UNASSIGNED: Proliferative vitreoretinopathy (PVR) can cause blindness and the pathogenesis is unclear. Transforming growth factor (TGF)-β-induced epithelial-mesenchymal transition (EMT) of RPE cells is vital. P53 protein 2 (ASPP2) was previously reported to inhibit EMT in PVR rats, but the specific mechanism is unveiled.
UNASSIGNED: TGF-β was used to induce EMT in ARPE-19 cells, and evaluated by immunofluorescence and western blot. ARPE-19 cells were transfected with scrambled/ASPP2-lentivirus, followed by TGF-β treatment. After that, alterations of EMT and autophagy were measured by western blot and transmission electron microscopy. Moreover, TGF-β and ARPE-19 cells treated with scrambled/ASPP2-lentivirus were employed to establish the PVR model via intravitreal injection to SD rats, and retinal changes as well as EMT and autophagy activity were evaluated accordingly.
UNASSIGNED: ASPP2 expression was decreased during TGF-β-induced EMT in ARPE-19 cells. In vitro, EMT and autophagy was activated by TGF-β, which could be partly reversed by ASPP2 upregulation. In vivo, ASPP2 upregulation protected against structural and functional changes in PVR retinas. Additionally, expressions of EMT and autophagy markers in retinas were inhibited by ASPP2 upregulation.
UNASSIGNED: ASPP2 upregulation inhibited the EMT and autophagy process caused by TGF-β in ARPE-19 cells. Correspondingly, upregulation of ASPP2 alleviated intraocular fibrosis and protected visual function in PVR rats.

UNASSIGNED: Acute liver injury (ALI), which is a type of inflammation-mediated hepatocellular injury, is a clinical syndrome that results from hepatocellular apoptosis and hemorrhagic necrosis. Apoptosis stimulating protein of p53-2 (ASPP2) is a proapoptotic member of the p53 binding protein family. However, the role of ASPP2 in the pathogenesis of ALI and its regulatory mechanisms remain unclear.
UNASSIGNED: The expression of ASPP2 were compared between liver biopsies derived from patients with CHB, patients with ALI, and normal controls. Acute liver injury was modelled in mice by administration of D-GalN/LPS. Liver injury was demonstrated by serum transaminases and histological assessment of liver sections. ASPP2-knockdown mice (ASPP2+/-) were used to determine its role in acute liver injury. Mouse bone marrow macrophages (BMMs) were isolated from wildtype and ASPP2+/- mice and stimulated with LPS, and the supernatant was collected to incubate with the primary hepatocytes. Quantitative real-time PCR and western blot were used to analyze the expression level of target.
UNASSIGNED: The expression of ASPP2 was significantly upregulated in the liver tissue of ALI patients and acute liver injury mice. ASPP2+/- mice significantly relieved liver injury through reducing liver inflammation and decreasing hepatocyte apoptosis. Moreover, the conditioned medium (CM) of ASPP2+/- bone marrow-derived macrophages (BMMs) protected hepatocytes against apoptosis. Mechanistically, we revealed that ASPP2 deficiency in BMMs specifically upregulated IL-6 through autophagy activation, which decreased the level of TNF-α to reduce hepatocytes apoptosis. Furthermore, up-regulation of ASPP2 sensitizes hepatocytes to TNF-α-induced apoptosis.
UNASSIGNED: Our novel findings show the critical role of ASPP2 in inflammatory immunoregulatory mechanism of ALI and provide a rationale to target ASPP2 as a refined therapeutic strategy to ameliorate acute liver injury.

