A Tobacco-Derived Thymosin β4 Concatemer Promotes Cell Proliferation and Wound Healing in Mice

Cloning, Expression and Effects of P. americana Thymosin on Wound Healing

The American cockroach (Periplaneta americana) is a medicinal insect. Its extract is used clinically to promote wound healing and tissue regeneration, but the effective medicinal components and mechanisms are not yet clear. It has been reported that human thymosin beta 4 (Tβ4) may accelerate skin wound healing, however, the role of P. americana thymosin (Pa-THYs) is still poorly understood. In the present study, we identify and analyze the DNA sequences of Pa-THYs by bioinformatics analysis. Then we clone, express, and purify the Pa-THYs proteins and evaluate the activity of recombinant Pa-THYs proteins by cell migration and proliferation assays in NIH/3T3 cells. To elucidate the role of Pa-THYs in wound healing, a mouse model is established, and we evaluate wound contraction, histopathological parameters, and the expressions of several key growth factors after Pa-THYs treatment. Our results showed that three THY variants were formed by skipping splicing of exons. Pa-THYs could promote fibroblast migration, but have no effect on fibroblast proliferation. In wound repair, Pa-THYs proteins could effectively promote wound healing through stimulating dermal tissue regeneration, angiogenesis, and collagen deposition. On the molecular mechanism, Pa-THYs also stimulated the expression of several key growth factors to promote wound healing. The data suggest that Pa-THYs could be a potential drug for promoting wound repair.

A dimeric thymosin beta 4 with novel bio-activity protects post-ischemic cardiac function by accelerating vascular endothelial cell proliferation

BACKGROUND

Thymosin beta 4 (Tβ4) is a 43-amino-acid peptide with protective properties in myocardium injury. Previously, we produced a recombinant human dimeric Tβ4 (DTβ4). Here, the cardioprotective effects of DTβ4 and the molecular mechanisms underlying its enhanced activity were investigated.

METHODS AND RESULTS

Echocardiography measurements showed that the cardioprotective effect of DTβ4 in myocardial infarction mice was significantly higher than that of wild-type Tβ4. Corresponding in vitro analyses demonstrated that the enhanced cardioprotection provided by DTβ4 was largely due to increased stimulation of angiogenesis. HPLC analysis, western blotting and qRT-PCR indicated that the enhanced pro-angiogenesis activity of DTβ4 was independent of the protein half-life and the known downstream pathways of wild-type Tβ4. Transcriptome deep sequencing (RNA-seq), BrdU incorporation assays, flow cytometry analysis and RNA interference demonstrated that the enhanced angiogenic activity of DTβ4 depended on MALAT1 (metastasis-associated lung adenocarcinoma transcript 1)-induced proliferation of vascular endothelial cells, which has not been reported for wild-type Tβ4. Moreover, transcription factor activation screening, luciferase promoter reporter assay and immunoprecipitation assay demonstrated that DTβ4 enhanced MALAT1 transcription by inhibiting the degradation of prospero-related homeobox 1 (PROX1).

CONCLUSION

This study demonstrates the potential applications and the novel bioactivity of the Tβ4 dimer. Moreover, to construct the dimer represents a new method for production of bioactive peptides that may have novel activities.