Quercetin, a kind of flavonoids, has been implicated in multiple neurological diseases. Nevertheless, the functional roles and mechanisms of quercetin in HIV-associated neurocognitive disorders (HAND) remain unclear. HIV-1-encoded transactivator of transcription (Tat) is the major pathogenic factor for the progression of HAND. In the central nervous system, microglia-mediated Tat neurotoxicity is mainly comprised of inflammatory response, nitric oxide (NO) and excessive glutamate. In this study, we demonstrated that Tat-activated NF-κB p65 directly induce the release of IL-6 and TNF-α as well as NO production, while Tat promoted glutamate release via NF-κB/SPI1 pathway. Conversely, quercetin could upregulate SIRT3 expression to reduce reactive oxygen species (ROS) generation, thereby inhibiting NF-κB/SPI1 pathway and mitigating microglia-mediated Tat neurotoxicity. In addition, we also observed that quercetin alleviated neuronal apoptosis induced by the microglia-derived conditioned media in a SIRT3/ROS/NF-κB-dependent manner. Furthermore, Tat was found to downregulate SIRT3 expression via NF-κB/SPI1 pathway, which was reversed by quercetin in microglia. Thus, our data establish that quercetin disrupts the SIRT3/ROS/NF-κB/SPI1 feedback loop to attenuate microglia-mediated Tat neurotoxicity. Finally, in murine models, we recapitulated that administration of quercetin remarkably ameliorated Tat‑induced neuropathy and cognitive decline in vivo. Taken together, our study uncovers the neuroprotective roles of quercetin in the amelioration of microglia-mediated Tat neurotoxicity and highlights its potential as a therapeutic agent for the treatment of HAND.

Currently, human immunodeficiency virus-1 (HIV-1) spreads around the globe and half of HIV-1-positive individuals suffer from HIV-associated neurocognitive disorder (HAND). HIV-1 infection of astrocytes leads to neuroinflammation and neuronal injury. However, the underlying molecular mechanisms of HIV-1 negative factor (Nef)-mediated astrocytic dysfunction, remain largely unclear. In the present study, our data showed that astrocytic Nef expression facilitated astrocytes proliferation, pro-inflammatory cytokines production and A1-like astrocytes polarization. Mechanistically, Nef-activated NF-κB p65 directly bound to the promoter regions of the proliferative marker (CyclinD1), the inflammatory genes (Il-6, Ccl2, Ccl5 and Cxcl10) and the A1-specific marker (C3), and upregulated these genes expression at transcriptional levels. Conversely, NF-κB signaling inhibitor BAY11-7082 (2 μM) or RNA interference targeting of NF-κB p65 markedly mitigated astrocytes-mediated Nef neurotoxicity. Moreover, Nef-transduced astrocytes-derived conditioned media induced large amount of apoptotic HT-22 and SH-SY5Y neural cells, which was remarkably reversed in response to NF-κB inhibition. Finally, in animal models, we determined that knockdown of NF-κB p65 effectively ameliorated Nef‑induced neuroinflammation, A1-like astrocytes polarization and neuronal death. Taken together, our data suggest that Nef induces astrocytes proliferation, inflammatory response, A1-like astrocytes polarization and neuronal death in a NF-κB-dependent manner. Our findings propose that NF-κB signaling might be a desirable therapeutic target for relief of astrocytes-mediated Nef neurotoxicity.

Microglial activation can cause neuroinflammation and the consequent neurological impairments play prominent roles in diabetes-associated cognitive deficits. Receptor-interacting protein kinase 1 (RIPK1) phosphorylation is involved in this deleterious microglial activation, but the exact molecular mechanisms are not clear. Here, RIPK1 expression was increased in diabetic patients with cognitive impairment. Furthermore, in diabetic mice, RIPK1 death domain directly binds to C-terminal of the receptor for advanced glycation end products (ctRAGE) could regulate RIPK1 phosphorylation in microglia. This RAGE-RIPK1 complex activates inflammatory signaling, resulting in cascades that ultimately promote cognitive impairment in diabetic mice. An engineered brain-targeting RIPK1 peptide blocked binding of RIPK1 to RAGE, which inhibited RIPK1 phosphorylation, decreased neuroinflammation, improved neuronal morphology and function, and prevented diabetes-associated cognitive deficits in mice. This study uncovers a previously unknown mechanism of neuroinflammation and suggests a novel therapeutic avenue for treating cognitive deficits induced by hyperglycemia.

