The endosomal sorting complex required for transport repairs the membrane to delay cell death.

The endosomal sorting complex required for transport (ESCRT) machinery plays a key role in the repair of damaged plasma membranes with puncta form and removes pores from the plasma membrane in regulated cell death, apoptosis, necroptosis, pyroptosis, ferroptosis, and autophagy. ESCRT-I overexpression and ESCRT-III-associated charged multivesicular body protein (CHMP) 4B participate in apoptosis, and the ESCRT-1 protein TSG 101 maintains low levels of ALIX and ALG-2 and prevents predisposition to apoptosis. The ESCRT-III components CHMP2A and CHMP4B are recruited to broken membrane bubble sites with the requirement of extracellular Ca2+, remove membrane vesicles from cells, and delay the time required for active MLKL to mediate necroptosis, thus preserving cell survival. CHMP4B disturbed pyroptosis by recruiting around the plasma membrane neck to remove the GSDMD pores and preserve plasma membrane integrity depending on Ca2+ influx. The accumulation of the ESCRT-III subunits CHMP5 and CHMP6 in the plasma membrane is increased by the classical ferroptosis activators erastin-1 and ras-selective lethal small molecule 3 (RSL3) upon cytosolic calcium influx and repairs the ferroptotic plasma membrane. ESCRT-III- and VPS4-induced macroautophagy, ESCRT-0-initiated microautophagy. ESCRT-I, ESCRT-II, ESCRT-III, ALIX, and VPS4A are recruited to damaged lysosomes and precede lysophagy, indicating that ESCRT is a potential target to overcome drug resistance during tumor therapy.

Urinary 6-sulfatoxymelatonin level in diabetic retinopathy patients with type 2 diabetes.

Melatonin is a powerful antioxidant. Decreased melatonin excretion has been reported to be associated with several oxidative stress-related diseases. The urinary metabolite of melatonin, 6-sulfatoxymelatonin (aMT6s), has proved to be a very reliable index of melatonin production. The present study aims to evaluate the level of urinary aMT6s in patients with type 2 diabetes mellitus and diabetic retinopathy. Urine samples were collected from 10 patients with diabetes and no diabetic retinopathy (NDR), 19 patients with nonproliferative diabetic retinopathy (NPDR), 38 patients with proliferative diabetic retinopathy (PDR), and 16 subjects without diabetes mellitus, who served as controls. The level of aMT6s in specimens was assayed by a commercial aMT6s ELISA kit, creatinine levels were also measured for each sample to get urinary aMT6s/creatinine ratio. Creatinine-adjusted urinary aMT6s values were compared among four groups. The urinary aMT6s (mean ± SD) levels were 9.95 ± 2.42, 9.90 ± 2.28, 8.40 ± 1.84 and 5.58 ± 1.33 ng/mg creatinine in the controls and in patients with NDR, NPDR, or PDR, respectively. The urinary aMT6s level of the PDR group was significantly lower than that of the control, NDR and DR groups. No significant difference was found among the control, NDR and DR groups. After adjustment for various factors (age, smoking, cancer, and coronary heart disease) that may influence the aMT6s level, the odds-ratio of urinary aMT6s comparing PDR patients to controls was 0.246 (95% confidence interval = 0.108-0.558, P = 0.001). Therefore, the urinary aMT6s level is significantly decreased in diabetic patients with PDR but not in diabetic patients without PDR, which indicates that decreased urinary aMT6s level may be associated with the pathogenesis of PDR.

Calcium mediates high glucose-induced HIF-1α and VEGF expression in cultured rat retinal Müller cells through CaMKII-CREB pathway.

