Histone deacetylase inhibitor chidamide promotes reactivation of latent human immunodeficiency virus by introducing histone acetylation.

Highly active antiretroviral therapy can reduce the human immunodeficiency virus (HIV) viral load in the plasma to undetectable levels. However, because of the presence of latent HIV reservoirs, it is difficult to completely eradicate HIV in infected patients. Our objective was to assess the potency of chidamide, a novel histone deacetylase inhibitor recently approved for cancer treatment by the China Food and Drug Administration, to reactivate latent HIV-1 via histone acetylation. Viral reactivities of chidamide were accessed in 2 latent HIV pseudotype virus cell reporter systems (J-Lat Tat-green fluorescent protein clone A72 and TZM-bl), a latently infected full-length HIV virus cell system (U1/HIV), and resting CD4+ T cells from 9 HIV-infected patients under highly active antiretroviral therapy with undetectable viral load. Chidamide was able to increase HIV expression in each cell line, as evidenced by green fluorescent protein, luciferase activity, and p24, as well as to reactivate latent HIV-1 in primary CD4+ T cells of HIV-infected patients. Histone acetylation adjacent to the HIV promoter in A72 cells was determined by chromatin immunoprecipitation. Chidamide was able to increase histone H3 and H4 acetylation at the HIV promoter. In brief, chidamide induced the reactivation of latent HIV in pseudotype virus reporter cells, latently infected cells, and primary CD4+ T cells, making this compound an attractive option for future clinical trials.

Chidamide, a novel histone deacetylase inhibitor, synergistically enhances gemcitabine cytotoxicity in pancreatic cancer cells.

Pancreatic cancer is a lethal human malignancy with an extremely poor prognosis and urgently requires new therapies. Histone deacetylase inhibitors (HDACIs) represent a new class of anticancer agents and have shown promising antitumor activities in preclinical models of pancreatic cancer. In this study, we sought to determine the antitumor effects of a novel HDACI, chidamide (CS055), in pancreatic cancer cells alone or in combination with gemcitabine. Treatments of BxPC-3 or PANC-1 pancreatic cancer cell lines with chidamide resulted in dose- and time-dependent growth arrest, accompanied by induction of p21 expression. When combined in a sequential schedule, chidamide synergistically enhanced gemcitabine-induced cell growth arrest and apoptosis, accompanied by cooperative downregulation of Mcl-1 and loss of mitochondrial membrane potential (ΔΨm). Chidamide enhanced gemcitabine-induced DNA double-strand breaks and S phase arrest, and abrogated the G2/M cell cycle checkpoint, potentially through suppression of CHK1 expression. Our results suggest that chidamide has a therapeutic potential for treating pancreatic cancer, especially in combination with gemcitabine.

Comparative analysis of co-culture and monoculture models in simulating diabetic neurovascular dysfunction: insights into diabetic retinopathy.

Background: Interaction between retinal vascular endothelial cells and neurons plays a critical role in the pathogenesis of diabetic retinopathy (DR). This study aims to compare an in vitro model over a monoculture model to simulate the neurovascular coupling under the hyperglycemic microenvironment of diabetes. Methods: Rat retinal vascular endothelial cells (RRMECs) and ganglion cells (RGCs) were seeded mono- or co-cultured in a normal (NG, 5.5 mM) and high (HG, 75 mM) glucose concentrations culture medium. Cell viability was detected by the cell counting kit-8 (CCK-8) assay. The ability of migration and lumen formation of RRMECs were determined by scratch wound, transwell migration, and lumen formation assays. The apoptosis index of cells was calculated and detected by propidium iodide (PI)/Hoechst staining. Quantitative and morphological analysis of RGCs was performed through the labeling of RGCs by brain-specific homeobox/POU domain protein 3A (BRN3A) and anti-beta-III tubulin (TUJ1). The gene and protein expression levels of occludin (OCLN) and zonula occludens-1 (ZO-1) were evaluated by quantitative real-time polymerase chain reaction and enzyme-linked immunosorbent assay. Results: The viability, migration, and lumen formation abilities of RRMECs in the HG group significantly increased (P<0.05) in both mono- and co-culture models. Migration and lumen formation abilities of RRMECs in the co-culture with HG were lower than that in the monoculture group (P<0.05). The viability of RGCs cells with HG significantly decreased in both mono- and co-culture models (Pmono<0.001, Pco<0.001), the apoptosis index of RGCs in the co-culture with HG was higher than that in the monoculture (P=0.010). The protein and gene expression of OCLN, and ZO-1 in RRMECs significantly decreased with HG culture medium in both culture models (P<0.05). In the HG group, the protein and gene expression level of the ZO-1 and OCLN of RRMECs significantly decreased in the co-culture model than that in the monoculture model (P<0.05). Conclusion: Compared with mono cell culture, the established co-culture in vitro system for diabetic neurovascular dysfunction can better stimulate the micro-environment of the retinal neurovascular unit.