Oxidized low density lipoprotein receptor 1 (OLR1), a type II integral membrane glycoprotein, is involved in multiple neurological diseases. However, the roles and mechanisms of OLR1 in HIV-associated neurocognitive disorder (HAND) remain unclear. In the central nervous system, Transactivator of transcription (Tat) induces inflammatory response in microglia, thereby leading to neuronal apoptosis. In the present study, we demonstrated that OLR1 expression was upregulated during ectopic expression of Tat or soluble Tat stimulus in BV-2 microglial cells. Moreover, OLR1 signaling was proved to facilitate Tat-triggered inflammatory response and alleviated the microglia-derived conditioned media-mediated HT-22 neural cells apoptosis in a NF-κB-dependent manner. Conversely, Tat augmented OLR1 expression via NF-κB signaling pathway. Finally, in mouse models, we determined that silencing of OLR1 significantly ameliorated Tat‑induced neuroinflammation and hippocampal neuronal death. Taken together, our study clarifies the potential role of the OLR1/NF-κB feedback loop in Tat-induced microglial inflammatory response and neuronal apoptosis, which could be a novel therapeutic target for relief of HAND.

The basal layer progenitors establish a stratified epidermis through asymmetric division and differentiation. Inactivating mutations of Receptor-interacting serine/threonine kinase 4 (RIPK4) cause human developmental syndromes characterized by defective epidermal differentiation. While the Hippo pathway is crucial in limiting organ size, emerging evidence suggests that it also plays additional roles in differentiation. In this study, we identify RIPK4 as an alternative upstream kinase of LATS1/2 in the Hippo pathway through screening a kinome library. Ripk4 knockout in mice results in activation of Hippo pathway effectors Yap/Taz in the granular layer, which subsequently represses cholesterol biosynthesis. Furthermore, the ablation of Yap/Taz partially rescues skin barrier defects. Mechanistically, RIPK4 directly phosphorylates LATS1/2 after recruiting them into liquid condensates. Disease-derived RIPK4 mutants exhibit defects in LATS1/2 activation either due to impaired kinase activity or disrupted phase separation. Our findings demonstrate that a RIPK4-initiated noncanonical Hippo pathway plays a specific role in epidermal differentiation.

The widely used Radix Astragali (RA) has significant therapeutic effects on cognitive impairment (CI) caused by type 2 diabetes (T2DM). However, the effective active ingredients and the precise mechanism underly RA alleviation of T2DM-induced CI still require further study. In this study, we aim to elucidate whether and how jaranol, a key effective active ingredient in RA, influences CI in db/db mice. We used various online databases and Cytoscape to screen jaranol as the most active ingredient of RA in the treatment of T2DM-induced CI. The fear conditioning experiment, new object recognition (NOR) test, and Morris water maze (MWM) test were conducted to assess the improvement effect of jaranol on CI in diabetic mice. The protein-protein interaction (PPI) network, Cytoscape, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed to identify key genes. The levels of AKT and caspase-3 were determined by Western blotting. The number of surviving hippocampal neurons was verified through Nissl staining. AutoDock was utilized for predicting potential binding sites between jaranol and key genes.As a result, jaranol attenuated CI in db/db mice probably through activation of PI3K-AKT signaling pathway by inhibiting cell apoptosis in hippocampus. Furthermore, A329 near the active site of AKT1 had hydrogen bond with jaranol. In conclusion, we suggest that jaranol may have therapeutic applications in T2DM-induced CI by targeting the PI3K-AKT signaling pathway directly via key sites. Our study provides alternative drugs and potential therapeutic targets for the prevention and treatment of T2DM-induced CI.

