Disruption of gut homeostasis by opioids accelerates HIV disease progression

Cumulative studies during the past 30 years have established the correlation between opioid abuse and human immunodeficiency virus (HIV) infection. Further studies also demonstrate that opioid addiction is associated with faster progression to AIDS in patients. Recently, it was revealed that disruption of gut homeostasis and subsequent microbial translocation play important roles in pathological activation of the immune system during HIV infection and contributes to accelerated disease progression. Similarly, opioids have been shown to modulate gut immunity and induce gut bacterial translocation. This review will explore the mechanisms by which opioids accelerate HIV disease progression by disrupting gut homeostasis. Better understanding of these mechanisms will facilitate the search for new therapeutic interventions to treat HIV infection especially in opioid abusing population

The role of the gut microbiome and microbial metabolism in mediating opioid-induced changes in the epigenome

The current opioid pandemic is a major public health crisis in the United States, affecting millions of people and imposing significant health and socioeconomic burdens. Preclinical and clinical research over the past few decades has delineated certain molecular mechanisms and identified various genetic, epigenetic, and environmental factors responsible for the pathophysiology and comorbidities associated with opioid use. Opioid use-induced epigenetic modifications have been identified as one of the important factors that mediate genetic changes in brain regions that control reward and drug-seeking behavior and are also implicated in the development of tolerance. Recently, it has been shown that opioid use results in microbial dysbiosis, leading to gut barrier disruption, which drives systemic inflammation, impacting the perception of pain, the development of analgesic tolerance, and behavioral outcomes. In this review, we highlight the potential role of microbiota and microbial metabolites in mediating the epigenetic modifications induced by opioid use

Morphine potentiates glucocorticoid receptor translocation in neuronal cells

Background: The hypothalamic-pituitary-adrenal (HPA) axis plays a central role in regulating signaling by glucocorticoid receptor which is expressed in almost all cells. Adrenocorticotropin hormone (ACTH) and β-endorphin both of which are derived through processing of pro-opiomelanocortin (POMC) pro-hormone are secreted from anterior pituitary under stressed conditions. ACTH released into circulation regulates the release of glucocorticoids from adrenal gland. Glucocorticoids cause profound suppression of functional activity of HPA axis as negative feedback control. The endogenous opioids acting primarily at mu opioid receptor inhibit activity of HPA axis and thus release ACTH and β-endorphin from anterior pituitary. Furthermore, there are enough reports to support that glucocorticoids regulate mu opioid receptor expression through GRE binding specially in mouse where it has already been shown that promoter region of mouse mu opioid receptor not delta or kappa opioid receptor contains a glucocorticoid-response element (GRE). The glucocorticoid receptor is a member of steroid-hormone receptor family of proteins. It binds to glucocorticoids with high affinity. In inactive state, the GR complexes with chaperones like heat shock proteins 70 (Hsp70) and 90 (Hsp90) and immunophilins and their co-chaperones making GR more accessible to ligand binding. After ligand binding the GR is activated and chaperones and co-chaperones are reshuffled with GR to be translocated to nucleus where the GR homodimerize and binds to GRE in promoter region. The resulting complex recruits either co-activator or co-repressor proteins that modify the structure of chromatin thereby facilitating or inhibiting assembly of the basal transcription machinery and the initiation of transcription by RNA polymerase II.Aim: Acute and chronic morphine treatments have been shown to result in marked induction of Hsp70 messenger RNA expression. At the same time Hsp70 is also an integral part of GR assembly in inactive and active state. We are therefore hypothesizing that mu opioid receptor crosstalk with glucocorticoid receptor, and this interaction is in part, mediated by Hsp70 acting as adaptor protein.Method: Murine N2A cells were either stably transfected with HA-tagged mu opioid receptor and/or HSP70. These cells were treated with morphine sulphate (1uM) for 5 hours followed by treatment with different concentrations of corticosterone (GC) for 30 minutes. We confirmed their crosstalk by immunoprecipitation and co-immunoprecipitation experiments. Further, nuclear translocation of glucocorticoid receptor was monitored in immunoblots.Results and Discussion: Morphine treatment resulted in increased expression of Hsp70. Pull-down assays showed the interaction between mu opioid receptor and glucocorticoid receptor. These two proteins also interacted with Hsp70; a chaperone protein known to interact with glucocorticoid receptor. Morphine treatment potentiated glucocorticoid receptor translocation to the nucleus which was further potentiated by Hsp70 overexpression. These results confirm the crosstalk between MOR and GR. For future studies, we would study this interaction in immune cells like J774 (alveolar macrophages) and CRL2019 cells (peritoneal macrophages)