Clinical Manifestation, Auxiliary Examination Features, and Prognosis of GFAP Autoimmunity: A Chinese Cohort Study.

OBJECTIVE: This paper reports the clinical manifestation and auxiliary examination features of 15 Chinese patients with glial fibrillary acidic protein (GFAP) autoimmunity. METHODS: From June 2016 to December 2019, patients suspected to have neurological autoimmune disease after having their serum and cerebrospinal fluid (CSF) tested for conventional neural antibodies were scanned for additional autoantibodies by immunohistochemistry. Samples that showed a characteristic immunoreactive pattern reminiscent of the GFAP of astrocytes were selected and confirmed by cell-based assay using cells-expressing human GFAPα. RESULTS: A total of 15 patients (eight male and seven female) with a median age at onset of 53 years (range 28-72) were identified as GFAP-IgG-positive. Fourteen cases had GFAP-IgG detected in the CSF, while serum GFAP-IgG was detected in 11 cases. Eleven of the fifteen patients (73.3%) presented with an acute monophasic course, of which 10 (90.9%) had antecedent flu-like symptoms. The predominant phenotype was meningoencephalitis (46.7%), followed by meningoencephalomyelitis in 40% of the cases. The most common clinical features included long tract signs, brainstem symptoms, tremors, headaches, and psychiatric symptoms. Magnetic resonance imaging (MRI) revealed the enhancement of the meninges, the surface of the brainstem, the cerebellum, and the spinal cord as predominant. Inflammatory CSF showed mild lymphocyte-predominant pleocytosis with a median of 51/µL and elevated protein with a median of 87.5 mg/dL. Five patients had coexisting antibodies, including NMDAR-IgG in three patients and Yo and MOG-IgG in one patient each. One patient underwent a stereotactic brain biopsy, and the neuropathology diagnosis was diffuse large B-cell lymphoma. One patient had ovarian teratoma. Eleven of the fifteen (73.3%) patients received both intravenous immunoglobulin and steroids. Among them, three patients also received immunosuppressive agents later. During a two-year follow-up, 9 of the 15 (60%) patients achieved complete clinical remission. CONCLUSIONS: The clinical presentation of GFAP astrocytopathy is heterogeneous. It can be characterized by an acute monophasic course and a chronic relapsing course. Tremors are a prominent clinical manifestation in patients with an acute monophasic course with GFAP-IgG antibodies only. Most patients responded well to immunotherapy. In patients with GFAP autoimmunity, presenting with a chronic relapsing course, one should actively search for immunogenic factors and the culprit antibodies. In the case of primary central nervous system lymphoma, GFAP autoimmunity does not always equate to autoimmune GFAP astrocytopathy.

1,2-Benzothiazine 1,1-dioxide carboxylate derivatives as novel potent inhibitors of aldose reductase.

Due to the importance of aldose reductase (ALR2) as a potential drug target in the treatment of diabetic complications, there are increasing interests in design and synthesis of ALR2 inhibitors. Here, we prepared 1,2-benzothiazine 1,1-dioxide acetic acid derivatives and investigated their inhibition activity. Most of these derivatives were found to be active with IC(50) values ranging from 0.11 µM to 10.42 µM, and compound 8d, 2-[2-(4-bromo-2-fluorobenzyl)-1,1-dioxido-2H-1,2-benzothiazin-4(3H)-ylidene]acetic acid, showed the most potent inhibition activity. Further, SAR and docking studies suggest that in comparison with the α,ß-unsaturated derivatives, the saturated carboxylic acid derivatives had a greater binding affinity with the enzyme and thus an enhanced inhibition activity. Therefore, development of more powerful ARIs based on benzothiazine 1,1-dioxide by stereo-controlled synthesis could be expected.