Gastric cancer (GC) is one of major global cancers that is highly heterogeneous and has a poor prognosis, especially in cases associated with Helicobacter pylori (H. pylori) infection. H. pylori promote metastasis via mechanisms like endoplasmic reticulum stress (ERS). Telomere-protecting protein 1 (TPP1), a telomere-protecting protein, is overexpressed in GC and linked to poor outcomes. This study investigated TPP1's role in H. pylori-induced ERS and its implications for GC metastasis.We analyzed TPP1 expression using both Starbase data and clinical samples. Functional assays (e.g., migration, invasion, wound healing) were performed in GC cell lines with TPP1 knockdown or overexpression. The interaction between TPP1 and ERS-related proteins was assessed by immunoprecipitation and immunofluorescence. The role of TPP1 in GC metastasis was further validated in a xenograft mouse model. TPP1 was upregulated in GC tissues and cell lines, correlating with poor prognosis. TPP1 knockdown inhibited GC cell metastasis but not proliferation, while TPP1 overexpression enhanced metastasis. H. pylori enhanced TPP1 expression by stabilizing Enhancer of Zeste Homolog 1, which in turn binds to the TPP1 promoter. TPP1 interacted with 78 kDa glucose-regulated protein, disrupting its binding to PKR-like ER kinase and activating ERS. Blocking ERS reversed the pro-metastatic effects of TPP1 overexpression. In vivo, TPP1 knockdown significantly reduced GC metastasis in nude mice xenograft model. TPP1, induced by H. pylori, promoted GC metastasis by enhancing ERS via interaction with glucose-regulated protein. Targeting the TPP1/ERS axis may offer a novel therapeutic strategy for GC.

Caffeine is one of the most popular consumed psychostimulants that mitigates several neurodegenerative diseases. Nevertheless, the roles and molecular mechanisms of caffeine in HIV-associated neurocognitive disorders (HAND) remain largely unclear. Transactivator of transcription (Tat) is a major contributor to the neuropathogenesis of HAND in the central nervous system. In the present study, we determined that caffeine (100 µM) treatment significantly ameliorated Tat-induced decreased astrocytic viability, oxidative stress, inflammatory response and excessive glutamate and ATP release, thereby protecting neurons from apoptosis. Subsequently, SIRT3 was demonstrated to display neuroprotective effects against Tat during caffeine treatment. In addition, Tat downregulated SIRT3 expression via activation of EGR1 signaling, which was reversed by caffeine treatment in astrocytes. Overexpression of EGR1 entirely abolished the neuroprotective effects of caffeine against Tat. Furthermore, counteracting Tat or caffeine-induced differential expression of SIRT3 abrogated the neuroprotection of caffeine against Tat-triggered astrocytic dysfunction and neuronal apoptosis. Taken together, our study establishes that caffeine ameliorates astrocytes-mediated Tat neurotoxicity by targeting EGR1/SIRT3 signaling pathway. Our findings highlight the beneficial effects of caffeine on Tat-induced astrocytic dysfunction and neuronal death and propose that caffeine might be a novel therapeutic drug for relief of HAND.

TNF-α processing inhibitor-1 (TAPI-1) is a known metalloproteinase inhibitor with potential anti-inflammatory effects. However, its anti-cancer effects on esophageal squamous cell carcinoma (ESCC) have not been uncovered. In the present study, the effects of TAPI-1 on ESCC cell viability, migration, invasion, and cisplatin resistance and the underlying molecular mechanisms were investigated in TE-1 and Eca109 cells. To this end, TE-1 and Eca109 cells were exposed to TAPI-1 for indicated time intervals. Cell viability was assessed using cell counting kit-8 assay and apoptosis was evaluated using flow cytometry assay. Migration and invasion were assessed using Transwell assays. Gene expressions were analyzed using quantitative reverse transcription polymerase chain reaction. The activation of NF-κB signaling pathway was elucidated via Western blot and chromatin immunoprecipitation assay. We observed that higher doses (10, 20 μM) of TAPI-1 inhibited ESCC cell viability, while a lower dose (5 μM) of TAPI-1 inhibited ESCC cell migration and invasion and enhanced the chemosensitivity of ESCC cells to cisplatin. Moreover, TAPI-1 suppressed the activation of NF-κB signaling and the target genes expression in the stage of transcription initiation. Furthermore, blocking NF-κB signaling in advance could abolish all the effects of TAPI-1 on ESCC cells. Overall, these results indicated that TAPI-1 impairs ESCC cell viability, migration, and invasion and facilitates cisplatin-induced apoptosis via suppression of NF-κB signaling pathway. TAPI-1 may serve as a potential adjuvant agent with cisplatin for ESCC therapy.

