional matrix on which various cell
types adhere, migrate and proliferate replacing fibrin with normal tissues during
subsequent wound healing processes. Factor XIIIa, a plasma transglutaminase,
covalently cross-links the fibrin clot reinforcing its structure. In addition, it also
cross-links to fibrin a number of physiologically active proteins which may
modulate properties of the fibrin matrix. For example, covalent incorporation of
α2-antiplasmin increases resistance of the matrix to fibrinolysis and
incorporation of fibronectin may affect its ability to support cell adhesion and
migration. Tissue transglutaminase can selectively incorporate into fibrin
thymosin 04.
[009] Thymosin β4 serves as a specific substrate for tissue transglutaminase
and can be selectively cross-linked by it to collagen, actin, fibrinogen and fibrin,
proteins which are also involved in the above mentioned processes. After


'activation of platelets with thrombin, thymosin β4 is released and cross-linked to
fibrin in a time- and calcium-dependent manner. Platelet factor XIIIa is co-
released from stimulated platelets. Cross-linking of platelet-released thymosin
β4 to fibrin appears to be mediated by factor XIIIa and provides a mechanism to
increase the local concentration of thymosin β4 near sites of clots and tissue
damage, for promotion of wound healing, angiogenesis and inflammatory
response.
[0010] Fibrinogen is a chemical dimer comprising two identical subunits, each
composed of three polypeptide chains, Aα, Bβ and γ held together by a number of
disulfide bonds. The disulfide-linked NH2-tenninal portions of all six chains form
the central E region, while the COOH-terminal portions form two terminal D
regions and two αC-domains. Upon conversion of fibrinogen into fibrin,
thrombin-mediated removal of the NH2-terminal fibrinopeptides A and B from the
fibrinogen and removal of the NH2-terminal fibrinopeptides A and B from the
fibrinogen Aα and Bβ chains, respectively, results in exposure of their active
sequences (polymerization sites) and enables interaction between the E and D
regions of neighboring molecules (DD:E interaction) to form a fibrin polymer. The
polymer becomes cross-linked by factor XIIIa through the COOH-termtnal
portions of the fibrin a and γ chains. The intermolecular cross-finking of the γ
chains of the adjacent D regions occurs rapidly resulting in γ-γ dimers, while
cross-linking between the a polymers (aC-domains) occurs more slowly and
results in formation of α polymers. In addition, the a chains serve for cross-
linking to fibrin of such proteins as fibronectin, α2-antiplasmin, and PAI-2. Thus,
it is tempting to hypothesize that these chains could also be involved in cross-
linking of thymosin β4.

[0011] To clarify the mechanism of the incorporation of thymosin β4 into
fibrin(ogen), its interaction was studied with fibrinogen, fibrin and their
recombinant fragments (domains) in the absence and presence of factor XIIIa.
The study revealed that although there appears to be no substantial non-covalent
interaction between fibrin(ogen) and thymosin β4, factor XIIIa efficiently crosslinks
the latter to both fibrinogen and fibrin and that cross-linking occurs mainly
through the COOH-terminal portion of their αC -domains including residues 392-
610.
[0012] In accordance with one embodiment, a substantially purified
composition is provided which includes an adhesive and a polypeptide
comprising amino acid sequence LKKTET or a conservative variant thereof. In
accordance with one embodiment, the adhesive is capable of adhering to medical
devices such as stents. In a particularly preferred embodiment, the adhesive is
capable of adhering to tissues of a living subject such as a human.
[0013] In preferred embodiments, the adhesive is a biodegradable adhesive.
When used herein, the term biodegradable adhesive is intended to encompass
bioabsorbable or errodable adhesives. In preferred embodiments, the invented
composition initially is in a fluid or semi-fluid state, most preferably in a liquid or
semi-liquid state. In particularly preferred embodiments, after application, the
adhesive increases in viscosity or at least partially solidifies while adhering to the
tissue. The composition may be introduced by applying to an area in a layer,
most preferably by spraying or with a brush.
[0014] In preferred embodiments, the adhesive utilized in the present invention
is a fibrin sealant matrix (fibrin glue). Fibrin glue is a two-component system of
separate solutions of fibrinogen and thrombin/calcium. When the two solutions

are combined, the resultant mixture mimics the final stages of the clotting
cascade to form a fibrin clot. The fibrinogen component can be prepared
extemporaneously from autologous, single-donor, or pooled blood. Fibrin glue is
available in Europe under the brand names Beriplast, Tissel, and Tissucol.
Fibrin glue has been used in a wide variety of surgical procedures to repair, seal,
and attach tissues in a variety of anatomic sites.
[0015] Thus, the present invention provides a method of delivering an LKKTET
polypeptide to a site of a living subject. In preferred embodiments, this site is a
surface. The inventive method comprises applying the inventive composition to
the site. In preferred embodiments, the site is a wound, such as an acute or
chronic wound.
[0016] In preferred embodiments, the adhesive is fibrin, fibrinogen, fibrin glue,
a collagen, fragments of any of the above or a mixture of any of the above.
Collagen adhesives which may be utilized include types 1, 2, 3, 4 and/or 5
collagens. Other adhesives may include actin or integrin adhesives.
[0017] Lα other embodiments, the biodegradable adhesive utilized in the
inventive composition is a gel (e.g., adhesive collagen gel), gel/fibrin mixture,
powder or the like.
[0018] In preferred embodiments, the adhesive is covalently bound to the
LKKTET peptide, most preferably by factor XIIIa. In particularly preferred
embodiments, the adhesive is a fragment of fibrin or fibrinogen.
[0019] In preferred embodiments, the LKKTET polypeptide comprises amino
acid sequence KLKKTET or LKKTETQ, Thymosin 04 (Tβ4), an N-terminal variant
of Tβ4, a C-terminal variant of Tβ4, an isoform of Tβ4, a splice-variant of Tβ4,
oxidized Tβ4, Tβ4 sulfoxide, lymphoid Tβ4, pegylated Tβ4 or any other actin