Replication in Drosophila chromosomes. Part IV. Patterns of chromosomal replication in salivary gland polytene nuclei of Drosophila nasuta

Replication in polytene nuclei, of late third instar larvae and early prepupae of D. nasuta has been studied by autoradiography of squash preparations of salivary glands following a 10 min in vitro pulse of 3H-thymidine. A reference photomap of polytene chromosomes of D. nasuta is also presented As described earlier in D. kikkawai [Roy and Lakhotia, Indian J exp Biol, 17 (I 979) 231], in D. nasuta also 3 Categories of early-S 3H-thymidine labelling patterns (low, mid, and heavy, interband type) are seen in high frequency in late larval stages but not in early prepupae when the conventional discontinuous (2D and I D) labelling patterns are predominant. In some of the low interband type labelled nuclei, only one puff site, 48A on 2R, is seen to be labelled and this particular puff also remains labelled with a much higher silver grain density in comparison with 4 other puff sites on 2R, in all labelling patterns. Most of the other puffs are unlabelled in late-S patterns. It is suggested that in polytene nuclei of late third instar larvae of D. nasuta, a polytene S-period is initiated by DNA synthesis only at the 48A puff, the other disperse regions (puffs and interbands) start replicating later in a sequential manner followed by initiation of replication of band regions, The 48A puff seems to have an unusually extended period of DNA synthesis and shows striking similarity with the E-11E puff of D. kikkawai (Roy and Lakhotia, 1979). The patterns of replication of X-.chromosome in male and female polytene nuclei of D. nasuta in the early stages of polytene-S period have also been examined. The observations suggest that in D. nasuta the replication of different sites on male X is initiated slightly later than some sites on autosornes or on female X's. However after this initial delay the male X becomes faster replicating from the heavy interband labelling stage onwards and as in other species, completes its replication cycle in late-S (ID type pattern) before many autosomal or female X chromosomal sites

Effect of osmolytes and chaperone-like action of p-protein on folding of nucleocapsid protein of Chandipura virus

Amino acid sequences of nucleocapsid proteins are mostly conserved among different rhabdoviruses. The protein plays a common functional role in different RNA viruses by enwrapping the viral genomic RNA in an RNase-resistant form. Upon expression of the nucleocapsid protein alone in COS cells and in bacteria, it forms large insoluble aggregates. In this work, we have reported for the first time the full-length cloning of the N gene of Chandipura virus and its expression in Escherichia coli in a soluble monomeric form and purification using nonionic detergents. The biological activity of the soluble recombinant protein has been tested, and it was found to possess efficient RNA-binding ability. The state of aggregation of the recombinant protein was monitored using light scattering. In the absence of nonionic detergents, it formed large aggregates. Aggregation was significantly reduced in the presence of osmolytes such asd-sorbitol. Aggregate formation was suppressed in the presence of another viral product, phosphoprotein P, in a chaperone-like manner. Both the osmolyte and phosphoprotein P also suppressed aggregation to a great extent during refolding from a guanidine hydrochloride-denatured form. The function of the phosphoprotein and osmolyte appears to be synergistic to keep the N-protein in a soluble biologically competent form in virus-infected cells

Synchrony of replication in sister salivary glands of Drosophila kikkawai

Intergland synchrony of replication in the larval salivary glands of D. kikkawai bas been studied by 3H-thymidine pulse labelling and very light squashing. It is observed that there is a striking synchrony of replication between the 2 sister glands with respect to the position of the replicating nuclei and the frequency of different labelling patterns. There is also considerable synchrony within a gland where a group of neighbouring nuclei show similar kind of labelling. These observations suggest that the replication cycles of different polytene nuclei in the two sister salivary glands of a Iarva are developmentally determined

