Primary microcephaly is caused by mutations in genes encoding centrosomal proteins including WDR62 and KIF2A. However, mechanisms underlying human microcephaly remain elusive. By creating mutant mice ...and human cerebral organoids, here we found that WDR62 deletion resulted in a reduction in the size of mouse brains and organoids due to the disruption of neural progenitor cells (NPCs), including outer radial glia (oRG). WDR62 ablation led to retarded cilium disassembly, long cilium, and delayed cell cycle progression leading to decreased proliferation and premature differentiation of NPCs. Mechanistically, WDR62 interacts with and promotes CEP170's localization to the basal body of primary cilium, where CEP170 recruits microtubule-depolymerizing factor KIF2A to disassemble cilium. WDR62 depletion reduced KIF2A's basal body localization, and enhanced KIF2A expression partially rescued deficits in cilium length and NPC proliferation. Thus, modeling microcephaly with cerebral organoids and mice reveals a WDR62-CEP170-KIF2A pathway promoting cilium disassembly, disruption of which contributes to microcephaly.
Nonalcoholic fatty liver disease (NAFLD) has become the most common cause of chronic liver disease worldwide. Due to the growing economic burden of NAFLD on public health, it has become an emergent ...target for clinical intervention. DUSP12 is a member of the dual specificity phosphatase (DUSP) family, which plays important roles in brown adipocyte differentiation, microbial infection, and cardiac hypertrophy. However, the role of DUSP12 in NAFLD has yet to be clarified. Here, we reveal that DUSP12 protects against hepatic steatosis and inflammation in L02 cells after palmitic acid/oleic acid treatment. We demonstrate that hepatocyte specific DUSP12‐deficient mice exhibit high‐fat diet (HFD)–induced and high‐fat high‐cholesterol diet–induced hyperinsulinemia and liver steatosis and decreased insulin sensitivity. Consistently, DUSP12 overexpression in hepatocyte could reduce HFD‐induced hepatic steatosis, insulin resistance, and inflammation. At the molecular level, steatosis in the absence of DUSP12 was characterized by elevated apoptosis signal‐regulating kinase 1 (ASK1), which mediates the mitogen‐activated protein kinase (MAPK) pathway and hepatic metabolism. DUSP12 physically binds to ASK1, promotes its dephosphorylation, and inhibits its action on ASK1‐related proteins, JUN N‐terminal kinase, and p38 MAPK in order to inhibit lipogenesis under high‐fat conditions. Conclusion: DUSP12 acts as a positive regulator in hepatic steatosis and offers potential therapeutic opportunities for NAFLD.
Cocaine is known to activate microglia both in vitro and in vivo
.
High expression of microglial Toll-like receptors (TLRs) and their downstream signal transducers play critical roles in determining ...microglial activation status. Emerging reports have also demonstrated that cocaine can enhance the strength of TLR signaling. Detailed molecular mechanisms underlying this phenomenon, however, remain elusive. In this study, we investigated the role(s) of miR-124 in regulating microglial TLR4 signaling in the context of cocaine. Herein, we found a dose- and time-dependent upregulation of KLF4 in cocaine-exposed BV-2 cells and rat primary microglial cells (rPMs). KLF4 also identified as a novel 3′-UTR target directly regulated by miR-124. In parallel, miR-124 regulated multiple TLR4 signaling molecules including TLR4, MyD88, TRAF6, and IRAK1. Repeated doses of cocaine (20 mg/kg;
i.p.
) administration in mice for 7 days further validated the in vitro key findings. Also, miR-124 overexpression significantly blocked the cocaine-mediated upregulation of pro-inflammatory cytokines. In contrast, miR-124 overexpression notably increased the expression of anti-inflammatory mediators in cocaine-exposed microglial cells. Intriguingly, stereotactic administration of lentivirus-miR-124 in the striatum significantly inhibited cocaine-mediated microglial activation and locomotor hyperactivity in vivo. In summary, these findings implicate the role of miR-124 in regulating TLR4 signaling, thereby indicating a new pathway responsible for cocaine-mediated microglial activation.
The common underlying feature of most neurodegenerative diseases such as Alzheimer disease (AD), prion diseases, Parkinson disease (PD), and amyotrophic lateral sclerosis (ALS) involves accumulation ...of misfolded proteins leading to initiation of endoplasmic reticulum (ER) stress and stimulation of the unfolded protein response (UPR). Additionally, ER stress more recently has been implicated in the pathogenesis of HIV-associated neurocognitive disorders (HAND). Autophagy plays an essential role in the clearance of aggregated toxic proteins and degradation of the damaged organelles. There is evidence that autophagy ameliorates ER stress by eliminating accumulated misfolded proteins. Both abnormal UPR and impaired autophagy have been implicated as a causative mechanism in the development of various neurodegenerative diseases. This review highlights recent advances in the field on the role of ER stress and autophagy in AD, prion diseases, PD, ALS and HAND with the involvement of key signaling pathways in these processes and implications for future development of therapeutic strategies.
