thymosin-beta(4) and Fibrosis

Fibrosis is a pathological process in which parenchymal cells are necrotic and excess extracellular matrix (ECM) is accumulated due to dysregulation of tissue injury repair. Thymosin β4 (Tβ4) is a 43 amino acid multifunctional polypeptide that is involved in wound healing. Prolyl oligopeptidase (POP) is the main enzyme that hydrolyzes Tβ4 to produce its derivative N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) which is found to play a role in the regulation of fibrosis. Accumulating evidence suggests that the Tβ4-POP-Ac-SDKP axis widely exists in various tissues and organs including the liver, kidney, heart, and lung, and participates in the process of fibrogenesis. Herein, we aim to elucidate the role of Tβ4-POP-Ac-SDKP axis in hepatic fibrosis, renal fibrosis, cardiac fibrosis, and pulmonary fibrosis, as well as the underlying mechanisms. Based on this, we attempted to provide novel therapeutic strategies for the regulation of tissue damage repair and anti-fibrosis therapy. The Tβ4-POP-Ac-SDKP axis exerts protective effects against organ fibrosis. It is promising that appropriate dosing regimens that rely on this axis could serve as a new therapeutic strategy for alleviating organ fibrosis in the early and late stages.

Topics: Fibrosis; Humans; Oligopeptides; Prolyl Oligopeptidases; Thymosin

There is an urgent need for new treatments for chronic kidney disease (CKD). Thymosin-β4 is a peptide that reduces inflammation and fibrosis and has the potential to restore endothelial and epithelial cell injury, biological processes involved in the pathophysiology of CKD. Therefore, thymosin-β4 could be a novel therapeutic direction for CKD.. Here, we review the current evidence on the actions of thymosin-β4 in the kidney in health and disease. Using transgenic mice, two recent studies have demonstrated that endogenous thymosin-β4 is dispensable for healthy kidneys. In contrast, lack of endogenous thymosin-β4 exacerbates mouse models of glomerular disease and angiotensin-II-induced renal injury. Administration of exogenous thymosin-β4, or its metabolite, Ac-SDKP, has shown therapeutic benefits in a range of experimental models of kidney disease.. The studies conducted so far reveal a protective role for thymosin-β4 in the kidney and have shown promising results for the therapeutic potential of exogenous thymosin-β4 in CKD. Further studies should explore the mechanisms by which thymosin-β4 modulates kidney function in different types of CKD. Ac-SDKP treatment has beneficial effects in many experimental models of kidney disease, thus supporting its potential use as a new treatment strategy.

Topics: Animals; Disease Models, Animal; Fibrosis; Humans; Inflammation; Kidney; Mice; Mice, Transgenic; Renal Insufficiency, Chronic; Thymosin

Thymosin β4 (Tβ4) is a thymic hormone with multiple and different intracellular and extracellular activities affecting wound healing, inflammation, fibrosis and tissue regeneration. As the failure to resolve inflammation leads to uncontrolled inflammatory pathology which underlies many chronic diseases, the endogenous pathway through which Tβ4 may promote inflammation resolution becomes of great interest. In this review, we discuss data highlighting the efficacy of Tβ4 in resolving inflammation by restoring autophagy.. The authors provide an overview of the Tβ4's anti-inflammatory properties in several pathologies and provide preliminary evidence on the ability of Tβ4 to resolve inflammation via the promotion of non-canonical autophagy associated with the activation of the DAP kinase anti-inflammatory function.. Based on its multitasking activity in various animal studies, including tissue repair and prevention of chronic inflammation, Tβ4 may represent a potential, novel treatment for inflammatory diseases associated with defective autophagy.

Topics: Animals; Autophagy; Down-Regulation; Fibrosis; Humans; Inflammation; Thymosin; Wound Healing

