Taz/Tead1 Promotes Alternative Macrophage Activation and Kidney Fibrosis via Transcriptional Upregulation of Smad3.

Macrophage alternative activation is involved in kidney fibrosis. Previous researches have documented that the transcriptional regulators Yes-associated protein (Yap)/transcriptional coactivator with PDZ-binding motif (Taz) are linked to organ fibrosis. However, limited knowledge exists regarding the function and mechanisms of their downstream molecules in regulating macrophage activation and kidney fibrosis. In this paper, we observed that the Hippo pathway was suppressed in macrophages derived from fibrotic kidneys in mice. Knockout of Taz or Tead1 in macrophages inhibited the alternative activation of macrophages and reduced kidney fibrosis. Additionally, by using bone marrow-derived macrophages (BMDMs), we investigated that knockout of Taz or Tead1 in macrophages impeded both cell proliferation and migration. Moreover, deletion of Tead1 reduces p-Smad3 and Smad3 abundance in macrophages. And chromatin immunoprecipitation (ChIP) assays showed that Tead1 could directly bind to the promoter region of Smad3. Collectively, these results indicate that Tead1 knockout in macrophages could reduce TGFß1-induced phosphorylation Smad3 via transcriptional downregulation of Smad3, thus suppressing macrophage alternative activation and IRI-induced kidney fibrosis.

Resolvin D1 ameliorates cognitive impairment following traumatic brain injury via protecting astrocytic mitochondria.

Cognitive impairment is one of the most common and devastating neuropsychiatric sequelae after traumatic brain injury (TBI), and hippocampal neuronal survival plays a causal role in this pathological process. Resolvin D1 (RvD1), an important endogenous specialized pro-resolving mediator, has recently been reported to exert a potent protective effect on mitochondria. This suggests that RvD1 may suppress neuroinflammation and protect astrocytic mitochondria at the same time to play further neuroprotective roles. C57BL/6 mice subjected to TBI using a controlled cortical impact device were used for in vivo experiments. Cultured primary mouse astrocytes and an N2a mouse neuroblastoma cell line were used for in vitro experiments. In TBI mice, RvD1 significantly ameliorated cognitive impairment, suppressed gliosis and alleviated neuronal loss in the hippocampus. To explore the mechanism underlying this activity, we verified that RvD1 can induce a higher level of mitophagy to remove damaged mitochondria and eliminate extra mitochondria-derived reactive oxygen species (mitoROS) by activating ALX4/FPR2 receptors in astrocytes. In an in vitro model, we further confirmed that RvD1 can protect mitochondrial morphology and membrane potential in astrocytes and thereby enhance the survival of neurons. Meanwhile, RvD1 was also shown to increase the expression of brain-derived neurotrophic factor and glutamate aspartate transporter in the hippocampus following TBI, which indicates a possible way by which RvD1 increases the supportive function of astrocytes. These findings suggest that RvD1 may be a potent therapeutic option for ameliorating cognitive impairment following TBI by controlling neuroinflammation and protecting astrocytic mitochondria.

miR-30a attenuates cardiac fibrosis in rats with myocardial infarction by inhibiting CTGF.

The mechanism of miR-30a in myocardial fibrosis in rats with myocardial infarction (MI) was investigated. rAAV9-miR-30a was constructed and transfected to heart via injecting into the left ventricular cavity of MI rats. The sham operation group, control group, miR-30a group and miR-30a-NC group were established. Besides, the 3'-UTR of CTGF was inserted into luciferase expression plasmid (pMir-report), then transfected into COS1 cells. miR-30a and control miRNA were, respectively, cotransfected into COS1 cells. The expression of luciferase was detected before and after knockdown of the binding site of miR-30a and the 3'-UTR of CTGF. Four weeks after MI surgery, cardiac function was measured by color Doppler echocardiography, including short axis shortening (FS) and left ventricular ejection fraction (LVEF); the myocardial collagen volume fraction (CVF) was observed by Masson's staining; deposition of collagen I and collagen III were evaluated by immunohistochemical stain; using real-time PCR to detect expression levels of miR-30a and CTGF; the expression of CTGF was observed by western blotting. In MI group, cardiac function was significantly improved, while the expression levels of CVF, collagen I and III, the ratio of type I/III collagen, CTGF were significantly reduced. After knockdown the binding site of miR-30a and the 3'-UTR of CTGF, luciferase expression in COS1 cells decreased significantly. miR-30a might inhibit the expression of CTGF by directly combining with the 3'-UTR site of CTGF after MI, thereby reduce the production of collagen in myocardia, inhibit myocardial fibrosis, then improve cardiac function.