PPARγ gene C161T substitution alters lipid profile in Chinese patients with coronary artery disease and type 2 diabetes mellitus

<p>Abstract</p> <p>Background</p> <p>Peroxisome proliferator-activated receptor γ (PPARγ) is a ligand-activated transcription factor, which regulates gene expression of the key proteins involved in lipid metabolism, vascular inflammation, and proliferation. PPARγ may contribute to attenuating atherogenesis and postangioplasty restenosis. PPARγ C161→T substitution is associated with a reduced risk of coronary artery disease (CAD). Whether or not the gene substitution alters the risk of CAD in type 2 diabetes mellitus (T2DM) patients remains unclear.</p> <p>Methods</p> <p>A total of 556 unrelated subjects from a Chinese Han population, including 89 healthy subjects, 78 CAD patients, 86 T2DM patients, and 303 CAD combined with T2DM patients, were recruited to enroll in this study. PPARγC161→T gene polymorphism was determined by polymerase chain reaction and restriction fragment length polymorphisms. Plasma levels of lipoproteins, apolipoproteins, glucose, and insulin were measured by ELISA or radioimmunoassay (RIA). The coronary artery lesions were evaluated by coronary angiography.</p> <p>Results</p> <p>The frequency of the 161T allele in CAD, T2DM, and CAD combined with T2DM patients was similar to that observed in the healthy control group. However, in CAD combined with T2DM patients, the group with angiographically documented moderate stenoses had a higher frequency of the 161T allele in comparison to the group with severe stenoses (P < 0.05). Moreover, in CAD with T2DM patients, the triglyceride levels and apoB in CC homozygote carriers were significantly higher than those in "T" allele carriers.</p> <p>Conclusions</p> <p>PPARγC161→T genotypes weren't significantly associated with the risk of CAD, but were markedly correlated with severity of disease vessels in patients with CAD and T2DM. Furthermore, PPARγC161→T substitution was associated with an altered adipose, but not glucose metabolism. These results indicate that the PPARγ C161→T polymorphism may reduce the risk of severe atherogenesis by modulation of adipose metabolism, especially triglycerides and apoB, in Chinese patients with CAD and T2DM.</p

Oncostatin M promotes excitotoxicity by inhibiting glutamate uptake in astrocytes: implications in HIV-associated neurotoxicity

Background: Elevated levels of oncostatin M (OSM), an interleukin-6 cytokine family member, have been observed in HIV-1-associated neurocognitive disorders (HAND) and Alzheimer's disease. However, the function of OSM in these disease conditions is unclear. Since deficient glutamate uptake by astrocytes is instrumental in HAND-associated neurotoxicity, we hypothesized that OSM impairs glutamate uptake in astrocytes and thereby promotes neuronal excitotoxicity. Methods: Primary cultures of mouse cortical astrocytes, neurons, microglia, and BV2 cell line were used. The expression of glutamate transporters (GLAST/EAAT1 and GLT-1/EAAT2) was investigated using real-time PCR and Western blot, and their activity was assessed by measuring H-3-D-aspartate uptake. Neuronal toxicity was measured using the colorimetric MTT (3-(4,5-dimethylthiazol-2-yl-) 2,5-diphenyltetrazolium bromide) assay and immunocytochemistry. A chimeric HIV-1 that infects murine cells (EcoHIV/NL4-3-GFP virus (EcoHIV)) was used to investigate whether the virus induces OSM, OSM receptor (OSMR)-beta, glycoprotein 130 (gp130), GLT-1, GLAST (mRNA and protein), and OSM release (ELISA) in cultured BV2 cells, primary microglia, or astrocytes. Statistical analyses of the data were performed using one-way ANOVA (to allow multiple comparisons) and two-tailed Student's t test. Results: OSM treatment (10 ng/mL) time-dependently reduced GLAST and GLT-1 expression and inhibited 3H-D-aspartate uptake in cultured astrocytes in a concentration-dependent manner, an effect prevented by the Janus kinase (JAK)/signal transducers and activators of transcription (STAT) 3 inhibitor AG490. Down-regulation of astrocytic glutamate transport by OSM resulted in NMDA receptor-dependent excitotoxicity in cortical neurons. Infection with EcoHIV induced OSM gene expression and protein release in BV2 cells and microglia, but not in astrocytes. Conversely, EcoHIV caused a fivefold increase in OSMR-beta mRNA (but not gp130) and protein in astrocytes, but not in microglia, which did not express OSMR-beta protein. Finally, astrocytic expression of GLAST gene was unaffected by EcoHIV, whereas GLT-1 mRNA was increased by twofold. Conclusions: We provide first evidence that activation of JAK/STAT3 signaling by OSM inhibits glutamate uptake in astrocytes, which results in neuronal excitotoxicity. Our findings with EcoHIV suggest that targeting OSMR-beta signaling in astrocytes might alleviate HIV-1-associated excitotoxicity

