Downregulated PDIA3P1 lncRNA Impairs Trophoblast Phenotype by Regulating Snail and SFRP1 in PE.

Preeclampsia (PE) manifests as a pregnancy-specific complication arising from compromised placentation characterized by inadequate trophoblast invasion. A growing body of evidence underscores the pivotal involvement of pseudogenes, a subset of long noncoding RNAs, in the pathological processes of PE. This study presents a novel finding, demonstrating a significant downregulation of the pseudogene PDIA3P1 in PE placental tissues compared to normal tissues. In vitro functional assays revealed that suppressing PDIA3P1 hindered trophoblast proliferation, invasion, and migration, concurrently upregulating the expression of secreted frizzled-related protein 1 (SFRP1). Further exploration of the regulatory role of PDIA3P1 in PE, utilizing human trophoblasts, established that PDIA3P1 exerts its function by binding to HuR, thereby enhancing the stability of Snail expression in trophoblasts. Overall, our findings suggest a crucial role for PDIA3P1 in regulating trophoblast properties and contributing to the pathogenesis of PE, offering potential targets for prognosis and therapeutic intervention.

A novel regulated network mediated by downregulation HIF1A-AS2 lncRNA impairs placental angiogenesis by promoting ANGPTL4 expression in preeclampsia.

Preeclampsia (PE) is the predominant medical condition leading to maternal and fetal mortality, and the lack of effective treatment increases its risk to the public health. Among the numerous predisposing factors, the ineffectual remodeling of the uterine spiral arteries, which can induce abnormal placental angiogenesis, has been focused to solve the pathogenesis of PE. According to the preceding research results, abnormal expression of long non-coding RNAs (lncRNA)s could be associated with the pathological changes inducing PE. To be more specific, lncRNA HIF1A-AS2 was proposed for its potential to participate in the molecular mechanisms underlying PE. In vitro, in trophoblast cell lines HTR-8/SVneo and human umbilical vein endothelial cells HUVECs, HIF1A-AS2 knockdown inhibited cell proliferation, migration and tube formation. Mechanistically, transcription factor FOXP1 could regulate the expression of HIF1A-AS2. Moreover, a series of assays, including RNA pull down and mass spectrometry, RNA immunoprecipitation and chromatin immunoprecipitation assay, revealed that HIF1A-AS2 interacted with Lamin A/C (LMNA) to inhibit ANGPTL4 expression in trophoblast cells, thus further participating in the progression of PE. Taken together, these findings suggested that further analysis on HIF1A-AS2 could contribute to the development of prospective therapeutic strategy for PE.

Protein-Binding Function of RNA-Dependent Protein Kinase Promotes Proliferation through TRAF2/RIP1/NF-κB/c-Myc Pathway in Pancreatic ß cells.

Double-stranded RNA-dependent protein kinase (PKR), an intracellular pathogen recognition receptor, is involved both in insulin resistance in peripheral tissues and in downregulation of pancreatic ß-cell function in a kinase-dependent manner, indicating PKR as a core component in the progression of type 2 diabetes. PKR also acts as an adaptor protein via its protein-binding domain. Here, the PKR protein-binding function promoted ß-cell proliferation without its kinase activity, which is associated with enhanced physical interaction with tumor necrosis factor receptor-associated factor 2 (TRAF2) and TRAF6. In addition, the transcription of the nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB)-dependent survival gene c-Myc was upregulated significantly and is necessary for proliferation. Upregulation of the PKR protein-binding function induced the NF-κB pathway, as observed by dose-dependent degradation of IκBα, induced nuclear translocation of p65 and elevated NF-κB-dependent reporter gene expression. NF-κB-dependent reporter activity and ß-cell proliferation both were suppressed by TRAF2-siRNA, but not by TRAF6-siRNA. TRAF2-siRNA blocked the ubiquitination of receptor-interacting serine/threonine-protein kinase 1 (RIP1) induced by PKR protein binding. Furthermore, RIP1-siRNA inhibited ß-cell proliferation. Proinflammatory cytokines (TNFα) and glucolipitoxicity also promoted the physical interaction of PKR with TRAF2. Collectively, these data indicate a pivotal role for PKR's protein-binding function on the proliferation of pancreatic ß cells through TRAF2/RIP1/NF-κB/c-Myc pathways. Therapeutic opportunities for type 2 diabetes may arise when its kinase catalytic function, but not its protein-binding function, is downregulated.

Chronic Metformin Preconditioning Provides Neuroprotection via Suppression of NF-κB-Mediated Inflammatory Pathway in Rats with Permanent Cerebral Ischemia.

Accumulating evidence suggests that chronic metformin preconditioning offers potent neuroprotective effects against ischemic stroke. However, the underlying mechanisms remain largely unknown. In this study, we tested the hypothesis that chronic preconditioning with metformin conferred neuroprotection via suppression of nuclear factor kappa B (NF-κB)-mediated inflammatory pathway. Male Sprague-Dawley rats were treated with vehicle or metformin (50 mg/kg daily, i.p.) for 3 weeks and were subjected to permanent middle cerebral artery occlusion (pMCAO). At 24 h (acute phase) and 96 h (subacute phase) after pMCAO, infarct volume and neurological deficits were evaluated. Meanwhile, the activity of NF-κB and the levels of its downstream pro-inflammatory cytokines were detected at 24 h after pMCAO. Our results showed that chronic metformin preconditioning significantly reduced infarct volume and improved neurological deficits at 24 and 96 h after pMCAO. It also suppressed brain NF-κB activity, which was accompanied by a reduction of pro-inflammatory cytokines including tumor necrosis factor-α, interleukin (IL)-1ß, IL-6, and induced nitric oxide synthase in the peri-infarct regions at 24 h after pMCAO. Moreover, the microgliosis and astrocytosis induced by pMCAO were also ameliorated by chronic metformin preconditioning. Collectively, the present study provides the first evidence that suppression of NF-κB-mediated inflammatory pathway may represent one potential mechanism underlying the neuroprotection of chronic metformin preconditioning. In addition, our findings suggest that metformin, a first-line drug for glycemic control, has a practical clinical use for stroke prevention and treatment.