Thymosin beta 4 (Tβ4) is a ubiquitous protein with diverse biological functions. The effecter molecules targeted by Tβ4 in cardiac protection remain unknown. We summarize previously published work showing that treatment with Tβ4 in the myocardial infarction setting improves cardiac function by activating Akt phosphorylation, promoting the ILK-Pinch-Parvin complex, and suppressing NF-κB and collagen synthesis. In the presence of Wortmannin, Tβ4 showed minimal cardiac protection. In vitro findings revealed that pretreatment with Tβ4 resulted in reduction of intracellular ROS in the cardiac fibroblasts and was associated with increased expression of antioxidant enzymes, reduction of Bax/Bcl(2) ratio, and attenuation of profibrotic genes. Silencing of Cu/Zn-SOD, catalase, and Bcl(2) genes abrogated the protective effect of Tβ4. Our findings suggest that Tβ4 improves cardiac function by enhancing Akt and ILK activation and suppressing NF-κB activity and collagen synthesis. Furthermore, Tβ4 selectively upregulates catalase, Cu/Zn-SOD, and Bcl(2), thereby protecting cardiac fibroblasts from H(2)O(2) -induced oxidative damage. Further studies are warranted to elucidate the signaling pathway(s) involved in the cardiac protection afforded by Tβ4.

Topics: Animals; Antioxidants; Fibrosis; Heart; Humans; Inflammation; NF-kappa B; Thymosin

Substantial evidence demonstrates a link of increased plasminogen activator inhibitor-1 (PAI-1) and glomerulosclerosis and kidney fibrosis, providing a novel therapeutic option for prevention and treatment of chronic kidney diseases. Several mechanisms contributing to increased PAI-1 will be addressed, including classic key profibrotic factors such as the renin-angiotensin-system (RAS) and transforming growth factor-beta (TGF-b???and novel molecules identified by proteomic analysis, such as thymosin- b4. The fibrotic sequelae caused by increased PAI-1 in kidney depend not only on its classic inhibition of tissue-type and urokinase-type plasminogen activators (tPA and uPA), but also its influence on cell migration.

Topics: Angiotensins; Animals; Chronic Disease; Disease Models, Animal; Fibrosis; Humans; Kidney Diseases; Mice; Oligopeptides; Organ Specificity; Plasminogen Activator Inhibitor 1; Renin-Angiotensin System; Thymosin; Transforming Growth Factor beta1

Wound healing involves a rapid response to the injury by circulating cells, followed by inflammation with an influx of inflammatory cells that release various factors. Soon after, cellular proliferation begins to replace the damaged cells and extracellular matrix, and then tissue remodeling restores normal tissue function. Various factors can lead to pathological wound healing when excessive and irreversible connective tissue/extracellular matrix deposition occurs, resulting in fibrosis. The process is initiated when immune cells, such as macrophages, release soluble factors that stimulate fibroblasts. TGFβ is the most well-characterized macrophage derived pro-fibrotic mediator. Other soluble mediators of fibrosis include connective tissue growth factor (CTGF), platelet-derived growth factor (PDGF), and interleukin 10 (IL-10). Thymosin β4 (Tβ4) has shown therapeutic benefit in preventing fibrosis/scarring in various animal models of fibrosis/scarring. The mechanism of action of Tβ4 appears related, in part, to a reduction in the inflammatory response, including a reduction in macrophage infiltration, decreased levels of TGFβ and IL-10, and reduced CTGF activation, resulting in both prevention of fibroblast conversion to myofibroblasts and production of normally aligned collagen fibers. The amino N-terminal end of Tβ4, SDKP (serine-aspartate-lysine-proline), appears to contain the majority of anti-fibrotic activity and has shown excellent efficacy in many animal models of fibrosis, including liver, lung, heart, and kidney fibrosis. Ac-SDKP not only prevents fibrosis but can reverse fibrosis. Unanswered questions and future directions will be presented with regard to therapeutic uses alone and in combination with already approved drugs for fibrosis.

Topics: Animals; Cicatrix; Fibrosis; Interleukin-10; Thymosin; Transforming Growth Factor beta