Linking the gut microbiome to microglial activation in opioid use disorder

Substance use disorder (SUD) is a physical and psychological disorder globally prevalent today that has resulted in over 107,000 drug overdose deaths in 2021 in the United States alone. This manuscript reviews the potential relationship between opioid use disorder (OUD), a prevalent subset of SUD, and the microglia, the resident macrophages of the central nervous system (CNS), as they have been found to become significantly more activated during opioid exposure. The inflammatory response mediated by the microglia could contribute to the pathophysiology of SUDs, in particular OUD. Further understanding of the microglia and how they respond to not only signals in the CNS but also signals from other areas of the body, such as the gut microbiome, could explain how the microglia are involved in drug use. Several studies have shown extensive communication between the gut microbiome and the microglia, which may be an important factor in the initiation and development of OUD. Particularly, strategies seeking to manipulate and restore the gut microbiome have been shown to reduce microglial activation and attenuate inflammation. In this review, we discuss the evidence for a link between the microglia and OUD and how the gut microbiome might influence microglial activation to drive the disorder and its associated behaviors. Understanding this connection between microglia and the gut microbiome in the context of drug use may present additional therapeutic targets to treat the different stages of drug use

HIV, opioid use, and alterations to the gut microbiome: elucidating independent and synergistic effects

BackgroundThe microbiome is essential to immune development, defense against pathogens, and modulation of inflammation. Microbial dysbiosis has been reported in various diseases including human immunodeficiency virus (HIV) and opioid use disorder (OUD). Notably, people living with HIV (PLWH) have been reported to both have higher rates of OUD and use opioids at higher rates than the general public. Thus, studying gut microbial alterations in people living with HIV and with OUD could elucidate mechanisms pertaining to how these conditions both shape and are shaped by the microbiome. However, to date few studies have investigated how HIV and OUD in combination impact the microbiome.Aim of reviewHere, we review previous studies outlining interactions between HIV, opioid use, and microbial dysbiosis and describe attempts to treat this dysbiosis with fecal microbial transplantation, probiotics, and dietary changes.Key scientific concepts of reviewWhile the limited number of studies prevent overgeneralizations; accumulating data suggest that HIV and opioid use together induce distinct alterations in the gut microbiome. Among the three existing preclinical studies of HIV and opioid use, two studies reported a decrease in Lachnospiraceae and Ruminococcaceae, and one study reported a decrease in Muribaculaceae in the combined HIV and opioid group relative to HIV-alone, opioid-alone, or control groups. These bacteria are known to modulate immune function, decrease colonic inflammation, and maintain gut epithelial barrier integrity in healthy individuals. Accordingly, modulation of the gut microbiome to restore gut homeostasis may be attempted to improve both conditions. While mixed results exist regarding treating dysbiosis with microbial restoration in PLWH or in those with opioid dependency, larger well-defined studies that can improve microbial engraftment in hosts hold much promise and should still be explored