sequestering or bundling proteins having actin binding domains, or peptide
fragments comprising or consisting essentially of the amino acid sequence
LKKTET or conservative variants thereof. International Application Serial No.
PCT/US99/17282, incorporated herein by reference, discloses isoforms of Tβ4
which may be useful in accordance with the present invention as well as amino
acid sequence LKKTET and conservative variants thereof, which may be utilized
with the present invention. International Application Serial No.
PCT/GB99/00833 (WO 99/49883), incorporated herein by reference, discloses
oxidized Thymosin β4 which may be utilized in accordance with the present
invention. Although the present invention is described primarily hereinafter with
respect to Tβ4 and Tβ4 isoforms, it is to be understood that the following
description is intended to be equally applicable to amino acid sequence LKKTET,
LKKTETQ, peptides and fragments comprising or consisting essentially of
LKKTET or LKKTETQ, conservative variants thereof, as well as oxidized Thymosin
β4.
[0020] Examples of contacting the damaged site include contacting the site
with a composition comprising adhesive/Tβ4 alone, or in combo with at least one
agent that enhances Tβ4 penetration, or delays or slows release of Tβ4 peptides
into the area to be treated. A subject may be a mammal, preferably human.
[0021] Tβ4, or its analogues, isoforms or derivatives, may be administered in
any suitable effective amount. For example, Tβ4 may be administered in dosages
within the range of about 0.1-50 micrograms of Tβ4, more preferably in amounts
within the range of about 1-25 micrograms.
[0022] A composition in accordance with the present invention can be
administered daily, every other day, etc., with a single administration or multiple

administrations per day of administration, such as applications 2, 3, 4 or more
times per day of administration.
[0023] Tβ4 isoforms have been identified and have about 70%, or about 75%,
or about 80% or more homology to the known amino acid sequence of Tβ4. Such
isoforms include, for example, Tβ4ala, Tβ9, Tβ10, Tβ11, Tβ12, Tβ13, Tβ14 and
Xβ15. Similar to Tβ4, the Tβ10 and Tβ15 isoforms, as well as the Tβ4 splice-
variants, have been shown to sequester actin. Tβ4, Tβ10 and Tp15, as well as
these other isoforms share an amino acid sequence, LKKTET, that appears to be
involved in mediating actin sequestration or binding. Although not wishing to be
bound to any particular theory, the activity of Tβ4 isoforms may be due, in part,
to the ability to regulate the polymerization of actin. β-thymosins appear to
depoh/merize F-actin by sequestering free G-actin. Tβ4's ability to modulate actin
polymerization may therefore be due to all, or in part, its ability to bind to or
sequester actin via the LKKTET sequence. Thus, as with Tβ4, other proteins
which bind or sequester actin, or modulate actin polymerization, including Tβ4
isoforms having the amino acid sequence LKKTET, are likely to be effective, alone
or in a combination with Tβ4, as set forth herein.
[0024] Thus, it is specifically contemplated that known Tβ4 isoforms, such as
TΒ4aim, Tβ9, Tβ10, Tβ11, Tβ12, Tβ13, Tβ14 and Tβ15, as well as Tβ4 isoforms and
Tβ4 splice-variants not yet identified, will be useful in the methods of the
invention. As such Tβ4 isoforms are useful in the methods of the invention,,
including the methods practiced in a subject. The invention therefore further
provides pharmaceutical compositions comprising Tβ4, as well as Tβ4 isoforms
Tβ4ala, Tβ9, Tβ10, Tβ11, Tβ12, Tβ13, Tβ14 and Tβ15, and a pharmaceutically
acceptable carrier.

[0025] In addition, other proteins having actin sequestering or binding
capability, or that can mobilize actin or modulate actin polymerization, as
demonstrated in an appropriate sequestering, binding, mobilization or
polymerization assay, or identified by the presence of an amino acid sequence
that mediates actin binding, such as LKKTET, for example, can similarly be
employed in the methods of the invention. Such proteins include gelsolin,
vitamin D binding protein (DBP), profilin, cofilin, adsevertin, propomyosin,
fincilin, depactin, Dnasel, villin, fragmin, severin, capping protein, β-actinin and
acumentin, for example. As such methods include those practiced in a subject,
the invention further provides pharmaceutical compositions comprising gelsolin,
vitamin D binding protein (DBP), profilin, cofilin, depactin, Dnasel, villin,
fragmin, severin, capping protein, β-actinin and acumentin as set forth herein.
Thus, the invention includes the use of a polypeptide comprising the amino acid
sequence LKKTET (which may be within its primary amino acid sequence) and
conservative variants thereof.
[0026] As used herein, the term "conservative variant" or grammatical
variations thereof denotes the replacement of an amino acid residue by another,
biologically similar residue. Examples of conservative variations include the
replacement of a hydrophobic residue such as isoleucine, valine, leucine or
methionine for another, the replacement of a polar residue for another, such as
the substitution of arginine for lysine, glutamic for aspartic acids, or glutamine
for asparagine, and the like.
[0027] Tβ4 has been localized to a number of tissue and cell types and thus,
agents which stimulate the production of Tβ4 can be added to or comprise a
composition to effect Tβ4 production from a tissue and/or a cell. Such agents