Cell polarity is crucial for gastric mucosal barrier integrity and mainly regulated by polarity-regulating kinase partitioning-defective 1b (Par1b). During infection, the carcinogen Helicobacter pylori hijacks Par1b via the bacterial oncoprotein CagA leading to loss of cell polarity, but the precise molecular mechanism is not fully clear. Here we discovered a novel function of the actin-binding protein cortactin in regulating Par1b, which forms a complex with cortactin and the tight junction protein zona occludens-1 (ZO-1). We found that serine phosphorylation at S405/418 and the SH3 domain of cortactin are important for its interaction with both Par1b and ZO-1. Cortactin knockout cells displayed disturbed Par1b cellular localization and exhibited morphological abnormalities that largely compromised transepithelial electrical resistance, epithelial cell polarity, and apical microvilli. H. pylori infection promoted cortactin/Par1b/ZO-1 abnormal interactions in the tight junctions in a CagA-dependent manner. Infection of human gastric organoid-derived mucosoids supported these observations. We therefore hypothesize that CagA disrupts gastric epithelial cell polarity by hijacking cortactin, and thus Par1b and ZO-1, suggesting a new signaling pathway for the development of gastric cancer by Helicobacter.

(1) Background: pancreatic cancer is highly lethal. The role of apoptosis-stimulating protein of p53-2 (ASPP2) in this lethal disease remains unclear. This protein belongs to the ASPP family of p53 interacting proteins. Previous studies in this lab used phosphate-binding tag (Phos-tag) sodium dodecyl sulfate (SDS) polyacrylamide gels and identified a motility upshift of the ASPP family of proteins during mitosis. (2) Purpose: this study expands on previous findings to identify the detailed phosphorylation regulation of ASPP2 during mitosis, as well as the function of ASPP2 in pancreatic cancer. (3) Methods: the Phos-tag technique was used to investigate the phosphorylation mechanism of ASPP2 during mitosis. Phospho-specific antibodies were generated to validate the phosphorylation of ASPP2, and ASPP2-inducible expression cell lines were established to determine the role of ASPP2 in pancreatic cancer. RNA sequencing (RNA-Seq) was used to uncover the downstream targets of ASPP2. (4) Results: results demonstrate that ASPP2 is phosphorylated during mitosis by cyclin-dependent kinase 1 (CDK1) at sites S562 and S704. In vitro and in vivo results show that ASPP2 is required for pancreatic cancer growth. Furthermore, the expressions of yes-associated protein (YAP)-related genes are found to be dramatically altered by ASPP2 depletion. Together, these findings reveal the phosphorylation mechanism of ASPP2 during mitosis. Collectively, results strongly indicate that ASPP2 is a potential target for abating tumor cell growth in pancreatic cancer.

Hepatitis C virus (HCV) infects millions of people worldwide and is a leading cause of liver disease. Despite recent advances in antiviral therapies, viral resistance can limit drug efficacy and understanding the mechanisms that confer viral escape is important. We employ an unbiased interactome analysis to discover host binding partners of the HCV non-structural protein 5A (NS5A), a key player in viral replication and assembly. We identify ASPP2, apoptosis-stimulating protein of p53, as a new host co-factor that binds NS5A via its SH3 domain. Importantly, silencing ASPP2 reduces viral replication and spread. Our study uncovers a previously unknown role for ASPP2 to potentiate HCV RNA replication.

In a previous study, our team found that ASPP2 overexpression increases the sensitivity of liver cancer cells to sorafenib. ASPP2 is an important target in the study of drug therapy for hepatocellular carcinoma. In this study, we demonstrated that ASPP2 altered the response of HepG2 cells to usnic acid (UA) by using mRNA sequencing and CyTOF. CCK8 assay was used to detect cytotoxicity of UA on HepG2 cells. Annexin V-RPE assay, TUNEL assay, and cleaved caspase 3 assay were performed to examine the apoptotic cell death induced by UA. Transcriptomic sequencing and a single-cell mass cytometry were used to analyze the dynamic response of HepG2shcon and HepG2shASPP2 cells to UA treatment. We have demonstrated that UA could inhibit proliferation in HepG2 cells in a concentration-dependent manner. Apoptotic cell death was significantly induced by UA in HepG2 cells, while knocking down ASPP2 could increase the resistance of HepG2 cells to UA. Data from mRNA-Seq indicated that knockout of ASPP2 in HepG2 cells affected cell proliferation, cycle, and metabolism. ASPP2 knockdown resulted in increased stemness and decreased apoptosis of HepG2 cells under the action of UA. CyTOF analysis confirmed the above results, ASPP2 knockdown increased oncoproteins in HepG2 cells and altered response patterns of HepG2 cells to UA. Our data suggested that the natural compound UA could inhibit liver cancer HepG2 cells; meanwhile, ASPP2 knockdown could affect response patterns of HepG2 cells to UA. The above results indicate that ASPP2 could be a research target in the chemoresistance of liver cancer.