Molecular cloning and functional analysis of an ERF gene from cotton (Gossypium hirsutum).

Ethylene response factors (ERFs) play important roles in regulating plant biotic and abiotic stress tolerance. In this paper, a new ethylene response factor gene GhERF1 was isolated from cotton. The deduced amino acid sequence of GhERF1 contained an AP2/ERF domain, which shared high similarity with other reported AP2/ERF domains and was most closely related to the B3 subgroup of the ERF subfamily. The particle bombardment assay showed that GhERF1 functioned as an in vivo transcription activator in tobacco cells and was localized in the nuclei of onion epidermis cells. In addition, semi-quantitative RT-PCR revealed that GhERF1 accumulated highly and rapidly when plants were treated with exogenous ethylene, abscisic acid (ABA), high salinity, cold and drought. These results suggested that GhERF1 might be functionally important in acclimation of cotton to stress.

WITHDRAWN: Molecular cloning and functional analysis of an ERFgene from cotton(Gossypiumhirsutum).

The Publisher regrets that this article is an accidental duplication of an article that has already been published in Biochem.Biophys.Acta, doi:10.1016/j.bbagrm.2007.10.003. The duplicate article has therefore been withdrawn.

Diagnostic implications of MOG/AQP4 antibodies in recurrent optic neuritis.

The present study aimed to detect myelin oligodendrocyte glycoprotein (MOG) and aquaporin-4 (AQP4) antibodies in serum specimens of patients with recurrent optic neuritis (RON) through establishing 293 cells with stable expression of MOG and the complete genomic sequence as the substrate using a cell-based assay (CBA). Furthermore, the clinical features of MOG antibody-positive recurrent optic neuritis (MOG-RON) were assessed. A total of 43 RON patients admitted to Beijing Tongren Hospital from December 2014 to May 2015 were enrolled, including 11 males and 32 females. The serum was collected from all patients, and the MOG and AQP4 antibodies were detected via the CBA. According to the results, the 43 patients were divided into four groups, namely the MOG antibody-positive group (n=11), the AQP4 antibody-positive group (n=20), the MOG/AQP4 antibody-positive group (n=1) and the MOG/AQP4 antibody-negative group (n=11). Clinical data were collected and all patients were followed up for 6 months, with parameters observed including the visual acuity, visual field and ocular fundus. The differences in the demographics, clinical features, characteristics of imaging examination, vision at onset and visual function recovery at 6 months after treatment were compared among the different groups. The characteristics of MOG antibody-positive RON were summarized. Of the 43 RON patients, 2.33% was both MOG and AQP4 antibody-positive, 27.91% were MOG antibody-positive. Compared with the AQP4-RON patients, there were relatively less MOG-RON patients (63.6 vs. 95.0%) and the canal segment and intracranial segment of the optic canal were less involved (P<0.05). The visual acuity at onset of MOG-RON was not inferior to that of AQP4-RON, and the visual recovery degree of MOG-RON was better (P<0.05). MOG antibody may be detected in the serum of certain RON patients, which have unique and different characteristics from AQP4 antibody-positive RON patients, so it may be used as a prognostic biomarker for RON. Furthermore, MOG antibody is present in the serum of patients with neuromyelitis optica spectrum disorders and may be a potential biomarker for these conditions.

Valproic acid-mediated myocardial protection of acute hemorrhagic rat via the BCL-2 pathway.

BACKGROUND: Hemorrhage is a major cause of morbidity and mortality among trauma patients. The pathophysiologic changes following acute severe hemorrhage and tissue hypoxia lead to an imbalance of protein acetylation. Histone deacetylase inhibitors (HDACIs) were reported to restore the acetylation imbalance and serve as potential drugs for treating severe hemorrhage. However, the molecular mechanism of HDACI-mediated cytoprotection remains unclear. In this study, we examined the myocardial protective effects and respective mechanism of the HDACI valproic acid (VPA) administered during hemorrhagic and hypoxic stress in vivo and in vitro. METHODS: In vivo, the therapeutic effect of VPA was evaluated in acute severe hemorrhagic rats, and the expressions of BCL-2 signal pathway molecules were observed in rat heart tissues. To explore the molecular mechanism of VPA-mediated myocardial protection, a cobalt chloride (CoCl2)-induced hypoxia model of rat H9c2 cardiomyoblasts was applied to mimic hypoxic injury raised by acute hemorrhage. RESULTS: VPA administration significantly improved the 4-hour survival rate of hemorrhagic animals from 55% to 100% and protected H9c2 cells against CoCl2-induced hypoxic injury at a dose of between 12.5 µM and 100 µM. Increased expression of BCL-2 messenger RNA was observed following VPA treatment in the heart tissues of hemorrhagic rats (approximately 4.9-fold) and in H9c2 cells that survived CoCl2-induced hypoxia (approximately 4.9-fold). Western blot analysis showed a concomitant increase in BCL-2 protein expression and Akt phosphorylation following VPA treatment. The cytoprotective activity of VPA was diminished by triciribine-mediated inhibition of Akt activation and by silencing of BCL-2 gene expression. CONCLUSION: These findings suggest that VPA protects myocardial cells from hemorrhagic and hypoxic stress through the Akt/BCL-2 survival pathway, indicating a potential use of HDACIs for acute severe hemorrhage treatment.