include members of the family of growth factors, such as insulin-like growth
factor (IGF-1), platelet derived growth factor (PDGF), epidermal growth factor
(EGF), transforming growth factor beta (TGF-β), basic fibroblast growth factor
(bFGF), thymosin al (Tα 1) and vascular endothelial growth factor (VEGF). More
preferably, the agent is transforming growth factor beta (TGF-β) or other
members of the TGF-β superfamily.
[0028] Additionally, agents that assist or stimulate healing may be added to a
composition along with Tβ4 or a Tβ4 isoform. Such agents include angiogenic
agents, growth factors, agents that direct differentiation of cells. For example,
and not by way of limitation, Tβ4 or a Tβ4 isoform alone or in combination can be
added in combination with any one or more of the following agents: VEGF, KGF,
FGF, PDGF, TGFβ, IGF-1, IGF-2, IL-1, prothymosin α and thymosin α11 in an
effective amount.
[0029] The actual dosage, formulation or composition that heals or prevents
inflammation, damage and degeneration may depend on many factors, including
the size and health of a subject. However, persons of ordinary skill in the art can
use teachings describing the methods and techniques for determining clinical
dosages as disclosed in PCT/US99/17282, supra, and the references cited
therein, to determine the appropriate dosage to use.
[0030] In preferred embodiments, the concentration of the polypeptide is within
a range of about 0.01-1 mole of the polypeptide per mole of the adhesive, more
preferably within a range of about 0.1-0.5 mole of the polypeptide per mole of the
adhesive, most preferably within a range of about 0.2-0.4 mole of the polypeptide
per mole of the adhesive.

[0031] Suitable formulations may include Tβ4 or a Tβ4 isoform at a
concentration within the range of about 0.001 - 10% by weight, within the range
of about 0.01 - 0.1% by weight, or even about 0.05% by weight.
[0032] The invention includes use of antibodies which interact with Tβ4
peptide or functional fragments thereof. Antibodies which consists essentially of
pooled monoclonal antibodies with different epitopic specificities, as well as
distinct monoclonal antibody preparations are provided. Monoclonal antibodies
are made from antigen containing fragments of the protein by methods well
known to those skilled in the art as disclosed in PCT/US99/17.282, supra. The
term antibody as used in this invention is meant to include monoclonal and
polyclonal antibodies.
[0033] In yet another embodiment, the invention provides a method of treating
a subject by administering an effective amount of an agent which modulates Tβ4
gene expression. The term "modulate" refers to inhibition or suppression of Tβ4
expression when Tβ4 is over expressed, and induction of expression when Tβ4 is
under expressed. The term "effective amount" means that amount of Tβ4 agent
which is effective in modulating Tβ4 gene expression resulting in effective
treatment. An agent which modulates Tβ4 or Tβ4 isoform gene expression may
be a polynucleotide for example. The polynucleotide may be an antisense, a
triplex agent, or a ribozyme. For example, an antisense directed to the structural
gene region or to the promoter region of Tβ4 may be utilized.
[0034] In another embodiment, the invention provides a method for utilizing
compounds that modulate Tβ4 activity. Compounds that affect Tβ4 activity (e.g.,
antagonists and agonists) include peptides, peptidomimetics, polypeptides,
chemical compounds, minerals such as zincs, and biological agents.


[0035] While not be bound to any particular theory, the present invention may
promote healing or prevention of inflammation or damage by inducing terminal
deoxynucleotidyl transferase (a non-template directed DNA polymerase), to
decrease the levels of one or more inflammatory cytokines, or chemokines, and to
act as a chemotactic factor for endothelial cells, and thereby promoting healing or
preventing degenerative changes in tissue brought about by injury or other
degenerative or environmental factors.
[0036] The invention is further illustrated by the following example, which is
not to be construed as limiting.
Example
Proteins and Reagents
[0037] Human fibrinogen depleted of plasminogen, fibronectin and von
Willebrand factor was purchased from Enzyme Research Laboratories (South
Bend, IN). The recombinant αC-fragment corresponding to the human fibrinogen
αC-domain (residues Aα221-610) and its truncated variants corresponding to the
NH2 and COOH-terminal halves (residues Aα221-391 and Aα392-610,
respectively) were produced in E. coli using the pET20b expression vector. The
recombinant γ-module comprising residues 148-411 of the human fibrinogen γ
chain was produced in E.coli using the same expression vector.
[0038] Bovine thrombin (1,000 NIHu/mg, aprotinin (4.4 TIU/mg), antirabbit
IgG-horseradish conjugate and fluorescein isothiocyanate (FITC) were purchased
from Sigma. Recombinant factor XIII was provided as a gift by Zymogenetics,
Inc. (Seattle, WA). Synthetic thymosin β4 was provided as a gift by Regenerx

