Gi Protein Research Articles

Measuring Smoothened (SMO)-Mediated Activation of the Gi Protein.

The oncoprotein Smoothened (SMO) can transduce the Hedgehog signal from the tumor suppressor Patched-1 (PTCH1) to glioma-associated-oncogene (Gli) transcription factors. Previous studies have shown that SMO is a G-protein-coupled receptor (GPCR) of the Frizzled-class (class-F) that can activate Gi family of heterotrimeric G proteins. Here, we describe [35S]-GTPγS assay using SMO cell membranes and purified Gi protein to measure the level of Gi protein activation following the activation of SMO by agonists.

Structures and Agonist Binding Sites of Bitter Taste Receptor TAS2R5 Complexed with Gi Protein and Validated against Experiment.

Bitter taste receptors (TAS2Rs) function in taste perception, but are also expressed in many extraoral tissues, presenting attractive therapeutic targets. TAS2R5s expressed on human airway smooth muscle cells can induce bronchodilation for treating asthma and other obstructive diseases. But TAS2R5s display low agonist affinity and the lack of a 3D structure has hindered efforts to design more active ligands. We report the structure of the activated TAS2R5 coupled to the Gi protein and bound to each of 19 agonists, using computational approaches. These agonists bind to two polar residues in TM3 that are unique for TAS2R5 among 25 TAS2R subtypes. Our predicted results correlate well with experimental results of agonist-receptor signaling coefficients, providing validation of the predicted structure. These results provide highly specific data on how agonists activate TAS2R5, how modifications of ligand structure alter receptor activation, and a guide to structure-based drug design.

Specific Engineered G Protein Coupling to Histamine Receptors Revealed from Cellular Assay Experiments and Accelerated Molecular Dynamics Simulations.

G protein-coupled receptors (GPCRs) are targets of extracellular stimuli and hence occupy a key position in drug discovery. By specific and not yet fully elucidated coupling profiles with α subunits of distinct G protein families, they regulate cellular responses. The histamine H2 and H4 receptors (H2R and H4R) are prominent members of Gs- and Gi-coupled GPCRs. Nevertheless, promiscuous G protein and selective Gi signaling have been reported for the H2R and H4R, respectively, the molecular mechanism of which remained unclear. Using a combination of cellular experimental assays and Gaussian accelerated molecular dynamics (GaMD) simulations, we investigated the coupling profiles of the H2R and H4R to engineered mini-G proteins (mG). We obtained coupling profiles of the mGs, mGsi, or mGsq proteins to the H2R and H4R from the mini-G protein recruitment assays using HEK293T cells. Compared to H2R–mGs expressing cells, histamine responses were weaker (pEC50, Emax) for H2R–mGsi and –mGsq. By contrast, the H4R selectively bound to mGsi. Similarly, in all-atom GaMD simulations, we observed a preferential binding of H2R to mGs and H4R to mGsi revealed by the structural flexibility and free energy landscapes of the complexes. Although the mG α5 helices were consistently located within the HR binding cavity, alternative binding orientations were detected in the complexes. Due to the specific residue interactions, all mG α5 helices of the H2R complexes adopted the Gs-like orientation toward the receptor transmembrane (TM) 6 domain, whereas in H4R complexes, only mGsi was in the Gi-like orientation toward TM2, which was in agreement with Gs- and Gi-coupled GPCRs structures resolved by X-ray/cryo-EM. These cellular and molecular insights support (patho)physiological profiles of the histamine receptors, especially the hitherto little studied H2R function in the brain, as well as of the pharmacological potential of H4R selective drugs.

Structures of signaling complexes of lipid receptors S1PR1 and S1PR5 reveal mechanisms of activation and drug recognition.

