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Objectives: Hepatic stellate cells (HSC) trans-differentiation is central to the development of liver fibrosis, marked by the expression of pro-fibrogenic genes and the proliferation and migration of activated HSC. Therefore, preventing and/or reverting the activation, proliferation, and migration of HSC may lead to new therapies for treating fibrosis/cirrhosis. Thymosin β4 (Tβ4) inhibits PDGF-BB-induced fibrogenesis, proliferation and migration of HSC by blocking Akt phosphorylation. Here, we utilized Tβ4-derived peptides: amino-terminal-Ac-SDKPDMAEIEKFDKS (1-15aa) and actin-binding-LKKTETQ (17-23aa) to investigate the molecular mechanisms in the anti-fibrogenic actions of Tβ4., Methods: We used RT-PCR, Western blot, and proliferation and migration assays in early passages of human HSC cultures treated with PDGF-BB and/or Tβ4 peptides., Results: We showed that 17-23aa but not 1-15aa inhibited PDGF-BB-dependent up-regulation of PDGFβ receptor, α-SMA, and collagen 1. It also blunted the phosphorylation of Akt at T 308 and S473, resulting in the inhibition of phosphorylation of PRAS40, and HSC proliferation and migration. Interestingly, 1-15aa blocked Akt phosphorylation at S473, but not T308 by inhibiting mTOR phosphorylation, thus, it did not have any effect on HSC proliferation and migration., Conclusion: These findings suggest that while 1-15aa has a minor effect on Akt phosphorylation, the anti-fibrogenic actions of Tβ4 are exerted via 17-23aa.

Objective: Thymosin beta 4 (Tβ4) is a peptide with 43 amino acids that is critical for repair and remodeling tissues on the skin, eye, heart, and neural system following injury. To fully realize its utility as a treatment for disease caused by injury, the authors constructed a cost-effective novel Tβ4 dimer and demonstrated that it was better able to accelerate tissue repair than native Tβ4., Methods: A prokaryotic vector harboring two complete Tβ4 genes with a short linker was constructed and expressed in Escherichia coli. A pilot-scale fermentation (10 L) was performed to produce engineered bacteria and the Tβ4 dimer was purified by one-step hydrophobic interaction chromatography. The activities of the Tβ4 dimer to promote endothelial cell proliferation, migration, and sprouting were assessed by tetramethylbenzidine (methylthiazol tetrazolium), trans-well, scratch, and tube formation assays. The ability to accelerate dermal healing was assessed on rats., Results: After fermentation, the Tβ4 dimer accounted for about 30% of all the bacteria proteins. The purity of the Tβ4 dimer reached 98% after hydrophobic interaction chromatography purification. An average of 562.4 mg/L Tβ4 dimer was acquired using a 10 L fermenter. In each assay, the dimeric Tβ4 exhibited enhanced activities compared with native Tβ4. Notably, the ability of the dimeric Tβ4 to promote cell migration was almost two times higher than that of Tβ4. The rate of dermal healing in the dimeric Tβ4-treated rats was approximately 1 day faster than with native Tβ4-treated rats., Conclusion: The dimeric Tβ4 exhibited enhanced activity on wound healing than native Tβ4, and the purification process was simple and cost-effective. This data could be of significant benefit for the high pain and morbidity associated with chronic wounds disease. A better strategy to develop Tβ4 as a treatment for other diseases caused by injuries such as heart attack, neurotrophic keratitis, and multiple sclerosis was also described.

β-thymosins, including thymosin β4 (Tβ4), Tβ10, and Tβ15, are a family of highly conserved 5 kDa peptides. They are involved not only in normal cell migration, but also in tumor metastasis. However, the molecular mechanisms of β-thymosins to regulate cell migration and other functions are not fully understood. Recently, this important area is under active investigation worldwide. Many new discoveries have been made from molecular biology and cell culture models as well as animal models and human diseases. This timely review provides the most updated information about functional roles and molecular mechanisms of β-thymosins in normal tissues and disease conditions.

The downstream consequences of inflammation in the adult mammalian heart are formation of a non-functional scar, pathological remodelling and heart failure. In zebrafish, hydrogen peroxide released from a wound is the initial instructive chemotactic cue for the infiltration of inflammatory cells, however, the identity of a subsequent resolution signal(s), to attenuate chronic inflammation, remains unknown. Here we reveal that thymosin β4-sulfoxide lies downstream of hydrogen peroxide in the wounded fish and triggers depletion of inflammatory macrophages at the injury site. This function is conserved in the mouse and observed after cardiac injury, where it promotes wound healing and reduced scarring. In human T-cell/CD14+ monocyte co-cultures, thymosin β4-sulfoxide inhibits interferon-γ, and increases monocyte dispersal and cell death, likely by stimulating superoxide production. Thus, thymosin β4-sulfoxide is a putative target for therapeutic modulation of the immune response, resolution of fibrosis and cardiac repair.

Published studies have described a number of physiological properties and cellular functions of thymosin beta4 (Tbeta4), the major G-actin-sequestering molecule in mammalian cells. Those activities include the promotion of cell migration, blood vessel formation, cell survival, stem cell differentiation, the modulation of cytokines, chemokines, and specific proteases, the upregulation of matrix molecules and gene expression, and the downregulation of a major nuclear transcription factor. Such properties have provided the scientific rationale for a number of ongoing and planned dermal, corneal, cardiac clinical trials evaluating the tissue protective, regenerative and repair potential of Tbeta4, and direction for future clinical applications in the treatment of diseases of the central nervous system, lung inflammatory disease, and sepsis. A special emphasis is placed on the development of Tbeta4 in the treatment of patients with ST elevation myocardial infarction in combination with percutaneous coronary intervention.