Biopharmaceuticals, Inc. (Bethesda, MD). Anti-thymosin β4 serum was prepared
according to published methods.
Activation of factor XIII.
[0039] Factor XII in 25 mM Tris buffer, pH 8.0, with . 15 M NaCl (TBS), was
activated either with thrombin or with CaCl2, the latter was made to avoid the
presence of thrombin which could potentially activate fibrinogen. Thrombin-
activated FFXIII [FXIIIa(THr)] was made by addition of bovine thrombin to final
concentrations of 25 NIH u/ml and 2.5 CaCl2 mM. Ca2+-activated thrombin
[FXIIIa(Ca)] was made by addition of CaCl2 to final concentration of 50 mM. Final
concentration of FXIII in both mixtures was 1.5 mg/ml; both mixture were
incubated at room temperature for 10 min prior experiments.
Labeling of thymosin β4 with FITC
[0040] Fluorescence labeled thymosin β4 was prepared by the reaction with
fluorescein isothiocyanate (FITC). Thymosin β4 was transferred in 0.1 M NaHCO3
buffer, pH 9.5, by gel-filtration on NAP5 Sephadex G-25 column (Amersham
Biosciences) followed by addition of a 1.2 molar excess of FITC and incubation of
the mixture at 37ºC for 2 h in the dark. Non-reacted FITC was removed on NAP5
column. The degree of labeling determined spectrophotometrically as described
was found to be 0.9 mole of FITC per mole of thymosin β4.
Solid-phase Binding Assay
[0041] The interaction between thymosin β4 and fibrin(ogen) and its fragments
in the presence or absence of FXIIIa was studies by ELISA using plastic microliter
plates. Wells of microliter plates were coated overnight at -4°C with fibrinogen


and fibrin at 10 μg/mL or with the recombinant fragments of 20 μg/ml, all in 0.1
M NaHCO3 buffer, pH 8.3. Fibrin was made by addition to the wells of a mixture
containing 10 μg/mL fibrinogen 1 NIH u/ml thrombin and 400 u/ml aprotinin,
followed by overnight incubation at +4°C. The wells were then blocked by
incubation with Super Blocker (Pierce) at 37ºC for 1 h. Following washing with
TBS containing 0.05% Tween-20 (TBS-Tween), the indicated concentrations of
thymosin β4, FXIII, FXIIIa(Thr) and FXIIIa(Ca) were added to the wells and
incubated for 2-2.5 h at 37°C. Bound (incorporated) thymosin β4 was detected
by the reaction with rabbit anti-thymosin β4 serum and peroxidase-conjugated
anti-rabbit IgG. A TMB Microwell Peroxidase Substrase was added to the wells,
and the incorporated thymosin β4was measured spectrophotometrically at 450
nm.
Incorporation of thymosin β4 into fibrinogen and fibrin
[0042] Reactions of incorporation of FITC-labeled and unlabeled thymosin β4
into fibrinogen and fibrin were performed in Eppendorf tubes containing a
mixture of fibrinogen at 3 mg/mL (9μM) and thymosin β4 or FITC-labeled
thymosin β4 at 150 μg/L (30 μM) in 100 μLTBS with 2.5 mM CaCl2. The
reactions were initiated by addition of FXIIIa(Ca) or FXIIIa(Thr) to final
concentration of 30 μg/mL. The final concentration of thrombin in the
FXIIIa(Thr)-containing mixtures was made at 2.5 NIH u/mL, sufficient to rapidly
form fibrin clot which was observed visually. The reactions with FITC-labeled
thymosin β4 lasted for 4 hours at 37ºC in the dark and were stopped by heat
inactiviation of the enzymes in boiling water for 5 min during fibrinogen and
fibrin denatured and precipitated. The pellets were centrifuged and washed 3


times in TBS and then solubilized. The amounts of fibrinogen) and FITC-labeled
thymosin β4 in the solubilized pellet were determined spertrophotomertrically
using absorption molar coefficients E280,196 = 15.0 and ε495 = 72,000 M-1cm-1,
respectively. To prepare samples with unlabeled thymosin β4 for analysis by
SDS-PAGE and Western blot the reaction mixtures at the indicated time were
heat-inactivated as above and solubilized by addition of sample buffer
(Invitrogen) containing SDS and reducing agent.
Kinetic Analysis
[0043] To analyze kinetics of the incorporation of thymosin β4 into different
fibrinogen) fragments, they were immobilized onto the wells of microliter plates
(as described above, except that the concentration of all fragments was 20
μg/mL) and incubated with several concentrations of thymosin β4 in the
presence of 10 μg/L thrombin-activated factor XIIIa. The incubation mixtures
were inhibited every 15 min during 1 hour of incubation by the addition of
iodacetamide to final concentration 10 mM incorporated thymosin β4 at each
time point was detected with rabbit anti-thymosin β4 serum as described above.
The initial rates of the reaction of incorporation (V) at different concentrations of
thymosin β4 were determined from the slopes of the reaction time course plots
and expressed as tangent α - A450/t (min), where A450 represents absorbance at
450 nm in optical units (o.u) which is proportional to the amount of incorporated
thymosin β4. Apparent Michaelis constants, Km, were obtained from Lineweaver-
Burk plots, 1/V (min/o.u.) versus 1/[S](μM-1), where [S] is concentration of
thymosin β4.


Western Blot Analysis
[0044] Detection of thymosin β4 incorporated into fibrinogen) and its
fragments was performed as follows. The samples prepared as described above
were electrophoresed and electrotransferred to a nitrocellulose membrane
(Invitrogen) as described earlier. The membrane was blocked with a casein
blocker for 1 hour and thymosin β4 was detected by the reaction with rabbit anti-
thymosin β4 serum and peroxidase-conjugated anti-rabbit IgG. Visualization of
the peroxidase-labeled protein bands was performed by the procedure
recommended by the manufacturer using a supersignal west pico
chemiluminescent substrate.
ELISA-detected Incorporation of thymosin β4 into Fibrinogen and Fibrin
[0045] To test that factor XIIIa could mediate cross-Unking of thymosin β4 to
flbrin(ogen), and to clarify the mechanism of such cross-Unking we performed a
direct study of the interaction of thymosin β4 with fibrinogen and fibrin in the
presence and absence of recombinant factor XIII. It should be noted that the
recombinant factor comprises two a subunits (a2), in contrast to plasma factor
XIII corresponds to the platelet form of factor XIII.
[0046] In ELISA experiments, when thymosin β4 at 150 μg/mL (30 μm) was
incubated with immobilized fibrinogen, only a low signal was observed in the
absence of factor XIII as well as in the presence of non-activated factor XIII
suggesting that the interaction between them is very weak, if any. When
thymosin β4 was incubated with immobilized fibrin in the absence or presence of
non-activated factor XIIIa, which was activated by the addition of CaCl2 to avoid
conversion of fibrinogen into fibrin in the wells, the signal substantially increased


