Inhibition of HMGB1 ameliorates cardiac fibrosis through regulation of endothelial-to-mesenchymal transition

Natural polysaccharides as potential anti-fibrotic agents: A review of their progress

Fibrosis, as a common disease which could be found in nearly all organs, is normally initiated by organic injury and eventually ended in cellular dysfunction and organ failure. Currently, effective and safe therapeutic strategies targeting fibrogenesis still in highly demand. Natural polysaccharides derived from natural resources possess promising anti-fibrosis potential, with no deleterious side effects. Based on the etiology and pathogenesis of fibrosis, this review summarizes the intervention effects and mechanisms of natural polysaccharides in the prevention and treatment of fibrosis. Natural polysaccharides are able to regulate each phase of the fibrogenic response, including primary injury to organs, activation of effector cells, the elaboration of extracellular matrix (ECM) and dynamic deposition. In addition, polysaccharides significantly reduce fibrosis levels in multiple organs including heart, lung, liver and kidney. The investigation of the pathogenesis of fibrosis indicates that mechanisms including the inhibition of TGF-β/Smad, NF-κB, HMGB1/TLR4, cAMP/PKA signaling pathways, MMPs/TIMPs system as well as microRNAs are promising therapeutic targets. Natural polysaccharides can target these mediators or pathways to alleviate fibrosis. The information reviewed here offer new insights into the understanding the protective role of natural polysaccharides against fibrosis, help design further experimental studies related to polysaccharides and fibrotic responses, and shed light on a potential treatment for fibrosis.

Different Roles of Resident and Non-resident Macrophages in Cardiac Fibrosis

Cardiac fibrosis is a key pathological link of various cardiovascular diseases to heart failure. It is of great significance to deeply understand the development process of cardiac fibrosis and the cellular and molecular mechanisms involved. Macrophages play a special role in promoting heart development, maintaining myocardial cell homeostasis and heart function. They are involved in the whole process from inflammatory to cardiac fibrosis. This article summarizes the relationship between inflammation and fibrosis, discusses the bidirectional regulation of cardiac fibrosis by macrophages and analyses the functional heterogeneity of macrophages from different sources. It is believed that CCR2^– cardiac resident macrophages can promote cardiac function, but the recruitment and infiltration of CCR2⁺ cardiac non-resident macrophages aggravate cardiac dysfunction and heart remodeling. After heart injury, damage associated molecular patterns (DAMPs) are released in large quantities, and the inflammatory signal mediated by macrophage chemoattractant protein-1 (MCP-1) promotes the infiltration of CCR2⁺ monocytes and transforms into macrophages in the heart. These CCR2⁺ non-resident macrophages not only replace part of the CCR2^– resident macrophage subpopulation in the heart, but also cause cardiac homeostasis and hypofunction, and release a large number of mediators that promote fibroblast activation to cause cardiac fibrosis. This article reveals the cell biology mechanism of resident and non-resident macrophages in regulating cardiac fibrosis. It is believed that inhibiting the infiltration of cardiac non-resident macrophages and promoting the proliferation and activation of cardiac resident macrophages are the key to improving cardiac fibrosis and improving cardiac function.

ZC3H4 mediates silica-induced EndoMT via ER stress and autophagy

BACKGROUND

Inflammatory reactions induced by alveolar macrophages and excessive fibroblast activation lead to pulmonary fibrosis in silicosis. The endothelial-mesenchymal transition (EndoMT) is a key source of myofibroblasts. ZC3H4 is a member of the CCCH zinc finger protein family that participates in macrophage activation and epithelial mesenchymal transition (EMT). However, whether ZC3H4 is involved in EndoMT in silicosis has not yet been elucidated. Therefore, we conducted further studies into the role of ZC3H4 in silica-induced EndoMT in pulmonary vessels.

METHODS

Western blotting and immunofluorescence staining were used to detect the regulatory influences of SiO2 on pulmonary fibrosis and EndoMT. ZC3H4 was specifically downregulated using CRISPR/Cas9 to explore whether ZC3H4 regulated EndoMT during silicosis. C57BL/6 J mice were administered with SiO2 via the trachea to establish a silicosis animal model.

RESULTS

1) SiO2 exposure increased ZC3H4 expression in pulmonary vessels. 2) ZC3H4 was involved in EndoMT induced by silica. 3) ZC3H4 mediated EndoMT via endoplasmic reticulum stress (ER stress) and autophagy.

CONCLUSIONS

ZC3H4 greatly affects the progression of SiO2-induced EndoMT via ER stress and autophagy, which provides the possibility that ZC3H4 may become a novel target in pulmonary fibrosis treatment.