Cocaine is known to induce inflammation, thereby contributing in part, to the pathogenesis of neurodegeneration. A recent study from our lab has revealed a link between macroautophagy/autophagy and ...microglial activation. The current study was aimed at investigating whether cocaine could also mediate activation of astrocytes and, whether this process involved induction of autophagy. Our findings demonstrated that cocaine mediated the activation of astrocytes by altering the levels of autophagy markers, such as BECN1, ATG5, MAP1LC3B-II, and SQSTM1 in both human A172 astrocytoma cells and primary human astrocytes. Furthermore, cocaine treatment resulted in increased formation of endogenous MAP1LC3B puncta in human astrocytes. Additionally, astrocytes transfected with the GFP-MAP1LC3B plasmid also demonstrated cocaine-mediated upregulation of the green fluorescent MAP1LC3B puncta. Cocaine-mediated induction of autophagy involved upstream activation of ER stress proteins such as EIF2AK3, ERN1, ATF6 since blockage of autophagy using either pharmacological or gene-silencing approaches, had no effect on cocaine-mediated induction of ER stress. Using both pharmacological and gene-silencing approaches to block either ER stress or autophagy, our findings demonstrated that cocaine-induced activation of astrocytes (measured by increased levels of GFAP) involved sequential activation of ER stress and autophagy. Cocaine-mediated-increased upregulation of GFAP correlated with increased expression of proinflammatory mediators such as TNF, IL1B, and IL6. In conclusion, these findings reveal an association between ER stress-mediated autophagy and astrogliosis in cocaine-treated astrocytes. Intervention of ER stress and/or autophagy signaling would thus be promising therapeutic targets for abrogating cocaine-mediated neuroinflammation.
SUMMARY
Elucidating the biochemical and molecular basis of premature abscission in fruit crops should help develop strategies to enhance fruit set and yield. Here, we report that LcERF2 contributes ...to differential abscission rates and responses to ethylene in Litchi chinensis (litchi). Reduced LcERF2 expression in litchi was observed to reduce fruit abscission, concurrent with enhanced pedicel growth and increased levels of hexoses, particularly galactose, as well as pectin abundance in the cell wall. Ecoptic expression of LcERF2 in Arabidopsis thaliana caused enhanced petal abscission, together with retarded plant growth and reduced pedicel galactose and pectin contents. Transcriptome analysis indicated that LcERF2 modulates the expression of genes involved in cell wall modification. Yeast one‐hybrid, dual‐luciferase reporter and electrophoretic mobility shift assays all demonstrated that a UDP‐glucose‐4‐epimerase gene (LcUGE) was the direct downstream target of LcERF2. This result was further supported by a significant reduction in the expression of the A. thaliana homolog AtUGE2‐4 in response to LcERF2 overexpression. Significantly reduced pedicel diameter and enhanced litchi fruit abscission were observed in response to LcUGE silencing. We conclude that LcERF2 mediates fruit abscission by orchestrating cell wall metabolism, and thus pedicel growth, in part by repressing the expression of LcUGE.
Significance Statement
This study shed light upon the critical role of LcERF2 in regulating organ abscission by repressing the expression of LcUGE and thus inhibiting cell wall biosynthesis and organ growth. In addition, our work revealed the role of LcUGE in pedicel development and fruit abscission in litchi, and demonstrated that LcERF2 repressed the expression of LcUGE by binding to a region 800–850 bp upstream.
Although cocaine exposure has been shown to potentiate neuroinflammation by upregulating glial activation in the brain, the role of mitophagy in this process remains an enigma. In the present study, ...we sought to examine the role of impaired mitophagy in cocaine-mediated activation of microglia and to determine the ameliorative potential of superoxide dismutase mimetics in this context. Our findings demonstrated that exposure of mouse primary microglial cells (mPMs) to cocaine resulted in decreased mitochondrial membrane potential, that was accompanied by increased expression of mitophagy markers, PINK1 and PRKN. Exposure of microglia to cocaine also resulted in increased expression of DNM1L and OPTN with a concomitant decrease in the rate of mitochondrial oxygen consumption as well as impaired mitochondrial functioning. Additionally, in the presence of cocaine, microglia also exhibited upregulated expression of autophagosome markers, BECN1, MAP1LC3B-II, and SQSTM1. Taken together, these findings suggested diminished mitophagy flux and accumulation of mitophagosomes in the presence of cocaine. These findings were further confirmed by imaging techniques such as transmission electron microscopy and confocal microscopy. Cocaine-mediated activation of microglia was further monitored by assessing the expression of the microglial marker (ITGAM) and the inflammatory cytokine (Tnf, Il1b, and Il6) mRNAs. Pharmacological, as well as gene-silencing approaches aimed at blocking both the autophagy/mitophagy and SIGMAR1 expression, underscored the role of impaired mitophagy in cocaine-mediated activation of microglia. Furthermore, superoxide dismutase mimetics such as TEMPOL and MitoTEMPO were shown to alleviate cocaine-mediated impaired mitophagy as well as microglial activation.