suggesting that factor XIIIa mediates binding (incorporation) of thymosin β4into
fibrinogen. A similar situation was observed with immobilized fibrin except that
the level of the incorporation was higher than that into fibrinogen. The
incorporation in both cases was dose-dependent. The incorporation onto fibrin
was further increased when factor XIII was activated with thrombin instead of
Ca3+. Such differences could be due to different specific activities of these two
factor XIIIa species. These results indicate that, activated XIII, similarly to tissue
transglutaminase, mediates incorporation of thymosin β4into both fibrinogen
and fibrin. They also suggest that there is no significant non-covalent interaction
thymosin β4 and both fibrinogen and fibrin.
Further analysis of the incorporation of thymosin β4 into fibrinogen and fibrin
[0047] To further characterize factor XIIIa-mediated incorporation of thymosin
β4 into fibrin(ogen), a mixture was analyzed of thrombin, factor XIII, thymosin β4 and fibrin at different time points by immunoblotting. The mixture and the
samples for analysis were prepared as described in Experimental Procedures.
The samples were electrotransferred to a nitrocellulose membrane and probed
with anti- thymosin β4 serum. The results of immunobilizing indicate that factor
XIIIa incorporates thymosin β4 into fibrin covalently, like tissue
transglutaminase, and that the amount of the incorporated (cross-linked)
thymosin β4 seems to reach saturation after 4 hours. This time was selected to
evaluate the degree of the incorporation. For this purpose thymosin β4 was
labeled with a FITC chromophore group which enabled its direct measurement in
fibrinogen/ thymosin β4 and fibrin/ thymosin β4 mixtures. Such modification
did not influence its incorporation into either fibrinogen or fibrin based on the


pattern of incorporation revealed by Western blot analysis. A similar mixture as
above but with FITC-labeled thymosin β4 was incubated for 4 hours after which
the degree of incorporation was estimated base don the spectrophotometrically
determined amounts of fibrin(ogen) and incorporated FITC- thymosin β4 in each
sample. The results revealed that at the selected conditions, which include
physiological concentration of fibrinogen (9 μM), factor XIIIa incorporated a
substantial amount of FITC- thymosin β4, about 0.2 and 0.4 moles per mole of
fibrinogen and fibrin, respectively.
Incorporation of thymosin β4 into individual fibrin(ogen) chains
[0048] To establish which of the three fibrin(ogen) chains are involved in cross-
linking with thymosin β4, we analyzed the time course of factor XIIIa-mediated
cross-linking of fibrinogen and fibrin in the presence and absence of thymosin β4
by SDS-PAGE and Western blot. It is well known that in fibrin factor XIIIa cross-
links rapidly the COOH-terminal portions of the γ chains to produce γ-γ dimers
followed by cross-linking of the a chains to form α-a dimers, trimers, and copolymers;
fibrinogen is cross-linked in a similar way but at a slower rate. When
analyzed by SDS-APGE in reducing conditions, the bands corresponding to the
individual polypeptide chains of fibrinogen and fibrin, Aα, Bβ, γ and α, β, γ,
respectively, were well resolved. Incubation of fibrinogen with factor XIIIa
resulted in progressive depletion of the band corresponding to the γ-γ dimers and
the Aα-Aα dimers and trimers; the appearance of some material at the start
which most probably corresponds to the Aα polymers was also observed. When
fibrinogen was incubated with factor XIIIa in the presence of thymosin β4, no
substantial difference in the intensity of the bands corresponding to the


individual chains and their cross-linked variants was found. Similar results were
obtained with fibrin except that the cross-linking of its α and γ chains occurred
more rapidly, as expected, and the amount of the material at the start was
higher. Subsequent Western blot experiments revealed that after 30 min of
incubation substantial amount of thymosin β4 was incorporated into fibrinogen
Aα chain and that after 150 min of incubation some thymosin β4 was also
incorporated into the Aα-Aα dimer. The incorporation of thymosin β4 into fibrin
α chain and the α-α dimer was much more rapid and after 150 min of incubation
material of thymosin β4 was also observed in higher molecular mass forms of the
a chain (α polymers). These results indicate that the fibrinogen Aα and fibrin α
chains contain the major sites for covalent incorporation of thymosin β4. At the
same time the appearance after 150 min of incubation of a low intensity band
with the mobility between that of the γ-γ and α-α dimers suggests that thymosin
β4 could also be incorporated into the fibrin γ chains (γ-γ dimer). Alternatively,
this band may correspond to a proteolytically truncated variant of the α-α dimer.
Incorporation of thymosin β4 into recombinant fibrin(ogen) fragments
[0049] It is well established that the COOH-terminal proteins of the fibrinogen
Aα and γ chains forming the αC domain and γ-module contain reactive Gin and
Lys residues which are cross-linked by factor XIIIa in fibrin and therefore could
potentially be involved in cross-linking with thymosin β4. To test this and to
further localize the cross-linking sites for thymosin β4 in fibrin(ogen), was
analyzed incorporation of thymosin β4 into the recombinant γ-module (residues
γl48-411) and the aC-domain (Aa221-391 and Aa392-610 sub-fragments, by
SDS-PAGE and Western blotting. Incubation of the aC-domain and the γ-module


