The short-chain fatty acid butyrate accelerates vascular calcification via regulation of histone deacetylases and NF-κB signaling.

Recent studies have shown that short-chain fatty acids (SCFAs), primarily acetate, propionate and butyrate, play a crucial role in the pathogenesis of cardiovascular disease. Whether SCFAs regulate vascular calcification, a common pathological change in cardiovascular tissues, remains unclear. This study aimed to investigate the potential role of SCFAs in vascular calcification. Using cellular and animal models of vascular calcification, we showed that butyrate significantly enhanced high phosphate (Pi)-induced calcification and osteogenic transition of vascular smooth muscle cells (VSMC) in vitro, whereas acetate and propionate had no effects. Subsequent studies confirmed that butyrate significantly promoted high Pi-induced aortic ring calcification ex vivo and high dose vitamin D3 (vD3)-induced mouse vascular calcification in vivo. Mechanistically, butyrate significantly inhibited histone deacetylase (HDAC) expression in VSMCs, and a pan HDAC inhibitor Trichostatin A showed similar inductive effects on calcification and osteogenic transition of VSMCs to butyrate. In addition, the SCFA sensing receptors Gpr41 and Gpr109a were primarily expressed by VSMCs, and butyrate induced the rapid activation of NF-κB, Wnt and Akt signaling in VSMCs. Intriguingly, the NF-κB inhibitor SC75741 significantly attenuated butyrate-induced calcification and the osteogenic gene Msx2 expression in VSMCs. We showed that knockdown of Gpr41 but not Gpr109a attenuated butyrate-induced VSMC calcification. This study reveals that butyrate accelerates vascular calcification via its dual effects on HDAC inhibition and NF-κB activation. Our data provide novel insights into the role of microbe-host interaction in vascular calcification, and may have implications for the development of potential therapy for vascular calcification.

Cystic fibrosis transmembrane conductance regulator ameliorates lipopolysaccharide-induced acute lung injury by inhibiting autophagy through PI3K/AKT/mTOR pathway in mice.

OBJECTIVE: The beneficial role of Cystic fibrosis transmembrane conductance regulator (CFTR) was reported in acute lung injury (ALI), however, there was no direct evidence supporting the relationship between CFTR and cell autophagy in ALI. Here, this study is to analyze the protective role of CFTR on autophagy in lipopolysaccharide (LPS)-induced ALI mice and its special mechanism. METHODS: ALI mouse models were established by the stimulation of LPS. ALI mice were subjected to tail vein injection of Lv-CFTR, intraperitoneal injection of autophagy activator RAPA or tail vein injection of Lv-sh-HMGB1 before lung tissues and bronchoalveolar lavage fluid (BALF) were collected. The expression levels of CFTR, HMGB1, Beclin-1, p62, p-AKT, p-mTOR, and LC3-II/LC3-I ratio were estimated by qRT-PCR and Western blot. The lung edema in ALI mice was inspected by wet/dry weight (W/D) ratio. Hematoxylin and eosin (H&E) staining was utilized to observe pathological features of lung tissue. Immunofluorescence was applied to determine the expression intensity of LC-3. The superoxidase dismutase (SOD) and myeloperoxidase (MPO) activity and malondialdehyde (MDA) content were assayed, and inflammatory response in ALI mice was measured. RESULTS: ALI mouse models were successfully induced by LPS, evidenced by an enhanced inflammatory response in lung tissues, heightened W/D ratio and cell autophagy markers. ALI mice had suppressed expression of CFTR, while injection of CFTR overexpression in ALI mice attenuated inflammation, autophagy, MPO activity and MDA content in addition to elevating SOD activity. Moreover, CFTR overexpression could increase the p-AKT, and p-mTOR. Overexpression of HMGB1 could reverse the expression pattern in mice injected with CFTR overexpression. CONCLUSION: CFTR could inhibit cell autophagy by enhancing PI3K/AKT/mTOR signaling pathway, thereby playing a protective role in LPS-induced ALI in mice.