A disintegrin and metalloproteinases (ADAMs) are involved in multiple neurodegenerative diseases. However, the roles and mechanisms of ADAMs in HIV-associated neurocognitive disorder (HAND) remain unclear. Transactivator of transcription (Tat) induces inflammatory response in astrocytes, thereby leading to neuronal apoptosis in the central nervous system. In this study, we determined that ADAM17 expression was upregulated during soluble Tat stimulus in HEB astroglial cells. Inhibition of ADAM17 suppressed Tat-induced pro-inflammatory cytokines production and rescued the astrocytes-derived conditioned media (ACM)-mediated SH-SY5Y neural cells apoptosis. Moreover, ADAM17 mediated Tat-triggered inflammatory response in a NF-κB-dependent manner. Conversely, Tat induced ADAM17 expression via NF-κB signaling pathway. In addition, pharmacological inhibition of NF-κB signaling inhibited Tat-induced inflammatory response, which could be rescued by overexpression of ADAM17. Taken together, our study clarifies the potential role of the ADAM17/NF-κB feedback loop in Tat-induced inflammatory response in astrocytes and the ACM-mediated neuronal death, which could be a novel therapeutic target for relief of HAND.

Bromodomain-containing protein 4 (BRD4) is a reader of histone acetylation and is associated with a variety of diseases. To investigate the expression level of BRD4 in esophageal squamous cell carcinoma (ESCC), its prognostic value and its relationship with immune infiltration. The study included 94 ESCC patients from The Cancer Genome Atlas (TCGA) database and 179 ESCC patients from Affiliated Hospital 2 of Nantong University. The expression levels of proteins in tissue microarray were detected by immunohistochemistry. The prognostic factors were analyzed by Kaplan–Meier curve and univariate and multivariate cox regression. The ESTIMATE website was used to calculate the stromal, immune and ESTIMATE score. CIBERSORT was used to calculate the abundance of immune infiltrates. Spearman and Phi coefficient were used for correlation analysis. The TIDE algorithm was used to predict treatment response to immune checkpoint blockade. BRD4 is up-regulated in ESCC, and high BRD4 expression level is associated with poor prognosis and adverse clinicopathological features. In addition, the monocyte count, systemic inflammatory-immunologic index, platelet-lymphocyte ratio, and monocyte-lymphocyte ratio in the BRD4 high expression level group were higher than in the low expression level group. Finally, we found that BRD4 expression level correlated with immune infiltration and that it was inversely correlated with infiltration of CD8 + T cells. Higher TIDE scores in the BRD4 high expression group than in the low expression group. BRD4 is associated with poor prognosis and immune infiltration in ESCC, and may be a potential biomarker for prognosis and immunotherapy application.

NOTCH receptors are relevant to multiple neurodegenerative diseases. However, the roles and mechanisms of NOTCH receptors in HIV-associated neurocognitive disorder (HAND) remain largely unclear. Transactivator of transcription (Tat) induces oxidative stress and inflammatory response in astrocytes, thereby leading to neuronal apoptosis in the central nervous system. We determined that NOTCH3 expression was upregulated during subtype B or C Tat expression in HEB astroglial cells. Moreover, bioinformatics analysis of the Gene Expression Omnibus (GEO) dataset revealed that NOTCH3 mRNA expression in the frontal cortex tissues of HIV encephalitis patients was higher than that of HIV control patients. Of note, subtype B Tat, rather than subtype C Tat, interacted with the extracellular domain of the NOTCH3 receptor, thus activating NOTCH3 signaling. Downregulation of NOTCH3 attenuated subtype B Tat-induced oxidative stress and reactive oxygen species generation. In addition, we demonstrated that NOTCH3 signaling facilitated subtype B Tat-activated NF-κB signaling pathway, thereby mediating pro-inflammatory cytokines IL-6 and TNF-α production. Furthermore, downregulation of NOTCH3 in HEB astroglial cells protected SH-SY5Y neuronal cells from astrocyte-mediated subtype B Tat neurotoxicity. Taken together, our study clarifies the potential role of NOTCH3 in subtype B Tat-induced oxidative stress and inflammatory response in astrocytes, which could be a novel therapeutic target for the relief of HAND.

