A LincRNA-p21/miR-181 Family Feedback Loop Regulates Microglial Activation In Parkinson's Disease

BackgroundParkinson's Disease(PD)is one of the most common diseases of chronic neurodegenerative movement disorders which will undoubtedly bring a heavy burden on families and society.Existing researchs have shown that the complex interactions between environmental and genetic pathogenic factors together cause a cascade of responses to a variety of cellular molecular physiological functions,such as mitochondrial dysfunction,oxidative stress,protein regulatory system abnormalities,and so on,leading to the development of PD.In recent years,several studies have pointed out that microglia-mediated neuroinflammatory mechanisms are important starting factors for the formation of these cascades.Therefore,elucidating the molecular mechanisms of neuroinflammation in PD is key issue in PD research and has important scientific implications for the early discovery,diagnosis,and treatment of PD.Purposes:Microglia-mediated neuroinflammation plays a key role in the progression of Parkinson's disease(PD),but the mechanism of activation of microglia is not yet clear.LncRNAs and miRNAs are important regulatory factors of neurodegenerative diseases and immune-inflammatory reactions.Based on our previous studies and literature search,lincRNA-p21 could act as a downstream effector molecule of p53 and interacts with miR-181 family/PKC-8 to promote the activation of microglia.Therefore,according to the theory of competitive endogenous RNA(ceRNA),this project intends to demonstrate at molecular,cellular,and animal model levels,that lincRNA-p21 acts as a ceRNA,competitively"sponges" the miR-181 family,indirectly upregulates PKC-?,and at the same time PKC-? can also promote the expression of p53/lincRNA-p21 and form a positive feedback loop with each other to synergistically promote the activation of microglia and aggravate PD progression.The study would further enrich the existing understanding of the biological mechanisms of PD moleculars and provide a new target for the subsequent development of drug therapy for PD target genes based on the lincRNA-p21 signaling pathway.MethodsMolecular level:Through down-regulation/overexpression of p53/lincRNA-p21,PKC-?,and miR-181 families,their real-time fluorescence quantitative PCR and Western blotting techniques were used to analyze their resting and activated state in microglia.Expression and its inter-regulatory relationship;using dual luciferase reporter assays,RNA-binding protein co-immunoprecipitation(RIP),and RNA pull-down techniques,identified lincRNA-p21 as a ceRNA,competitively adsorbed and down-regulated the miR-181 family,Regulates PKC-? expression.Cellular level:After down-regulation/overexpression of p53/lincRNA-p21,PKC-?,and miR-181 family from microglia phenotypes and activation products,Western blotting and flow cytometry were used to detect microglia.Changes in cell-phenotype-associated molecules to clarify the role of p53/lincRNA-p21/miR-181 family/PKC-? loops in the activation of microglia;further study of lincRNA-p21 on microglia by flow cytometry The effects of neurotoxicity.Animal level:LPS was used to prepare the PD model of inflammation,MPTP was used to prepare the classic PD model,and the expression of p53/lincRNA-p21/miR-181 family/PKC-? loop was detected by real-time fluorescence quantitative PCR and Western blotting.Down-regulate/upregulation of lincRNA-p21 expression in the substantia nigra of mice using stereotactic injection technique,followed by real-time fluorescence quantitative PCR,Western blotting,immunofluorescence,and flow cytometry,detection of lincRNA-p21 in PD medium The activation effect of cytoplasm and neurotoxicity.ResultsLincRNA-p21 promotes microglial activation in a p53-dependent way and exacerbates its neurotoxic effects by continuously activating microglia.The miR-181 family(miR-181a/b/c/d)inhibits microglial activation by targeting PKC-?.LincRNA-p21 acts as a ceRNA and competitively "adsorbs" the miR-181 family,indirectly up-regulates PKC-?.Meanwhile,PKC-5 could also promote the expression of p53/lincRNA-p21,forming a positive feedback loop with each other to synergistically promote microglial activation.ConclusionThe p53/lincRNA-p21/miR-181 family/PKC-? forms a positive feedback loop and synergistically promotes the continuous activation of microglia and aggravates PD progression.