Hepatic sinusoidal obstruction syndrome (HSOS) is a life-threatening complication that may occur after hematopoietic stem cell transplantation (HSCT). Hepatic sinusoidal endothelial cell (HSEC) injury and liver fibrosis are key mechanisms of HSOS. Thymosin β4 (Tβ4) is an active polypeptide that functions in a variety of pathologic and physiologic states, including inflammation regulation, anti-apoptosis, and anti-fibrosis. In this study, we found that Tβ4 can stimulate HSEC proliferation, migration, and tube formation in vitro via activation of pro-survival signaling AKT (protein kinase B). In addition, Tβ4 resisted γ irradiation-induced HSEC growth arrest and apoptosis in parallel with upregulation of anti-apoptotic protein B cell lymphoma extra-large (Bcl-xL) and B cell lymphoma-2 (Bcl-2), which may be associated with activation of AKT. More importantly, Tβ4 significantly inhibited irradiation-induced pro-inflammatory cytokines in parallel with negative regulation of TLR4/MyD88/NF-κB and MAPK p38. Meanwhile, Tβ4 reduced intracellular reactive oxygen species production and upregulated antioxidants in HSECs. Additionally, Tβ4 inhibited irradiation-induced activation of hepatic stellate cells by downregulating the expression of fibrogenic markers α-SMA, PAI-1, and TGF-β. In a murine HSOS model, levels of circulating alanine aminotransferase, aspartate aminotransferase, total bilirubin, and pro-inflammatory cytokines IL-6, IL-1β, and TNF-α were significantly reduced after administration of Tβ4 peptide; furthermore, Tβ4 treatment successfully ameliorated HSEC injury, inflammatory damage, and fibrosis of the murine liver. Taken together, our findings indicate that Tβ4 stimulates proliferation and angiogenesis of HSECs, exerts a cytoprotective effect, and attenuates liver injury in a murine HSOS model, suggesting that its use may be a potential strategy to prevent and treat HSOS after HSCT.

Topics: Animals; Fibrosis; Hematopoietic Stem Cell Transplantation; Hepatic Veno-Occlusive Disease; Mice; Proto-Oncogene Proteins c-akt; Transforming Growth Factor beta

Inflammation is a critical factor in the development and progression of myocardial infarction and cardiac fibrosis. Thymosin. Real-time quantitative reverse-transcription PCR (qRT-PCR), immunohistochemistry (IHC), and Western blot were used to analyze T. T. AAV-T

Topics: Animals; Fibrosis; Hydrogen Peroxide; Inflammation; Mice; Myocardial Infarction; Myocytes, Cardiac; Thymosin

The antifibrotic peptide N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) is released from thymosin-β4 (Tβ4) by the meprin-α and prolyl oligopeptidase (POP) enzymes and is hydrolyzed by angiotensin-converting enzyme (ACE). Ac-SDKP is present in urine; however, it is not clear whether de novo tubular release occurs or if glomerular filtration is the main source. We hypothesized that Ac-SDKP is released into the lumen of the nephrons and that it exerts an antifibrotic effect. We determined the presence of Tβ4, meprin-α, and POP in the kidneys of Sprague-Dawley rats. The stop-flow technique was used to evaluate Ac-SDKP formation in different nephron segments. Finally, we decreased Ac-SDKP formation by inhibiting the POP enzyme and evaluated the long-term effect in renal fibrosis. The Tβ4 precursor and the releasing enzymes meprin-α and POP were expressed in the kidneys. POP enzyme activity was almost double that in the renal medulla compared with the renal cortex. With the use of the stop-flow technique, we detected the highest Ac-SDKP concentrations in the distal nephron. The infusion of a POP inhibitor into the kidney decreased the amount of Ac-SDKP in distal nephron segments and in the proximal nephron to a minor extent. An ACE inhibitor increased the Ac-SDKP content in all nephron segments, but the increase was highest in the distal portion. The chronic infusion of a POP inhibitor increased kidney medullary fibrosis, which was prevented by Ac-SDKP. We conclude that Ac-SDKP is released by the nephron and is part of an important antifibrotic system in the kidney.

Topics: Animals; Disease Models, Animal; Fibrosis; Kidney Diseases; Kidney Medulla; Male; Metalloendopeptidases; Nephrons; Oligopeptides; Prolyl Oligopeptidases; Rats, Sprague-Dawley; Serine Endopeptidases; Signal Transduction; Thymosin