AIM: To investigate the effects of high glucose (HG) medium on expression of hypoxia-inducible factor-1α (HIF-1α) and vascular endothelial growth factor (VEGF) in cultured rat retinal Müller cells and to determine the signaling pathways mediating the effects. METHODS: Primary cultures of retinal Müller cells were prepared from Sprague-Dawley rats, and incubated in a medium containg HG (30 mmol/L) in the presence of the membrane-permeable Ca(2+) chelator BAPTA-AM (10 µmol/L) or the CaMKII inhibitor KN93 (10 µmol/L). The levels of CaMKII, p-CaMKII, CREB, p-CREB, HIF-1α, and VEGF proteins were measured with Western blotting, while HIF-1á and VEGF mRNA levels were determined using real-time RT-PCR. RESULTS: The stimulation of retinal Müller cell with HG for 24 h remarkably increased the expression levels of HIF-1α and VEGF. These responses were significantly inhibited in the presence of BAPTA-AM or KN93. Both BAPTA-AM and KN93 also significantly inhibited HG-induced phosphorylation of CaMKII and CREB in the cultured retinal Müller cells. Transfection of the cultured retinal Müller cells with antisense CREB oligonucleotide (300 nmol/L) was similarly effective in blocking the HG-induced increase of HIF-1α and VEGF. CONCLUSION: HG-induced HIF-1α and VEGF expression in cultured rat retinal Müller cells depends on intracellular free Ca(2+) and activation of CaMKII-CREB pathway. The activation of CaMKII-CREB pathway by HG may be a possible mechanism underlying the pathogenesis of diabetic retinopathy.

Ginseng total saponins enhance neurogenesis after focal cerebral ischemia.

ETHNOPHARMACOLOGICAL RELEVANCE: Ginseng, the root of Panax ginseng C.A. Meyer, is one of the most commonly used healing herbs for stroke and chronic debilitating conditions in China. Ginsenosides are the main active principles for ginseng's efficacy, but the mechanisms have not been fully clarified. AIM OF THE STUDY: To test the hypothesis whether or not the administration of Ginseng total saponins (GTS) can enhance neurogenesis after focal cerebral ischemia, and thereby improve neurological deficits. MATERIALS AND METHODS: Male Wistar rats received intraperitoneal injections of GTS dissolved at a dose of 25 mg kg(-1) d(-1) or normal saline (NS) of same volume 3 days before the permanent middle cerebral artery occlusion (MCAO) model establishment until the animals were killed at the time points of 1d, 3d, 7d and 14d. The neurological function was assessed blindly. BrdU immunostaining and double staining were performed by following the 3-steps method. RESULTS: (A) GTS-treated rats have better neurological scores compared with those in NS group at 14d time point (p<0.05); (B) the number of BrdU(+) cells and BrdU(+)/NeuN(+) cells in GTS group were significantly higher than those in NS group in the ipsilateral subventricular zone and in the ipsilateral infarct area after MCAO, respectively (p<0.05 or p<0.01); (C) the increase of the number of BrdU(+)/NeuN(+) cells highly correlated with the decrease of neurological scores. Coefficient correlation r=-0.828 (p<0.01). CONCLUSION: GTS can improve neurological deficits after focal cerebral ischemia by inducing endogenous neural stem cells activation and thereby enhance adult central nervous system regeneration.

Beyond water channel: aquaporin-4 in adult neurogenesis.

Aquaporin-4 (AQP4) is a key molecule for maintaining water and ion homeostasis associated with neuronal activity in the central nervous system, but the roles of AQP4 in adult neurogenesis remain largely unexplored. Based on preliminary evidences over the past years, AQP4 appears to emerge as an important player regulating the multiple steps of adult neurogenesis. In this mini-review, we discuss the recent findings that reveal a specific functional role of AQP4 in regulating the adult neurogenesis, including proliferation of neural progenitors/neural stem cells, fate specification and differentiation, neuronal migration, and the potential mechanisms. Further studies on the regulation of AQP4 in promoting neurogenesis will lead to better understanding of the signaling mechanisms of adult neurogenesis and potentially provide an opportunity to develop AQP4 as new drug target for neurogenesis.