Synergistic antitumor activity of gemcitabine combined with triptolide in pancreatic cancer cells.

Pancreatic cancer is a fatal human malignancy associated with an exceptionally poor prognosis. Novel therapeutic strategies are urgently required to treat this disease. In addition to immunosuppressive activity, triptolide possesses strong antitumor activity and synergistically enhances the antitumor activities of conventional chemotherapeutic drugs in preclinical models of pancreatic cancer. The present study investigated the antitumor effects of triptolide in pancreatic cancer cells, either in combination with gemcitabine, or alone. The pancreatic cancer BxPC-3 and PANC-1 cell lines were treated with triptolide, which resulted in time- and dose-dependent growth arrest. When incorporated into a sequential schedule, triptolide synergistically increased gemcitabine-induced cell growth inhibition and apoptosis, in addition to the cooperative regulation of B-cell lymphoma 2 family proteins and loss of mitochondrial membrane potential. Furthermore, triptolide enhanced gemcitabine-induced S phase arrest and DNA double-strand breaks, possibly through checkpoint kinase 1 suppression. The results of the present study suggest that triptolide has therapeutic potential for the treatment of pancreatic cancer, particularly when administered in combination with gemcitabine.

Chidamide Inhibits Aerobic Metabolism to Induce Pancreatic Cancer Cell Growth Arrest by Promoting Mcl-1 Degradation.

Pancreatic cancer is a fatal malignancy worldwide and urgently requires valid therapies. Previous research showed that the HDAC inhibitor chidamide is a promising anti-cancer agent in pancreatic cancer cell lines. In this study, we elucidate a probable underlying anti-cancer mechanism of chidamide involving the degradation of Mcl-1. Mcl-1 is frequently upregulated in human cancers, which has been demonstrated to participate in oxidative phosphorylation, in addition to its anti-apoptotic actions as a Bcl-2 family member. The pancreatic cancer cell lines BxPC-3 and PANC-1 were treated with chidamide, resulting in Mcl-1 degradation accompanied by induction of Mcl-1 ubiquitination. Treatment with MG132, a proteasome inhibitor reduced Mcl-1 degradation stimulated by chidamide. Chidamide decreased O2 consumption and ATP production to inhibit aerobic metabolism in both pancreatic cancer cell lines and primary cells, similar to knockdown of Mcl-1, while overexpression of Mcl-1 in pancreatic cancer cells could restore the aerobic metabolism inhibited by chidamide. Furthermore, chidamide treatment or Mcl-1 knockdown significantly induced cell growth arrest in pancreatic cancer cell lines and primary cells, and Mcl-1 overexpression could reduce this cell growth inhibition. In conclusion, our results suggest that chidamide promotes Mcl-1 degradation through the ubiquitin-proteasome pathway, suppressing the maintenance of mitochondrial aerobic respiration by Mcl-1, and resulting in inhibition of pancreatic cancer cell proliferation. Our work supports the claim that chidamide has therapeutic potential for pancreatic cancer treatment.

Energy metabolism regulated by HDAC inhibitor attenuates cardiac injury in hemorrhagic rat model.