Sphingosine-1-phosphate (S1P) is an important bioactive lipid molecule in cell membrane metabolism and binds to G protein-coupled S1P receptors (S1PRs) to regulate embryonic development, physiological homeostasis, and pathogenic processes in various organs. S1PRs are lipid-sensing receptors and are therapeutic targets for drug development, including potential treatment of COVID-19. Herein, we present five cryo-electron microscopy structures of S1PRs bound to diverse drug agonists and the heterotrimeric Gi protein. Our structural and functional assays demonstrate the different binding modes of chemically distinct agonists of S1PRs, reveal the mechanical switch that activates these receptors, and provide a framework for understanding ligand selectivity and G protein coupling.

Allosteric modulators enhance agonist efficacy by increasing the residence time of a GPCR in the active state

Much hope in drug development comes from the discovery of positive allosteric modulators (PAM) that display target subtype selectivity and act by increasing agonist potency and efficacy. How such compounds can allosterically influence agonist action remains unclear. Metabotropic glutamate receptors (mGlu) are G protein-coupled receptors that represent promising targets for brain diseases, and for which PAMs acting in the transmembrane domain have been developed. Here, we explore the effect of a PAM on the structural dynamics of mGlu2 in optimized detergent micelles using single molecule FRET at submillisecond timescales. We show that glutamate only partially stabilizes the extracellular domains in the active state. Full activation is only observed in the presence of a PAM or the Gi protein. Our results provide important insights on the role of allosteric modulators in mGlu activation, by stabilizing the active state of a receptor that is otherwise rapidly oscillating between active and inactive states.

An ionic lock and a hydrophobic zipper mediate the coupling between an insect pheromone receptor BmOR3 and downstream effectors

Pheromone receptors (PRs) recognize specific pheromone compounds to guide the behavioral outputs of insects, which are the most diverse group of animals on earth. The activation of PRs is known to couple to the calcium permeability of their coreceptor (Orco) or putatively with G proteins; however, the underlying mechanisms of this process are not yet fully understood. Moreover, whether this transverse seven transmembrane domain (7TM)-containing receptor is able to couple to arrestin, a common effector for many conventional 7TM receptors, is unknown. Herein, using the PR BmOR3 from the silk moth Bombyx mori and its coreceptor BmOrco as a template, we revealed that an agonist-induced conformational change of BmOR3 was transmitted to BmOrco through transmembrane segment 7 from both receptors, resulting in the activation of BmOrco. Key interactions, including an ionic lock and a hydrophobic zipper, are essential in mediating the functional coupling between BmOR3 and BmOrco. BmOR3 also selectively coupled with Gi proteins, which was dispensable for BmOrco coupling. Moreover, we demonstrated that trans-7TM BmOR3 recruited arrestin in an agonist-dependent manner, which indicates an important role for BmOR3–BmOrco complex formation in ionotropic functions. Collectively, our study identified the coupling of G protein and arrestin to a prototype trans-7TM PR, BmOR3, and provided important mechanistic insights into the coupling of active PRs to their downstream effectors, including coreceptors, G proteins, and arrestin.

CHARMM Force-Field Parameters for Morphine, Heroin, and Oliceridine, and Conformational Dynamics of Opioid Drugs.

Opioid drug binding to specialized G protein-coupled receptors (GPCRs) can lead to analgesia upon activation via downstream Gi protein signaling and to severe side effects via activation of the β-arrestin signaling pathway. Knowledge of how different opioid drugs interact with receptors is essential, as it can inform and guide the design of safer therapeutics. We performed quantum and classical mechanical computations to explore the potential energy landscape of four opioid drugs: morphine and its derivatives heroin and fentanyl and for the unrelated oliceridine. From potential energy profiles for bond twists and from interactions between opioids and water, we derived a set of force-field parameters that allow a good description of structural properties and intermolecular interactions of the opioids. Potential of mean force profiles computed from molecular dynamics simulations indicate that fentanyl and oliceridine have complex energy landscapes with relatively small energy penalties, suggesting that interactions with the receptor could select different binding poses of the drugs.

