Human corneal fibroblasts (HCFs) are implicated in corneal neovascularization (CRNV). The mechanisms underlying the inflammatory response in HCFs and the development of CRNV were explored in this study. Alkali burns were applied to the corneas of rats to establish a CRNV model. The expression of long noncoding RNA (lncRNA) nuclear enriched abundant transcript 1 (NEAT1) and mRNA and protein levels of nuclear factor kappa B (NF-κB)- activating protein (NKAP) were examined by quantitative real-time (qRT-PCR) and Western blot methods, respectively. Lipopolysaccharide (LPS) is used to stimulate HCFs for inflammatory response. The level of inflammation factors in HCF supernatant was detected using an enzyme-linked immunosorbent assay (ELISA). Binding and interactions between NEAT1 and miRNA 1246 (miR-1246) were determined by RNA immunoprecipitation (RIP) and RNA pull-down assays in HCFs. Compared with the control group (n = 6), NEAT1 was upregulated in the corneas of the CRNV rat model (n = 6). The expression of NEAT1 in HCFs was upregulated by LPS. Downregulation of NEAT1 suppressed the secretion of tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). NEAT1 could bind and interact with miR-1246. LPS regulated the expression of NKAP and NF-κB signaling via the NEAT1/miR-1246 pathway. Downregulation of NEAT1 in vivo inhibited CRNV progression in the CRNV rat model. The lncRNA NEAT1 induced secretion of inflammatory factors, mediated by NF-κB, by targeting miR-1246, thereby promoting CRNV progression.
Yan-hui Bai, Yong Lv, Wei-qun Wang, Guang-li Sun and Hao-hao Zhang
Jie Yang, Jianyu Shang, Suli Zhang, Hao Li and Huirong Liu
The compensatory alterations in the rennin–angiotensin–aldosterone system (RAAS) contribute to the salt–water balance and sufficient placental perfusion for the subsequent well-being of the mother and fetus during normal pregnancy and is characterized by an increase in almost all the components of RAAS. Preeclampsia, however, breaks homeostasis and leads to a disturbance of this delicate equilibrium in RAAS both for circulation and the uteroplacental unit. Despite being a major cause for maternal and neonatal morbidity and mortality, the pathogenesis of preeclampsia remains elusive, where RAAS has been long considered to be involved. Epidemiological studies have indicated that preeclampsia is a multifactorial disease with a strong familial predisposition regardless of variations in ethnic, socioeconomic, and geographic features. The heritable allelic variations, especially the genetic polymorphisms in RAAS, could be the foundation for the genetics of preeclampsia and hence are related to the development of preeclampsia. Furthermore, at a posttranscriptional level, miRNA can interact with the targeted site within the 3′-UTR of the RAAS gene and thereby might participate in the regulation of RAAS and the pathology of preeclampsia. In this review, we discuss the recent achievements of genetic polymorphisms, as well as the interactions between maternal and fetal genotypes, and miRNA posttranscriptional regulation associated with RAAS in preeclampsia. The results are controversial but utterly inspiring and attractive in terms of potential prognostic significance. Although many studies suggest positive associations with genetic mutations and increased risk for preeclampsia, more meticulously designed large-scale investigations are needed to avoid the interference from different variations.
Ping Li, Yan Hao, Feng-Hui Pan, Min Zhang, Jian-Qiang Ma and Da-Long Zhu
This study investigates the effectiveness and mechanisms of a serum- and glucocorticoid-inducible kinase 1 (SGK1) inhibitor in counteracting hyperglycemia. In an in vivo experiment, we demonstrated that after an 8-week treatment with an SGK1 inhibitor, the fasting blood glucose and HbA1c level significantly decreased in db/db mice. RT-PCR and western blot analyses revealed that intestinal SGK1 and sodium glucose co-transporter 1 (SGLT1) expression were enhanced in db/db mice. Treatment with an SGK1 inhibitor decreased excessive SGLT1 expression in the intestine of db/db mice. In vitro experiments with intestinal IEC-6 cells showed that the co-administration of an SGK1 inhibitor partly reversed the SGLT1 expression and glucose absorption that were induced by dexamethasone. In conclusion, this study revealed that the favorable effect of an SGK1 inhibitor on hyperglycemia is partly due to decreased glucose absorption through SGLT1 in the small intestine. These data collectively suggest that SGK1 may be a potent target for the treatment of diabetes and other metabolic disorders.