Thymosin β4 (Tβ4) is closely associated with the cytoskeleton, inflammation, wound healing, angiogenesis, apoptosis, and myocardial regeneration, but the effects of Tβ4 treatment on chronic renal tubular interstitial fibrosis (CRTIF) are poorly known. This study aimed to examine the effects of Tβ4 on the renal apoptosis and the expression of transforming growth factor (TGF-β), E-cadherin, and α-smooth muscle actin (α-SMA) in CRTIF rat models.. Male SD rats were randomized into four groups (sham group, unilateral ureteral obstruction (UUO) group, UUO + low-dose Tβ4 group, and UUO + high-dose Tβ4 group). The pathological changes of kidney tissue and its function were assessed two weeks after UUO. In renal interstitial tissue,TGF-β, E-cadherin and α-SMA expression was detected by western blot. In tubular epithelial cells, E-cadherin and α-SMA expression was detected using Real-time qPCR and western blot. Cell apoptosis of rat renal interstitial tissue and tubular epithelial cells was evaluated by immunofluorescence and western blot.. Two weeks after UUO, no differences in blood urea nitrogen and creatinine were observed between the four groups (P > 0.05). Compared to the UUO group, Tβ4 treatment decreased the 24-h proteinuria (P < 0.001) and reduced the area of pathological change (P < 0.01); this effect was more apparent in the UUO + high-dose Tβ4 group. Compared to the UUO group, a significant decrease in TGF-β and α-SMA protein expression was observed in the high-dose Tβ4 group. The level of E-cadherin protein was lower in the UUO group than the Tβ4 groups, and high-dose Tβ4 treatment further increased E-cadherin expression and improved cell apoptosis in the renal interstitial tissue. Analysis of in vitro tubular epithelial cells showed that α-SMA mRNA and protein expression decreased, while E-cadherin mRNA and protein expression increased by Tβ4 treatment. Similarly, these changes were more significant in the UUO + high-dose Tβ4 group. Tβ4 treatment improved the apoptosis of In vitro tubular epithelial cells compared with pure TGF-β stimulation, and equally, the decrease of apoptosis was more apparent in the TGF-β + high-dose Tβ4 group.. Tβ4 treatment might alleviate the renal fibrosis and apoptosis of tubular epithelial cells through TGF-β pathway inhibition in UUO rats with CRTIF.

Topics: Actins; Animals; Apoptosis; Cadherins; Cells, Cultured; Disease Models, Animal; Epithelial Cells; Fibrosis; Kidney; Kidney Tubules; Male; Proteinuria; Rats; Rats, Sprague-Dawley; RNA, Messenger; Signal Transduction; Thymosin; Transforming Growth Factor beta; Ureteral Obstruction

Glomerular disease is characterized by morphologic changes in podocyte cells accompanied by inflammation and fibrosis. Thymosin β

Topics: Animals; Cell Movement; Cells, Cultured; Cytoskeleton; Fibrosis; Glomerulonephritis; Kidney Glomerulus; Macrophages; Male; Mice, Inbred C57BL; Mice, Knockout; Podocytes; Thymosin

Therapies that modulate inflammation and fibrosis have the potential to reduce the morbidity and mortality associated with chronic kidney disease (CKD). A promising avenue may be manipulating thymosin-β4, a naturally occurring peptide, which is the major G-actin sequestering protein in mammalian cells and a regulator of inflammation and fibrosis. Thymosin-β4 is already being tested in clinical trials for heart disease and wound healing. This editorial outlines the evidence that thymosin-β4 may also have therapeutic benefit in CKD.

Topics: Adult; Animals; Fibrosis; Humans; Inflammation; Kidney; Mice; Rats; Renal Insufficiency, Chronic; Thymosin; Wound Healing

Previously, we found thymosin β4 (Tβ4) is upregulated in glomerulosclerosis and required for angiotensin II-induced expression of plasminogen activator inhibitor-1 (PAI-1) in glomerular endothelial cells. Tβ4 has beneficial effects in dermal and corneal wound healing and heart disease, yet its effects in kidney disease are unknown. Here we studied renal fibrosis in wild-type and PAI-1 knockout mice following unilateral ureteral obstruction to explore the impact of Tβ4 and its prolyl oligopeptidase tetrapeptide degradation product, N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP), in renal fibrosis. Additionally, we explored interactions of Tβ4 with PAI-1. Treatment with Ac-SDKP significantly decreased fibrosis in both wild-type and PAI-1 knockout mice, as observed by decreased collagen and fibronectin deposition, fewer myofibroblasts and macrophages, and suppressed profibrotic factors. In contrast, Tβ4 plus a prolyl oligopeptidase inhibitor significantly increased fibrosis in wild-type mice. Tβ4 alone also promoted repair and reduced late fibrosis in wild-type mice. Importantly, both profibrotic effects of Tβ4 plus the prolyl oligopeptidase inhibitor, and late reparative effects of Tβ4 alone, were absent in PAI-1 knockout mice. Thus, Tβ4 combined with prolyl oligopeptidase inhibition is consistently profibrotic, but by itself has antifibrotic effects in late-stage fibrosis, while Ac-SDKP has consistent antifibrotic effects in both early and late stages of kidney injury. These effects of Tβ4 are dependent on PAI-1.