with factor XIIIa in the presence of thymosin β4 resulted in effective cross-linking
and appearance of their appearance of their higher molecular mass forms,
dimers, trimers and oligomers. At the same time, the cross-linking of the Aα221-
391 and Aα392-610 sub-fragments, which contain mainly acceptor Gln and
donor Lys residues, respectively, was much less effective. When the samples
were electrotransferred to nitrocellulose membrane and probed with anti-
thymosin β4 serum, substantial amounts of thymosin β4 were detected in the
αC-domain, the γ-module and their higher molecular mass variants, dimers,
trimers and oligomers. The incorporation into the Aα392-610 sub-fragment
monomer and oligomers was also substantial while only very small amount of
thymosin β4 was detected in the Aα221-391 oligomers. These results suggest
that thymosin β4 could be cross-linked to both the αC-domain and the γ-module,
and that the reactive Lys residues of the Aα392-610 region of the former are
involved in the cross-linking.
[0050] The above observations were confirmed by ELISA. When thymosin β4
was incubated with the immobilized γ-module or the αC-domain variants in the
presence of factor XIIIa, it was incorporated effectively into the γ-module and into
the αC-domain ad the Aα392-610 sub-fragment while the incorporation into
αC221-391 was very low. It should be noted that the incorporation of the γ-
module was almost twice lower than that of the αC-domain variants at all
concentration studied. When thymosin β4 was incubated with the same
immobilized species in the presence of non-activated factor XIII or without it, the
incorporation was very low in all cases. This suggests that, as in the case with

fibrinogen and fibrin, there is no significant non-covalent interaction between
thymosin β4 and the recombinant fragments.
[0051] It was previously shown that factor XIIIa cross-linking of the γ chains of
fibrin exhibits apparent Michaelis behavior. Assuming that factor XIIIa behaves
as a Michawlis enzyme when cross-linking thymosin β4 to the immobilized y-
module and αC-domain variants one could determine the kinetic parameters of
such cross-linking. The analysis of the kinetic data revealed the following values
of apparent Michaelis constants (Km) for the reaction of incorporation, 183 + 29
μM for the incorporation of thymosin β4 into the γ-module, and 17.6 + 2.5 μM
and 8.6 ± 3.7 μM for that into the αC-domain and its Aα392-610 sub-fragment,
respectively. The much higher Km, value for the γ-module than those for the αC-
domain and its sub-fragment indicates that the cross-linking of thymosin β4 to
the αC-domain variants is much more efficient. In this connection, the Km for the
Aα392-610 fragment is comparable to the Km = 6.2 μM determined previously for
the factor XIIIa-mediated γ-γ cross-linking. The two-fold difference in the Km
values for the αC-domain and the Aα392-610 sub-fragment could be explained by
competition between reactive Gin residues of thymosin β4 and the αC392-610
region, i.e., between αC-to-αC and thymosin β4-to-αC cross-linking. In
agreement, the double-reciprocal, plot for the αC-domain and the Aα3962-610
sub-fragment exhibits a pattern characteristic for competitive inhibition.
[0052] Altogether, the results indicted that factor XIIIa effectively cross-links
thymosin β4 to the COOH-terminal portion of the isolated αC-domain including
residues αC3962-610, that the incorporation into the isolated γ-module is less

effective, and that in fibrinogen or fibrin the incorporation occurs mainly in the
αC-domains.
[0053] Fibrin(ogen) plays an important role in wound healing through
interactions with physiologically active proteins and cell receptors. Particularly,
the fibrin matrix stimulates an inflammatory response and capillary tube
formation by endothelial cells (angiogenesis), which are essential steps in the
wound healing process, through interaction with the leukocyte integrin Mac-1
and endothelial cell receptor VE-cadherin, respectively; It also interacts with
high affinity with basic fibroblast growth factor (bFGF) and vascular endothelial
growth factor (VEGF) providing co-localization of these potent stimulators of
angiogenesis at sites of fibrin deposition and their contribution to wound healing.
Fibrin can also retain at insulin-like growth factor binding protein-3 (IGFPB-3),
which forms a complex with IGF-1. Thymosin β4, a potent angiogenic and wound
healing factor, can also be incorporated into fibrin by tissue transglutaminase
and apparently further increase the wound healing potential of fibrin matrix.
[0054] Although all transglutaminases catalyze the same reaction, formation of
covalent γ-glutamyl-€-lysyl isopeptide bonds between reactive Gin and Lys
residues, their specificity towards substrates may differ. For example, while
factor XIIIa, a plasma transglutaminase, specifically cross-links in fibrin the γ
and α chains resulting in the γ-γ dimers and α-polymers, respectively, tissue
transglutaminase is less specific and can also generate α-γ chains cross-links.
The cross-linking patterns for the serine protease inhibitor (serpin), PAI-2, to
fibrin(ogen) were also found to be different for tissue transglutaminase and factor
XIIIa. It was originally shown that thymosin β4 is incorporated into fibrin by
guinea pig liver tissue transglutaminase; its incorporation into fibrin by factor