Upregulation of TREM2 ameliorates neuropathology and rescues spatial cognitive impairment in a transgenic mouse model of Alzheimer's disease.

Triggering receptor expressed on myeloid cells 2 (TREM2) gene is a recently identified susceptibility gene for Alzheimer's disease (AD), as its low-frequency variants increase the risk of this disease with an odds ratio similar to that of an APOE ɛ4 allele. To date, the expression and biologic functions of TREM2 under AD context remain largely unknown. Using APPswe/PS1dE9 mice, a transgenic model of AD, we showed that TREM2 was upregulated in microglia during disease progression. For the first time, we provided in vitro and in vivo evidence that this upregulation was attributed to the increased amyloid-ß (Aß)(1-42) levels in the brain. By knockdown and overexpression of TREM2 in cultured primary microglia, we revealed that TREM2 modulated microglial functions under AD context, as it facilitated Aß(1-42) phagocytosis and inhibited Aß(1-42)-triggered proinflammatory responses. Meanwhile, this modulation was dependent on DAP12, the adapter protein of TREM2. More importantly, overexpression of TREM2 in the brain of APPswe/PS1dE9 mice markedly ameliorated AD-related neuropathology including Aß deposition, neuroinflammation, and neuronal and synaptic losses, which was accompanied by an improvement in spatial cognitive functions. Taken together, our data suggest that the upregulation of TREM2 serves as a compensatory response to Aß(1-42) and subsequently protects against AD progression by modulation of microglia functions. These findings provide insights into the role of TREM2 in AD pathogenesis, and highlight TREM2 as a potential therapeutic target for this disease.

Early activation of nSMase2/ceramide pathway in astrocytes is involved in ischemia-associated neuronal damage via inflammation in rat hippocampi.

BACKGROUND: Ceramide accumulation is considered a contributing factor to neuronal dysfunction and damage. However, the underlying mechanisms that occur following ischemic insult are still unclear. METHODS: In the present study, we established cerebral ischemia models using four-vessel occlusion and oxygen-glucose deprivation methods. The hippocampus neural cells were subjected to immunohistochemistry and immunofluorescence staining for ceramide and neutral sphingomyelinase 2 (nSMase2) levels; immunoprecipitation and immunoblot analysis for nSMase2, receptor for activated C kinase 1 (RACK1), embryonic ectoderm development (EED), p38 mitogen-activated protein kinase (p38MAPK) and phosphorylated p38MAPK expression; SMase assay for nSMase and acid sphingomyelinase (aSMase) activity; real-time reverse transcription polymerase chain reaction for cytokine expression; and Nissl, microtubule-associated protein 2 and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling staining. RESULTS: We found considerable production of ceramide in astrocytes, but not in neurons, during early cerebral ischemia. This was accompanied by the induction of nSMase (but not aSMase) activity in the rat hippocampi. The inhibition of nSMase2 activity effectively reduced ceramide accumulation in astrocytes and alleviated neuronal damage to some extent. Meanwhile, the expression levels of proinflammatory cytokines, including tumor necrosis factor α (TNF-α), interleukin 1ß (IL-1ß) and IL-6, were found to be upregulated, which may have played an import role in neuronal damage mediated by the nSMase2/ceramide pathway. Although enhanced binding of nSMase2 with RACK1 and EED were also observed after cerebral ischemia, nSMase2 activity was not blocked by the TNF-α receptor inhibitor through RACK1/EED signaling. p38MAPK, but not protein kinase Cζ or protein phosphatase 2B, was able to induce nSMase2 activation after ischemia. p38MAPK can be induced by A2B adenosine receptor (A2BAR) activity. CONCLUSIONS: These results indicate that the inhibition of ceramide production in astrocytes by targeting A2BAR/p38MAPK/nSMase2 signaling may represent a viable approach for attenuating inflammatory responses and neuronal damage after cerebral ischemia.

Elevated toll-like receptor 3 inhibits pancreatic ß-cell proliferation through G1 phase cell cycle arrest.

Activation of the innate and acquired immune systems plays an important role in chronic inflammatory diseases and conditions such as obesity, insulin resistance, type 2 diabetes mellitus and atherosclerosis, with additional roles in regulation of cell proliferation and survival. Here, we provide evidence that TLR3 can respond to nutrient signals and induce loss of ß-cell mass through induction of G1 cycle arrest. Activation of TLR3 by polyinosinic-polycytidylic acid [poly (I:C)] was shown to trigger the decline of cyclin D1/2 protein levels in pancreatic ß-cell lines, which could be reversed by the proteasome inhibitor MG132. P38 was also found to interfere with this degradation which may be associated with G1 cycle arrest. Moreover, inhibitory effects of TLR3 on ß-cell growth were supported by gene silencing of TRIF, which could inhibit p38 activity in response to poly (I:C) stimuli. These results support a role for TLR3 in ß-cell mass loss in metabolic surplus and raise the possibility that TRIF/p38 signaling may be involved in G1 phase cycle arrest through ubiquitin/proteasome-dependent degradation of cyclin D.