Abnormal energy metabolism is one of the characteristics of tumours. In the last few years, more and more attention is being paid to the role and regulation of tumour aerobic glycolysis. Cancer cells display enhanced aerobic glycolysis, also known as the Warburg effect, whereby tumour cells absorb glucose to produce a large amount of lactic acid and energy under aerobic conditions to favour tumour proliferation and metastasis. In this study, we report that the haploinsufficient tumour suppressor ASPP2, can inhibit HCC growth and stemness characteristics by regulating the Warburg effect through the WNT/β-catenin pathway. we performed glucose uptake, lactate production, pyruvate production, ECAR and OCR assays to verify ASPP2 can inhibit glycolysis in HCC cells. The expression of ASPP2 and HK2 was significantly inversely correlated in 80 HCC tissues. Our study reveals downregulation of ASPP2 can promote the aerobic glycolysis metabolism pathway, increasing HCC proliferation, glycolysis metabolism, stemness and drug resistance. This ASPP2-induced inhibition of glycolysis metabolism depends on the WNT/β-catenin pathway. ASPP2-regulated Warburg effect is associated with tumour progression and provides prognostic value. and suggest that may be promising as a new therapeutic strategy in HCC.

Growing evidence indicates that lipid metabolism disorders and gut microbiota dysbiosis were related to the progression of non-alcoholic fatty liver disease (NAFLD). Apoptosis-stimulating p53 protein 2 (ASPP2) has been reported to protect against hepatocyte injury by regulating the lipid metabolism, but the mechanisms remain largely unknown. In this study, we investigate the effect of ASPP2 deficiency on NAFLD, lipid metabolism and gut microbiota using ASPP2 globally heterozygous knockout (ASPP2+/-) mice.
ASPP2+/- Balb/c mice were fed with methionine and choline deficient diet for 3, 10 and 40 day to induce an early and later-stage of NAFLD, respectively. Fresh fecal samples were collected and followed by 16S rRNA sequencing. HPLC-MRM relative quantification analysis was used to identify changes in hepatic lipid profiles. The expression level of innate immunity-, lipid metabolism- and intestinal permeability-related genes were determined. A spearman\'s rank correlation analysis was performed to identify possible correlation between hepatic medium and long-chain fatty acid and gut microbiota in ASPP2-deficiency mice.
Compared with the WT control, ASPP2-deficiency mice developed moderate steatosis at day 10 and severe steatosis at day 40. The levels of hepatic long chain omega-3 fatty acid, eicosapentaenoic (EPA, 20:5 n-3) and docosahexaenoic (DHA, 22:6 n-3), were decreased at day 10 and increased at day 40 in ASPP+/- mice. Fecal microbiota analysis showed significantly increased alpha and beta diversity, as well as the composition of gut microbiota at the phylum, class, order, family, genus, species levels in ASPP2+/- mice. Moreover, ASPP-deficiency mice exhibited impaired intestinal barrier function, reduced expression of genes associated with chemical barrier (REG3B, REG3G, Lysozyme and IAP), and increased expression of innate immune components (TLR4 and TLR2). Furthermore, correlation analysis between gut microbiota and fatty acids revealed that EPA was significantly negatively correlated with Bifidobacterium family.
Our findings suggested that ASPP2-deficiency promotes the progression of NAFLD, alterations in fatty acid metabolism and gut microbiota dysbiosis. The long chain fatty acid EPA was significantly negatively correlated with Bifidobacterial abundance, which is a specific feature of NAFLD in ASPP2-deficiency mice. Totally, the results provide evidence for a mechanism of ASPP2 on dysregulation of fatty acid metabolism and gut microbiota dysbiosis.