XIIIa was hypothesized based on the facts that thrombin-activated platelets co-
release factor XIII and thymosin β4 and that the latter becomes cross-linked to
fibrin. In this study it was demonstrated directly that thymosin β4 is
incorporated by factor XIIIa to both fibrinogen and fibrin. Furthermore, it was
found that the degree of the incorporation is rather high, 0.2 and 0.4 mole of
thymosin β4 per mole of fibrinogen and fibrin, respectively. Since concentration
of fibrinogen in plasma is about 9 μM, local concentration of fibrin at places of
fibrin deposition should be much higher. Taking into account that thymosin β4
exhibits its proangiogenic activity at 0.1 nM-1 μM, such degree of incorporation is
obviously physiologically significant and should be sufficient to increase the
wound healing potential of fibrin clot.
[0055] It is known that factor XIIIa incorporates into fibrin a number of plasma
proteins, α2-antiplasmin, PAI-2, fibronectin, thrombospondin, and von Willebrand
factor. The mechanism of incorporation is established only for some of them.'
For example, fibronectin binds to the fibrin αC-domains non-covalently with high
affinity prior to covalent cross-linking with factor XIIIa; the recognition sites and
the reactive Gln and Lys residues in each protein are located in different regions
providing proper orientation of the cross-linking sites. In addition, factor XIIIa
interacts with the αC-domains further increasing the specificity of the reaction.
To test whether non-covalent binding of thymosin β4 precedes its cross-linking to
fibrin, its interaction was studied with immobilized fibrinogen and fibrin in the
presence and absence of non-activated factor XIII. In contrast to other
proangiogenic factors such as bFGF and VEGF, which exhibit high affinity to
fibrin, no noticeable non-covalent interaction was observed with thymosin β4 in
all cases. The incorporation was observed only in the presence of activated factor


XIIIa suggesting that the covalent cross-linking may be the only mechanism to
retain thymosin β4 in fibrin clot.
[0056] The results clearly indicate that although thymosin β4 could be
incorporated by factor XIIIa into the isolated γ-module and the αC-domain
variants, in fibrin(ogen) it is cross-linked mainly to the αC-domains, namely to
their Aα392-610 regions. The analysis of distribution of the identified reactive
Lys and Gln residues in thymosin β4 and fibrin(ogen) provides a reasonable
explanation for this finding. Thymosin β4 contains a reactive amine donor,
Lys38, and two amine receptors, Gln23 and Gln36, which could be involved in
the cross-linking reaction with other proteins. There are only two reactive
residues in the γ chain involved in the intermolecular γ-γ cross-linking, Gln398
(or G In399) and Lys406, both located in the γ-module. When the isolated y-
module was treated with factor XIIIa, the cross-linking seemed to occur randomly
resulting in dimers, trimers/oligorners; thymosin β4 was incorporated in all these
species. In fibrin, these regions are aligned by the DD:E interactions in an
antiparallel manner facilitating cross-linking between Gln398/399 of one chain
and Lys406 of another to form γ-γ dimers. The efficiency of this cross-linking
reaction is much higher than that between these residues and thymosin β4, and
therefore it is not surprising that little or no incorporation of thymosin β4 into the
fibrin γ chains was observed in this study.
[0057] In contrast to the γ chain, the Aα chain contains multiple reactive
glutamine and lysine residues. The following residues were found to be involved
in the cross-linking between the α chains in fibrin or the recombinant αC-
domains, Gln221, 237, 328 and 366, and Lys508, 539, 556, 580 and 601. The
Aα chain Lys303 was shown to serve as amine donor in factor XIIIa-mediated


cross-linking of the serpin α2-antiplasmia to fibrin(ogen). This Lys is not reactive
towards another serpin, PAI-2, which is cross-linked by tissue transglutaminase
and factor XIIIa through other Aα chain lysine residues, 148, 176, 183, 230, 413
and 457. The study with a synthetic peptide mimicking the cross-linking region
of α2-antiplasmm revealed that it is incorporated into fibrin a chain through 12
reactive lysine residues, Lys418, 448, 508, 539, 556 and 580, which accounted
for 78% of the total activity, and less reactive Lys208, Lys219 and/or 224,
Lys427, 429, 601 and 606. At least 10 lysine residues within fibrin(ogen) Aα368-
610 region were implicated in cross-linking reactions with fibronectin. The above
analysis indicates that most of the identified reactive residues in fibrin are
located in its αC-domains, that the 392-610 region of the αC-domain, to which
thymosin β4 is a preferentially cross-linked, contains at least 11 reactive Lys
residues, and that among these residues only half is utilized in the α-α cross-
linking. It also suggests that although thymosin β4 could compete for reactive
lysine residues involved in the α-α cross-linking, its cross-linking to the αC-
domains may occur independently of their intermolecular α-α cross-linking
providing its efficient incorporation into fibrin. Thus the reactive lysine residues
of the αC-domains not only serve for the a-across-linkmg but also simultaneously
accommodate physiologically active proteins, including thymosin. β4, which could
modulate properties of fibrin matrix contributing to wound healing and other
physiological and pathological processes.
[0058] Fibrinogen polymerizes in a controllable fashion to make a clot which
easily adheres to different cells and is non-immunogenic and biodegradable.
These make it an ideal hemostatic and bioadhesive (fibrin sealant) that has been
used increasingly in numerous surgical applications as an hemostatic agent for


