The caveolin-1 regulated protein follistatin protects against diabetic kidney disease.

Glomerular matrix protein accumulation, mediated largely by mesangial cells, is central to the pathogenesis of diabetic kidney disease. Our previous studies showed that the membrane microdomains caveolae and their marker protein caveolin-1 regulate matrix protein synthesis in mesangial cells in response to diabetogenic stimuli, and that caveolin-1 knockout mice are protected against diabetic kidney disease. In a screen to identify the molecular mechanism underlying this protection, we also established that secreted antifibrotic glycoprotein follistatin is significantly upregulated by caveolin-1 deletion. Follistatin potently neutralizes activins, members of the transforming growth factor-ß superfamily. A role for activins in diabetic kidney disease has not yet been established. Therefore, in vitro, we confirmed the regulation of follistatin by caveolin-1 in primary mesangial cells and showed that follistatin controls both basal and glucose-induced matrix production through activin inhibition. In vivo, we found activin A upregulation by immunohistochemistry in both mouse and human diabetic kidney disease. Importantly, administration of follistatin to type 1 diabetic Akita mice attenuated early diabetic kidney disease, characterized by albuminuria, hyperfiltration, basement membrane thickening, loss of endothelial glycocalyx and podocyte nephrin, and glomerular matrix accumulation. Thus, activin A is an important mediator of high glucose-induced profibrotic responses in mesangial cells, and follistatin may be a potential novel therapy for the prevention of diabetic kidney disease.

Sheng-ji Hua-yu formula promotes diabetic wound healing of re-epithelization via Activin/Follistatin regulation.

BACKGROUND: Sheng-ji Hua-yu(SJHY) formula is one of the most useful Traditional Chinese medicine (TCM) in the treatment of the delayed diabetic wound. However, elucidating the related molecular biological mechanism of how the SJHY Formula affects excessive inflammation in the process of re-epithelialization of diabetic wound healing is a task urgently needed to be fulfilled. The objectives of this study is to evaluate the effect of antagonisic expression of pro-/anti-inflammatory factors on transforming growth factor-ß(TGF-ß) superfamily (activin and follistatin) in the process of re-epithelialization of diabetic wound healing in vivo, and to characterize the involvement of the activin/follistatin protein expression regulation, phospho-Smad (pSmad2), and Nuclear factor kappa B p50 (NF-kB) p50 in the diabetic wound healing effects of SJHY formula. METHODS: SJHY Formula was prepared by pharmaceutical preparation room of Yueyang Hospital of Integrated Traditional Chinese and Western Medicine. Diabetic wound healing activity was evaluated by circular excision wound models. Wound healing activity was examined by macroscopic evaluation. Activin/follistatin expression regulation, protein expression of pSmad2 and NF-kB p50 in skin tissue of wounds were analyzed by Real Time PCR, Western blot, immunohistochemistry and hematoxylin and eosin (H&E) staining. RESULTS: Macroscopic evaluation analysis showed that wound healing of diabetic mice was delayed, and SJHY Formula accelerated wound healing time of diabetic mice. Real Time PCR analysis showed higher mRNA expression of activin/follistatin in diabetic delayed wound versus the wound in normal mice. Western Blot immunoassay analysis showed reduction of activin/follistatin proteins levels by SJHY Formula treatment 15 days after injury. Immunohistochemistry investigated the reduction of pSmad2 and NF-kB p50 nuclear staining in the epidermis of diabetic SJHY versus diabetic control mice on day 15 after wounding. H&E staining revealed that SJHY Formula accelerated re-epithelialization of diabetic wound healing. CONCLUSION: The present study found that diabetic delayed wound healing time is closely related to the high expression level of activin/follistatin, which leads to excessive inflammation in the process of re-epithelization. SJHY Formula accelerates re-epithelialization and healing time of diabetic wounds through decreasing the high expression of activin/follistatin.

Pharmacokinetic, partial pharmacodynamic and initial safety analysis of (-)-epicatechin in healthy volunteers.

(-)-Epicatechin ((-)-EPI), a naturally occurring flavanol, has emerged as a likely candidate for cocoa-based product reported reductions in cardiometabolic risk. The present study aimed to determine the safety, tolerability, pharmacokinetics and pharmacodynamics of purified (-)-EPI administered to healthy volunteers. In this phase I, open-label, two-part single- and multiple-dose study, subjects received either a single dose (n = 9) of 50, 100 or 200 mg or multiple doses (n = 8) of 50 mg daily (q.d.) or twice daily (b.i.d) for 5 days. Blood was collected at 0, 0.5, 1, 2, 4 and 6 h after (-)-EPI administration in the single and multiple dose groups (blood collection repeated in day 5). Samples were analyzed by HPLC-HR-ESI-MS for EPI and metabolite quantification. In the q.d. and b.i.d. groups, blood samples were analyzed for NO surrogates and follistatin levels as well as, platelet mitochondrial complexes I, V and citrate synthase activity levels. (-)-EPI was well tolerated and readily absorbed with further phase 2 metabolism. On day 5, in the q.d. and b.i.d. groups, there were significant increases in plasma nitrite of 30% and 17%, respectively. In the q.d. group on day 5 vs. day 1, platelet mitochondrial complexes I, IV and citrate synthase activities demonstrated a significant increase of ∼92, 62 and 8%, respectively. Average day 5 follistatin AUC levels were ∼2.5 fold higher vs. day 1 AUC levels in the b.i.d. group. (-)-EPI was safe to use, with no observed adverse effects, and our findings suggest that increases in NO metabolites, mitochondrial enzyme function and plasma follistatin levels may underlie some of the beneficial effects of cocoa products or (-)-EPI as reported in other studies.

Deacetylase inhibitors modulate the myostatin/follistatin axis without improving cachexia in tumor-bearing mice.

Muscle wasting, as occurring in cancer cachexia, is primarily characterized by protein hypercatabolism and increased expression of ubiquitin ligases, such as atrogin-1/MAFbx and MuRF-1. Myostatin, a member of the TGFbeta superfamily, negatively regulates skeletal muscle mass and we showed that increased myostatin signaling occurs in experimental cancer cachexia. On the other hand, enhanced expression of follistatin, an antagonist of myostatin, by inhibitors of histone deacetylases, such as valproic acid or trichostatin-A, has been shown to increase myogenesis and myofiber size in mdx mice. For this reason, in the present study we evaluated whether valproic acid or trichostatin-A can restore muscle mass in C26 tumor-bearing mice. Tumor growth induces a marked and progressive loss of body and muscle weight, associated with increased expression of myostatin and ubiquitin ligases. Treatment with valproic acid decreases muscle myostatin levels and enhances both follistatin expression and the inactivating phosphorylation of GSK-3beta, while these parameters are not affected by trichostatin-A. Neither agent, however, counteracts muscle atrophy or ubiquitin ligase hyperexpression. Therefore, modulation of the myostatin/follistatin axis in itself does not appear sufficient to correct muscle atrophy in cancer cachexia.