Topics: Animals; Collagen; Disease Models, Animal; Fibronectins; Fibrosis; Kidney; Kidney Diseases; Macrophages; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Myofibroblasts; Oligopeptides; Plasminogen Activator Inhibitor 1; Prolyl Oligopeptidases; Serine Endopeptidases; Serine Proteinase Inhibitors; Thymosin; Time Factors; Ureteral Obstruction; Urological Agents

Thymosin β4 (Tβ4), a small G-actin sequestering peptide, mediates cell proliferation, migration, and angiogenesis. Whether embryonic stem (ES) cells, overexpressing Tβ4, readily differentiate into cardiac myocytes in vitro and in vivo and enhance cardioprotection following transplantation post myocardial infarction (MI) remains unknown. Accordingly, we established stable mouse ES cell lines, RFP-ESCs and Tβ4-ESCs, expressing RFP and an RFP-Tβ4 fusion protein, respectively. In vitro, the number of spontaneously beating embryoid bodies (EBs) was significantly increased in Tβ4-ESCs at day 9, 12 and 15, compared with RFP-ESCs. Enhanced expression of cardiac transcriptional factors GATA-4, Mef2c and Txb6 in Tβ4-EBs, as confirmed with real time-PCR analysis, was accompanied by the increased number of EB areas stained positive for sarcomeric α-actin in Tβ4-EBs, compared with the RFP control, suggesting a significant increase in functional cardiac myocytes. Furthermore, we transplanted Tβ4-ESCs into the infarcted mouse heart and performed morphological and functional analysis 2 weeks after MI. There was a significant increase in newly formed cardiac myocytes associated with the Notch pathway, a decrease in apoptotic nuclei mediated by an increase in Akt and a decrease in levels of PTEN. Cardiac fibrosis was significantly reduced, and left ventricular function was significantly augmented in the Tβ4-ESC transplanted group, compared with controls. It is concluded that genetically modified Tβ4-ESCs, potentiates their ability to turn into cardiac myocytes in vitro as well as in vivo. Moreover, we also demonstrate that there was a significant decrease in both cardiac apoptosis and fibrosis, thus improving cardiac function in the infarcted heart.

Topics: Animals; Apoptosis; Cell Differentiation; Cell Line; Embryonic Stem Cells; Fibrosis; Heart; Mice; Mice, Inbred C57BL; Muscle Development; Myocardial Infarction; Myocardium; Myocytes, Cardiac; Proto-Oncogene Proteins c-akt; PTEN Phosphohydrolase; Receptors, Notch; Signal Transduction; Stem Cell Transplantation; Thymosin; Transcription Factors; Ventricular Function, Left; Ventricular Remodeling

Thymosin β(4), a low molecular weight, naturally-occurring peptide plays a vital role in the repair and regeneration of injured cells and tissues. After injury, thymosin β(4), is released by platelets, macrophages and many other cell types to protect cells and tissues from further damage and reduce apoptosis, inflammation and microbial growth. Thymosin β(4) binds to actin and promotes cell migration, including the mobilization, migration, and differentiation of stem/progenitor cells, which form new blood vessels and regenerate the tissue. Thymosin β(4) also decreases the number of myofibroblasts in wounds, resulting in decreased scar formation and fibrosis.. This article will cover the many thymosin β(4) activities that directly affect the repair and regeneration cascade with emphasis on its therapeutic uses and potential. Our approach has been to evaluate the basic biology of the molecule as well as its potential for clinical applications in the skin, eye, heart and brain.. The considerable advances in our understanding of the functional biology and mechanisms of action of thymosin β(4) have provided the scientific foundation for ongoing and projected clinical trials in the treatment of dermal wounds, corneal injuries and in the regeneration and repair of heart and CNS tissue following ischemic insults and trauma.

Topics: Animals; Apoptosis; Blood Platelets; Cell Movement; Clinical Trials as Topic; Fibrosis; Humans; Inflammation; Models, Biological; Molecular Weight; Myofibroblasts; Peptides; Phylogeny; Regeneration; Skin; Stem Cells; Thymosin; Wound Healing