Cardiovascular disease (CVD) is the most common cause of death, environmental factors, such as arsenic, playing an important role in the progress of CVD. Vascular endothelial dysfunction (VED) is a crucial early feature for CVD, inorganic arsenic (iAs) can induce autophagy in various cells. However, the role of endothelial autophagy has rarely been studied in VED triggered by arsenic. Total of one hundred and twenty healthy male C57BL/6J mice weighing 18-22 g were randomly divided into an arsenic-exposure group and a control group for 3, 6, 9, and 12 weeks. The results showed that, independent of the exposure period, autophagy markers of p-ATG16L1 levels and Beclin 1 contents in the aortic arch endothelium increased significantly compared with those of the corresponding control group. And different exposure duration decreased NO contents in the serum significantly. Combined with the histological changes that endothelial injury aggravated gradually with the increasing exposure period, suggesting that under exposure to iAs over 9 weeks, VED was remarkably induced, and consistant high levels of endothelial autophagy may play an important role. Additionally, levels of p-AMPK alpha/AMPK alpha increased significantly and p-mTORC1/mTORC1 levels decreased remarkably in the aortic arch endothelium. Then, a NaAsO2-induced-VED in vitro model was used to explore the mechanism of arsenic-induced endothelial autophagy. Similarly, p-AMPK alpha/AMPK alpha level significantly increased, and p-mTORC1/mTORC1 level remarkably decreased induced by 30 mu mol/L NaAsO2 in HUAECs. Further, an AMPK inhibitor (Compound C) pre-treatment prior to arsenic exposure reversed the increased autophagy level, and alleviated the endothelial dysfunction in HUVECs, as shown by the significant increase in the intracellular NO content and the cell vitality. Mechanistically, we revealed that AMPK alpha is active in autophagy of endothelial cells in arsenic-induced VED by regulating mTORC1/p70S6K/ULK1. The present study provide a new promising target for prevention and control arsenicassociated CVD.

Maintenance of energy level to drive movements and material exchange with the environment is a basic principle of life. AMP-activated protein kinase (AMPK) senses energy level and is a major regulator of cellular energy responses. The gamma subunit of AMPK senses elevated ratio of AMP to ATP and allosterically activates the alpha catalytic subunit to phosphorylate downstream effectors. Here, we report that knockout of AMPKγ, but not AMPKα, suppressed phosphorylation of eukaryotic translation elongation factor 2 (eEF2) induced by energy starvation. We identified PPP6C as an AMPKγ-regulated phosphatase of eEF2. AMP-bound AMPKγ sequesters PPP6C, thereby blocking dephosphorylation of eEF2 and thus inhibiting translation elongation to preserve energy and to promote cell survival. Further phosphoproteomic analysis identified additional targets of PPP6C regulated by energy stress in an AMPKγ-dependent manner. Thus, AMPKγ senses cellular energy availability to regulate not only AMPKα kinase, but also PPP6C phosphatase and possibly other effectors.

Fatty acid-binding proteins (FABPs) are relevant to multiple neurodegenerative diseases. However, the roles and mechanisms of FABPs in HIV-associated neurocognitive disorder (HAND) remain yet unclear. In this study, cultured BV-2 microglial cells and HT-22 neuronal cells were used for in vitro experiments and HAND mouse models were constructed through intracerebroventricular injection of lentiviral vectors for in vivo experiments. FABP expression was determined using quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot. The interrelationship between Fabp4 and NF-κB signaling was investigated using chromatin immunoprecipitation, qRT-PCR, and Western blot. The role of Fabp4 in regulating inflammatory response was determined using qRT-PCR, enzyme-linked immunosorbent assay, Western blot, and immunofluorescence staining. Cell viability and apoptosis were analyzed using cell counting kit-8 assay and flow cytometry assay, respectively. Our results suggested an upregulation of Fabp4 expression in the presence of Tat. Tat-induced Fabp4 expression was directly regulated by NF-κB p65, followed by, Fabp4 facilitating Tat-activated NF-κB signaling pathway. We also observed that Fabp4 knockdown in microglial cells significantly suppressed inflammatory response and neuronal apoptosis both in vitro and in vivo. In conclusion, the presence of Tat in microglial cells results in Fabp4 and NF-κB to form a positive feedback loop leading to exacerbate inflammatory response and neuronal apoptosis.