Huan Zhang, Xiuxia Liu, Shanshan Zhou, Ye Jia, Ying Li, Yuguo Song, Junnan Wang and Hao Wu
c-Jun N-terminal kinase (JNK) contributes to the pathogenesis of diabetic nephropathy (DN). The JNK inhibitor SP600125 was reported to ameliorate DN. However, the mechanism remained unclear. We previously reported that SP600125 activated nuclear factor erythroid 2-related factor 2 (NRF2), a governor of the cellular antioxidant defense system, in the aortas of the diabetic mice. Given the critical role of NRF2 in preventing DN, the present study aimed to test whether or not NRF2 is required for SP600125’s protection against DN. To test the role of NRF2 in SP600125’s effect, streptozotocin-induced C57BL/6 wild-type (WT) and Nrf2-knockout (KO) diabetic mice were treated in the presence or absence of SP600125, for 24 weeks. To explore the mechanism by which SP600125 activates NRF2, mouse mesangial cells (MMCs) were treated with high glucose (HG), in the presence or absence of either SP600125 or JNK siRNA. SP600125 significantly attenuated the diabetes-induced renal oxidative stress, inflammation, fibrosis, pathological change and dysfunction in the WT, but not the Nrf2 KO mice. SP600125 inactivated JNK, inhibited kelch-like ECH-associated protein 1 expression, preserved NRF2 protein and facilitated its nuclear translocation in the kidneys of the WT mice, the effects of which were similarly produced by either SP600125 or JNK siRNA in HG-treated MMCs. Further, both SP600125 and JNK siRNA alleviated HG-induced mesangial oxidative stress and expression of inflammatory and fibrotic genes. The present study demonstrates that NRF2 is required for SP600125’s protection against DN. SP600125 activates NRF2 possibly via inhibition of JNK-induced Keap1 expression.
Yabing Mi, Wangsheng Wang, Jiangwen Lu, Chuyue Zhang, Yawei Wang, Hao Ying and Kang Sun
Rupture of fetal membranes (ROM) can initiate parturition at both term and preterm. Collagen III in the compact layer of the amnion contributes to the tensile strength of fetal membranes. However, the upstream signals triggering collagen III degradation remain mostly elusive. In this study, we investigated the role of cortisol regenerated by 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1) in collagen III degradation in human amnion fibroblasts with an aim to seek novel targets for the prevention of preterm premature ROM (pPROM)-elicited preterm birth. Human amnion tissue and cultured amnion tissue explants and amnion fibroblasts were used to study the regulation of collagen III, which is composed of three identical 3α 1 chains (COL3A1), by cortisol. Cortisol decreased COL3A1 protein but not mRNA abundance in a concentration-dependent manner. Cortisone also decreased COL3A1 protein, which was blocked by 11β-HSD1 inhibition. The reduction in COL3A1 protein by cortisol was not affected by a transcription inhibitor but was further enhanced by a translation inhibitor. Autophagic pathway inhibitor chloroquine or siRNA-mediated knock-down of ATG7, an essential protein for autophagy, failed to block cortisol-induced reduction in COL3A1 protein abundance, whereas proteasome pathway inhibitors MG132 and bortezomib significantly attenuated cortisol-induced reduction in COL3A1 protein abundance. Moreover, cortisol increased COL3A1 ubiquitination and the reduction of COL3A1 protein by cortisol was blocked by PYR-41, a ubiquitin-activating enzyme inhibitor. Conclusively, cortisol regenerated in amnion fibroblasts may be associated with ROM at parturition by reducing collagen III protein abundance through a ubiquitin-proteasome pathway.
Ying Li, Fuzhe Ma, Huimin Li, Yuguo Song, Huan Zhang, Ziping Jiang and Hao Wu
Impaired wound healing is a common complication among patients with diabetes mellitus (DM), resulting in high rates of disability and mortality. Recent findings highlighted the critical role of nuclear factor erythroid 2-related factor 2 (NRF2) – a master of cellular antioxidants scavenging excessive DM-induced free radicals – in accelerating diabetic wound healing. Dimethyl fumarate (DMF) is a potent NRF2 activator used for the treatment of multiple sclerosis. However, the effect of DMF on wound healing has not been determined. The present study investigated the effect of DMF on the diabetic and the non-diabetic wound healing in streptozotocin-induced diabetic mice and non-diabetic control mice. DMF activated NRF2 signaling under both conditions. Interestingly, DMF attenuated oxidative damage and inflammation and accelerated wound closure in diabetic mice. However, this effect was not observed in non-diabetic mice. Keratinocytes were treated with normal glucose (NG), high glucose (HG) or hydrogen peroxide (H2O2), in the presence or absence of DMF to assess the role of reactive oxygen species (ROS) – inducible in DM – in mediating DMF-induced protection. Both HG and H2O2 elevated ROS, oxidative damage and inflammation, the effects of which were similarly blunted by DMF. However, in spite of the activation of NRF2, DMF lost this capability under the NG condition. The findings of this study demonstrate that ROS activate the protective effect of DMF on the diabetic wound healing.