Abbreviations: 3-MA: 3-methyladenine; Δψm: mitochondrial membrane potential; ACTB: actin, beta; AIF1: allograft inflammatory factor 1; ATP: adenosine triphosphate; BAF: bafilomycin A
1
; BECN1: beclin 1, autophagy related; CNS: central nervous system; DNM1L: dynamin 1 like; DMEM: Dulbecco modified Eagle medium; DAPI: 4,6-Diamidino-2-phenylindole; DRD2: dopamine receptor D2; ECAR: extracellular acidification rate; FBS: fetal bovine serum; FCCP: Trifluoromethoxy carbonylcyanide phenylhydrazone; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; IL1B: interleukin 1, beta; IL6: interleukin 6; ITGAM: integrin subunit alpha M; MAP1LC3B: microtubule-associated protein 1 light chain 3 beta; mPMs: mouse primary microglial cells; MRC: maximal respiratory capacity; NFKB: nuclear factor kappa B; NLRP3: NLR family pyrin domain containing 3; NTRK2: neurotrophic receptor tyrosine kinase 2; OCR: oxygen consumption rate; OPTN: optineurin; PBS: phosphate buffered saline; PINK1: PTEN induced putative kinase 1; PRKN: parkin RBR E3 ubiquitin protein ligase; ROS: reactive oxygen species; siRNA: small interfering RNA; SQSTM1: sequestosome 1; TNF: tumor necrosis factor
•HIV (+) individuals on cART and abused drugs ages faster than HIV (-) population.•The accelerating aging process is linked with chronic inflammation.•HIV proteins, abused drugs, and cART ...individually dysregulates autophagy.•HIV proteins, abused drugs, and cART together leads to higher neuroinflammation.
In the era of combined antiretroviral therapy (cART), HIV-1 infection has transformed from adeath sentenceto a manageable, chronic disease. Although the lifeexpectancy of HIV+ individuals is comparable to that of the uninfectedsubjects paradoxically, there is increased prevalence ofage-associatedcomorbidities such asatherosclerosis, diabetes, osteoporosis & neurological deficits in the context of HIV infection. Drug abuse is a commoncomorbidityofHIV infection andis often associated withincreased neurological complications. Chronic neuroinflammation (abnormal microglial and astrocyte activation) and neuronal synaptodendritic injury are the features of CNS pathology observed inHIV (+) individualsthat are takingcART & that abuse drugs. Neuroinflammation is thedrivingforceunderlying prematureaging associated with HIV (+) infection, cART and drugs of abuse. Autophagy is a highly conserved process critical for maintaining cellular homeostasis. Dysregulated autophagyhas been shown to be linked with abnormal immune responses & aging. Recent emerging evidence implicatesthe role ofHIV/HIV proteins, cART, & abused drugsin disrupting theautophagy process in brain cells such as microglia, astrocytes, and neurons. It can thus be envisioned that co-exposure of CNS cells to HIV proteins, cART and/or abused drugs couldhavesynergistic effects on theautophagy process, thereby leading to exaggerated microglial/astrocyte activation, ultimately, promotingthe aging process. Restoration of autophagic functioncould thusprovide an alternative therapeuticstrategy formitigating neuroinflammation & ameliorating the premature aging process. The current review aims to unravel the role of dysregulated autophagy in the context of single or co-exposure of microglia, astrocytes, and neurons to HIV/HIV proteins, drugs of abuse &/or cART and will also discuss the pathways involved in dysregulated autophagy-mediated neuroinflammation.
Light has shown an incredible capability in precision measurement based on optomechanic interaction in high vacuum by isolating environment noises. However, there are still obstructions, such as ...displacement and mass estimation error, highly hampering the improvement of absolute accuracy at the nanoscale. Here, we present a nonlinearity based metrology to precisely measure the position and mass of a nanoparticle with optical levitation under 10−5 mbar . By precisely controlling the oscillation amplitude of the levitated nanoparticle at the nonlinear regime for high accuracy calibration, we realized a feasible sub-picometer-level position measurement with an uncertainty of 1.0% without the prior information of mass, which can be further applied to weigh the femtogram-level mass with an uncertainty of 2.2%. It will also pave the way to construct a fine-calibrated optomechanic platform in high vacuum for high sensitivity and accuracy measurement in force and acceleration at the nanoscale and the study in quantum superposition at the mesoscopic scale.
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