the arrest of bleeding, and to assist tissue sealing and wound healing. The use of
fibrin sealants in wound healing and other therapies can be enhanced by
including bioactive agents. For example, it was shown in cellular and animal
models that fibrin can serve as a vehicle for localized delivery of antibiotics and
growth factors. While antibiotics encapsulated by fibrin are released slowly due
to low solubility, the retention of growth factors in fibrin sealants was achieved
through their high affinity interaction with fibrin, or through their direct covalent
cross-linking to it. The ability of thymosin β4 to be incorporated into fibrin(ogen)
by cross-linking with factor XIIIa could be used for its immobilization on fibrin
sealants. This study demonstrates high efficiency of such incorporation into
both fibrinogen and fibrin, supporting this approach.
[0059] In summary, experimental studies confirm that thymosin β4, a bioactive
peptide, could be Incorporated into fibrin by covalently cross-linking with factor
XIIIa, demonstrated high efficiency of its incorporation into both fibrinogen and
fibrin at physiological concentrations of the components, and localized the
incorporation sites within the Aα392-610 region of the fibrin(ogen) αC-domains.
Experimental data supports incorporation of physiologically significant amounts
of thymosin β4 into fibrin sealants for delivery to places of wound healing.
[0060] Tissue transglutaminase and presumably plasma transglutaminase,
factor XIIIa, can covalently incorporate into fibrin(ogen) a physiologically active
peptide, thymosin β4. To clarify the mechanism of this incorporation interaction
was studied of thymosin β4 with fibrinogen, fibrin, and their recombinant
fragments, the γ-module (γ chain residues 148-411), and the αC-domain (Aα
chain residues 221-610) and its truncated variants by immunoblot and ELISA.
No significant non-covalent interaction between them was detected in the


absence of activated factor XIII while in its presence thymosin β4 was effectively
incorporated into fibrin and to a lesser extent into fibrinogen. The incorporation
at physiological concentrations of fibrin(ogen) and factor XIII was significant with
molar incorporation ratios of thymosin β4 to fibrinogen and fibrin of 0.2 and 0.4, respectively. Further experiments revealed that although activated factor XIII
incorporates thymosin β4 into the isolated γ-module and αC-domain, in fibrin the
latter serves as the major incorporation site. This site was further localized to
the COOH-terminal portion of the αC-domain including residues 392-610.

WE CLAIM;
1. A composition comprising an adhesive and a polypeptide comprising amino acid
sequence LKKTET or a conservation variant thereof such as herein described wherein
said adhesive and said polypeptide are covalently bound together.
2. The composition as claimed in claim 1 wherein said adhesive is capable of adhering to
tissue of living subject.
3. The composition as claimed in claim 2 wherein said adhesive is biodegradable.
4. The composition as claimed in claim 1 wherein said adhesive is fibrin, fibrinogen,
fibrin glue, collagen, a fragment thereof, or a mixture thereof.
5. The composition as claimed in claim 1 wherein said adhesive and said polypeptide are
covalently bound by factor XIIIa.
6. The composition as claimed in claim 5 wherein said adhesive is a fragment of fibrin or
fibrionogen.
7. The composition as claimed in claim 1 wherein said polypeptide comprises amino acid
sequence KLKKTET or LKKTETQ, Thymosin β4 (Tβ4), an N-terminal variant of Tβ4,
an isoform of Tβ4, a splice-variant of Tβ4, oxidized Tβ4, oxidized Tβ4, Tβ4 sulfoxide,
lymphoid Tβ4 orpegylated Tβ4.
8. The composition as claimed in claim 1 wherein said polypeptide is recombinant or
synthetic.
9. The composition as claimed in claim 1 wherein said polypeptide is an antibody.
10. The composition as claimed in claim 9 wherein said antibody is polyclonal or
monoclonal.
11. The composition as claimed in claim 4 wherein the concentration of said polypeptide
is within a range of 0.01-1 mole said polypeptide per mole of said adhesive.

12. The composition as claimed in claim 11 wherein said range is 0.1-0.5 mole said
polypeptide per mole of said adhesive.
13. The composition as claimed in claim 12 wherein said range is 0.2-0.4 mole said
polypeptide per mole of said adhesive.

A composition comprising an adhesive and a polypeptide comprising amino
acid sequence LKKTET or a conservation variant thereof such as herein described
wherein said adhesive and said polypeptide are covalently bound together.

Documents:

2088-KOLNP-2005-CORRESPONDENCE.pdf

2088-KOLNP-2005-FORM 27.pdf

2088-KOLNP-2005-FORM-27-1.pdf

2088-KOLNP-2005-FORM-27.pdf

2088-kolnp-2005-granted-abstract.pdf

2088-kolnp-2005-granted-assignment.pdf

2088-kolnp-2005-granted-claims.pdf

2088-kolnp-2005-granted-correspondence.pdf

2088-kolnp-2005-granted-description (complete).pdf

2088-kolnp-2005-granted-examination report.pdf

2088-kolnp-2005-granted-form 1.pdf

2088-kolnp-2005-granted-form 13.pdf

2088-kolnp-2005-granted-form 18.pdf

2088-kolnp-2005-granted-form 3.pdf

2088-kolnp-2005-granted-form 5.pdf

2088-kolnp-2005-granted-gpa.pdf

2088-kolnp-2005-granted-reply to examination report.pdf

2088-kolnp-2005-granted-specification.pdf


Patent Number 226432
Indian Patent Application Number 2088/KOLNP/2005
PG Journal Number 51/2008
Publication Date 19-Dec-2008
Grant Date 17-Dec-2008
Date of Filing 24-Oct-2005
Name of Patentee REGENERX BIOPHARMACEUTICALS, INC
Applicant Address 3, BETHESDA METRO CENTER, SUITE 630, BETHESDA, MARYLAND
Inventors:
# Inventor's Name Inventor's Address
1 GOLDSTEIN ALLAN L 800, 25TH STREET, N.W., APARTMENT 1005, WASHINGTON, DC
PCT International Classification Number A61K
PCT International Application Number PCT/US2004/009614
PCT International Filing date 2004-03-31
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 60/458,399 2003-03-31 U.S.A.