P53 Apoptosis Stimulating Protein 2 (ASPP2) is confirmed to participate in cellular activities including apoptosis, proliferation, autophagy, injury and so on. However, the role of ASPP2 in Hepatitis B virus (HBV) infection has not been reported in detail. The study explored the role of ASPP2 in HBV induced chronic liver damage.
Transcriptome profiling of ASPP2-konckdown mouse liver were analyzed by RNA-sequencing. HBV-ASPP2-knockdown mice was the hybrid offspring of HBV transgenic mice and ASPP2 knockdown mice. Liver tissues were taken for the experiments such as western Blot (WB), PCR, Hematoxylin and Eosin (HE), Immunohistochemistry and high throughput sequencing of transcriptome.
Pathological and transcriptomic analysis of liver tissue from ASPP2 knockdown vs con mice showed that after ASPP2 knockdown, the pathological changes in the liver tissue of mice were not significant, but transcriptomics showed obvious changes in immune system process, and response to stimulus, metabolism, Human Diseases and other directions etc. In the HBV-ASPP2-knockdown mice, liver tissue HE staining found less cell swelling and necrosis foci; F4/80 and MPO staining showed less inflammatory cell infiltration; serum ALT and AST decreased than the HBV-ASPP2-con mice. Transcriptome results showed significantly changed in HBV-ASPP2-knockdown mice including immune system process, inflammatory response, and innate immune response etc. Further comparison of the two transcriptomes yielded 9 identical pathways related to inflammatory and cell injury. The PPAR pathway was verified, and found that the increase of PPARγ caused by the reduction of ASPP2 is likely to be the reason for the reduction of HBV-related liver injury. The expression of PPARγ was then analyzed by transcriptome and PCR, it was found that in the absence of HBV, ASPP2 knockdown resulted in a mild decrease in PPARγ, and in the presence of HBV infection, ASPP2 knockdown resulted in a marked increase in PPARγ.In addition, this study found that high expression of ASPP2 had opposite effects on HCC (HBV-none) and HCC (HBV-yes).
This study demonstrated that reduction of ASPP2 reduces HBV-induced hepatocyte damage during chronic HBV infection. This phenomenon is related to the different regulation of PPARγ by ASPP2 in the presence or absence of HBV stimulation.

Background: Though ASPP2 plays an important role in regulating cell apoptosis and autophagy in case of liver injury, there remains a lack of clarity on the molecular mechanism of ASPP2 regulating autophagy and apoptosis. Methods: A hepatocyte injury model was constructed using HL7702 cell line and TNF-α. The cells were treated by ASPP2 overexpression adenovirus or short hairpin RNA lentivirus and endoplasmic reticulum stress (ERS) or the mammalian target of rapamycin (mTOR) inhibitor or agonist, respectively. The autophagy was detected by means of western blot and Green fluorescent protein-labeled- Microtubule-associated protein light chain 3 (GFP-LC3) plasmid transfection, while the apoptosis was detected through western blot, flow cytometry and TUNEL assay. Besides, the proteins related to ERS and mTOR were detected by western blot. Results: The low level of ASPP2 expression was accompanied by high-level autophagy and low-level apoptosis and vice versa in case of hepatocyte injury induce by TNF-α. By upregulating the proteins related to mTORC1 and ERS, ASPP2 induced apoptosis but inhibited autophagy. However, the effect of ASPP2 on autophagy and apoptosis can be reversed by the use of mTORC1 and ERS interfering agent, which indicates that ASPP2 regulated autophagy and apoptosis through mTORC1and ERS pathway. ERS treatment made no difference to the expression of ASPP2 and mTOR-related proteins, which suggests the possibility that the regulation of ERS on apoptosis and autophagy could occur in the downstream of ASPP2 and mTOR. Conclusion: ASPP2 could inhibit autophagy and induce apoptosis through mTORC1-ERS pathway in case of the hepatocyte injury induce by TNF-α. The role of ASPP2-mTORC1-ERS axis was verified in hepatocyte injury, which suggests the possibility that ASPP2 is an important regulatory molecule for the survival and death of hepatocyte.