A Disintegrin and metalloproteinase 17 (ADAM17) was proposed to cooperate with NF-κB p65, promoting tumorigenesis and progression of several human cancers. However, the role of ADAM17 remains unknown in human esophageal squamous cell carcinoma (ESCC). In this study, gene expression analyses and cell viability assays suggested that knockdown of ADAM17 suppressed ESCC cell viability. Gene expression analyses and ChIP-qPCR revealed that NF-κB p65 positively regulated ADAM17 expression by binding to the ADAM17 promoter. Rescue experiments showed that overexpression of ADAM17 in NF-κB p65-depleted ESCC cells restored cell viability. In addition, western blot analyses and ChIP-qPCR indicated that ADAM17 was responsible for the persistent activation of NF-κB p65 and contributed to ADAM17 expression in ESCC cells. In conclusion, we propose that ADAM17-activated NF-κB p65 signaling positively regulates ADAM17 expression, and facilitates ESCC cell viability.

Abstract Purpose This study aimed to discuss the effects and relative mechanisms of astragaloside (AST) on diaphragm cell apoptosis in mice with chronic obstructive pulmonary disease (COPD). Materials and methods The mouse models of COPD were established by passive smoking. The pathological changes in lung and diaphragm tissues were observed by hematoxylin and eosin staining and evaluating the number of apoptotic cells of the diaphragm via a terminal deoxynucleotidyl transferase dUTP nick‐end labeling assay. The relative protein expression levels of AKT, p‐AKT, caspase‐3, and caspase‐9 were measured through immunohistochemistry and Western blot assay. Results In comparison with the normal control mice, the pathological change and number of apoptotic cells deteriorated in the lung and diaphragm tissues of COPD model mice. With AST supplement, the pathological change and the number of apoptotic cells significantly improved (p < .05). With AKT inhibitor intervention, the effects of AST treatment disappeared. p‐AKT, caspase‐3, and caspase‐9 protein expression was stimulated in the model group but was depressed in the AST‐treated groups. Conclusion Our in vivo study revealed that AST improved COPD‐induced diaphragm apoptosis by regulating and depressing AKT activities.

We read with interest the recent paper by Zhao et al ,1 which reported that stimulator of interferon genes (STING) signalling alleviated chronic pancreatitis (CP)-induced inflammation and fibrosis. There is increasing evidence that STING activation could lead to inflammatory response and fibrosis. In our opinion, this contention is associated with three major issues: the form of stimulators that activate STING, the degree of STING activation and the type of immune cell lineages activated STING signalling are able to affect its role in the process of disease.Self-DNA released from various types of cells during infection or inflammation may stimulate cyclic guanosine monophosphate–adenosine monophosphate (GMP–AMP)  synthase (cGAS)–STING pathway to different degrees. Zhao et al 1 did not investigate how STING signalling was activated; however, the amount, manner and rate of DNA release under different ways of cell deaths all played important roles in activating downstream pathways. Additionally, recent reports indicated that the extent of DNA oxidation is a key factor in promoting an enhanced inflammatory …

HIV-associated neurocognitive disorders (HANDs) afflict more than half of HIV-1-positive individuals. The transactivator of transcription (Tat) produced by HIV virus elicits inflammatory process and is a major neurotoxic mediator that induce neuron damage during HAND pathogenesis. Activated astrocytes are important cells involved in neuroinflammation and neuronal damage. Purinergic receptors expressed in astrocytes participate in a positive feedback loop in virus-induced neurotoxicity. Here, we investigated that whether P2Y4R, a P2Y receptor subtype, that expressed in astrocyte participates in Tat-induced neuronal death in vitro and in vivo. Soluble Tat protein was performed to determine the expression of P2Y4R and proinflammatory cytokines in astrocytes using siRNA technique via real-time PCR, Western blot, and immunofluorescence assays. Cytometric bead array was used to measure proinflammatory cytokine release. The TUNEL staining and MTT cell viability assay were analyzed for HT22 cell apoptosis and viability, and the ApopTag® peroxidase in situ apoptosis detection kit and cresyl violet staining for apoptosis and death of hippocampal neuron in vivo. We found that Tat challenge increased the expression of P2Y4R in astrocytes. P2Y4R signaling in astrocytes was involved in Tat-induced inflammatory cytokine production via PI3K/Akt- and ERK1/2-dependent pathways. Knockdown of P2Y4R expression significantly reduced inflammatory cytokine production and relieved Tat-mediated neuronal apoptosis in vitro. Furthermore, in vivo challenged with Tat, P2Y4R knockdown mice showed decreased inflammation and neuronal damage, especially in hippocampal CA1 region. Our data provide novel insights into astrocyte-mediated neuron damage during HIV-1 infection and suggest a potential therapeutic target for HANDs.