A disturbance of energy metabolism reduces cardiac function in acute severe hemorrhagic patients. Alternatively, adequate energy supply reduces heart failure and increases survival. However, the approach to regulating energy metabolism conductive to vital organs is limited, and the underlying molecular mechanism remains unknown. This study assesses the ability of histone deacetylase inhibitors (HDACIs) to preserve cardiac energy metabolism during lethal hemorrhagic injury. In the lethally hemorrhagic rat and hypoxic myocardial cells, energy metabolism and heart function were well maintained following HDACI treatment, as evident by continuous ATP production with normal cardiac contraction. Valproic acid (VPA) regulated the energy metabolism of hemorrhagic heart by reducing lactate synthesis and protecting the mitochondrial ultrastructure and respiration, which were attributable to the inhibition of lactate dehydrogenase A activity and the increased myeloid cell leukemia-1 (mcl-1) gene expression, ultimately facilitating ATP production and consumption. MCL-1, the key target of VPA, mediated this cardioprotective effect under acute severe hemorrhage conditions. Our results suggest that HDACIs promote cardioprotection by improving energy metabolism during hemorrhagic injury and could therefore be an effective strategy to counteract this process in the clinical setting.

Human malignant melanoma-derived progestagen-associated endometrial protein immunosuppresses T lymphocytes in vitro.

Progestagen-associated endometrial protein (PAEP) is a glycoprotein of the lipocalin family that acts as a negative regulator of T cell receptor-mediated activation. However, the function of tumor-derived PAEP on the human immune system in the tumor microenvironment is unknown. PAEP is highly expressed in intermediate and thick primary melanomas (Breslow's 2.5mm or greater) and metastatic melanomas, correlating with its expression in daughter cell lines established in vitro. The current study investigates the role of melanoma cell-secreted PAEP protein in regulating T cell function. Upon the enrichment of CD3+, CD4+ and CD8+ T cells from human peripheral blood mononuclear cells, each subset was then mixed with either melanoma-derived PAEP protein or PAEP-poor supernatant of gene-silenced tumor cells. IL-2 and IFN-γ secretion of CD4+ T cells significantly decreased with the addition of PAEP-rich supernatant. And the addition of PAEP-positive cell supernatant to activated lymphocytes significantly inhibited lymphocyte proliferation and cytotoxic T cell activity, while increasing lymphocyte apoptosis. Our result suggests that melanoma cell-secreted PAEP protein immunosuppresses the activation, proliferation and cytotoxicity of T lymphocytes, which might partially explain the mechanism of immune tolerance induced by melanoma cells within the tumor microenvironment.

Activating Na+-K+ ATPase: a potential cardioprotective therapy during early hemorrhagic shock.

Cell volume and resting potential are heavily affected by the activity of Na+-K+ ATPase (NKA, Na+-K+ pump), an essential membrane protein that regulates plasma K+ and Na+ levels. It is generally accepted that the ineffective perfusion of body tissues inhibits NKA activity and that NKA activity and heart failure are closely related. Recently, research has proven that the activation of NKA provides significant cardioprotection against ischemic injury. Based on these data, we propose that NKA stimulation could attenuate the development of heart arrhythmia during the early phase of hemorrhagic shock.

Optimization and establishment of RNA interference-mediated knockdown of the progestagen-associated endometrial protein gene in human metastatic melanoma cell lines.

Progestagen­associated endometrial protein (PAEP), also termed glycodelin, is a 28­kDa glycoprotein of the lipocalin superfamily that is expressed in a variety of tumors, including gynecological tumors, lung cancer and melanoma. To determine the biological functions of the PAEP gene in tumor development and progression, the production of transient and stable PAEP knockdown cell models is required. In the present study, RNA interference technology was used to silence PAEP gene expression in melanoma and transfection was screened for and the conditions were optimized using fluorescence microscopy, flow cytometry, qPCR and western blot analysis. The results of the present study showed that the transient transfection of melanoma cells with 100 nmol/l PAEP siRNA or lentiviral PAEP small hairpin RNA (shRNA) [multiplicity of infection (MOI), 100 pfu/cell] efficiently knocked down target gene expression. To establish stable PAEP knockdown cell lines, melanoma cells were infected with a low MOI (10 pfu/cell) of lentiviral particles expressing PAEP shRNA. Following puromycin screening, the PAEP gene knockdown efficiency was demonstrated to be >80% in 624­Mel and 624.38­Mel cell lines, which was validated by western blot analysis. Therefore, melanoma cell lines with stable knockdown of PAEP were successfully established and may be used as effective cell models to study the biological functions of the PAEP gene in melanoma.