In Vivo Dissection of Two Intracellular Pathways Involved in the Spinal Oxytocin-Induced Antinociception in the Rat

Behavioral and electrophysiological data show that at the spinal level, oxytocin inhibits pain transmission by activation of oxytocin receptors (OTRs). Canonically, OTRs are coupled to Gq proteins, which induce a rise of intracellular Ca2+ by activating the phospholipase C (PLC). However, in vitro data showed that OTRs cause a plethora of intracellular events, some related to the activation of Gi proteins. Using a behavioral approach, we analyzed the main in vivo intracellular pathway elicited by spinal oxytocin during a peripheral inflammatory/persistent nociceptive stimulus. Intrathecal oxytocin reduces early (number of flinches) and late (mechanical allodynia) formalin-induced nociception, an effect abolished by the OTR antagonist (L-368,899). Furthermore, the antinociception observed during the early phase (acute inflammatory) was also reverted by U-73122 (PLC inhibitor) but not by pertussis toxin (Gαi/o protein inhibitor) or gallein (Gβγ subunit inhibitor). In contrast, the late oxytocin-induced behavioral analgesia was blocked by pertussis and gallein but not by U-73122. Since oxytocin's effects during the early phase were also antagonized by Nω-nitro-l-arginine methyl ester, ODQ, or glibenclamide (inhibitors of nitric oxide synthase [NOS], soluble guanylyl cyclase [GC], and K+ATP channels, respectively), the role of two differential pathways elicited by oxytocin is supported. Hence, we showed in in vivo experiments that oxytocin recruits two differential spinal intracellular pathways mediated by Gq (PLC/NOS/GC/K+ATP) or Gi proteins during a peripheral nociceptive stimulus.

Cryo-EM structure of the human MT1-Gi signaling complex.

Melatonin receptors (MT1 and MT2) transduce inhibitory signaling by melatonin (N-acetyl-5-methoxytryptamine), which is associated with sleep induction and circadian rhythm modulation. Although recently reported crystal structures of ligand-bound MT1 and MT2 elucidated the basis of ligand entry and recognition, the ligand-induced MT1 rearrangement leading to Gi-coupling remains unclear. Here we report a cryo-EM structure of the human MT1-Gi signaling complex at 3.3 Å resolution, revealing melatonin-induced conformational changes propagated to the G-protein-coupling interface during activation. In contrast to other Gi-coupled receptors, MT1 exhibits a large outward movement of TM6, which is considered a specific feature of Gs-coupled receptors. Structural comparison of Gi and Gs complexes demonstrated conformational diversity of the C-terminal entry of the Gi protein, suggesting loose and variable interactions at the end of the α5 helix of Gi protein. These notions, together with our biochemical and computational analyses, highlight variable binding modes of Gαi and provide the basis for the selectivity of G-protein signaling.

Analyses of Gnai3-iresGFP reporter mice reveal unknown G\u03b1i3 expression sites

Inhibitory G proteins (Gi proteins) are highly homologous but play distinct biological roles. However, their isoform-specific detection remains challenging. To facilitate the analysis of Gαi3 expression, we generated a Gnai3- iresGFP reporter mouse line. An internal ribosomal entry site (IRES) was inserted behind the stop-codon of the Gnai3 gene to initiate simultaneous translation of the GFP cDNA together with Gαi3. The expression of GFP was confirmed in spleen and thymus tissue by immunoblot analysis. Importantly, the GFP knock-in (ki) did not alter Gαi3 expression levels in all organs tested including spleen and thymus compared to wild-type littermates. Flow cytometry of thymocytes, splenic and blood cell suspensions revealed significantly higher GFP fluorescence intensities in homozygous ki/ki animals compared to heterozygous mice (+/ki). Using cell-type specific surface markers GFP fluorescence was assigned to B cells, T cells, macrophages and granulocytes from both splenic and blood cells and additionally blood-derived platelets. Moreover, immunofluorescent staining of the inner ear from knock-in mice unraveled GFP expression in sensory and non-sensory cell types, with highest levels in Deiter’s cells and in the first row of Hensen’s cells in the organ of Corti, indicating a novel site for Gαi3 expression. In summary, the Gnai3- iresGFP reporter mouse represents an ideal tool for precise analyses of Gαi3 expression patterns and sites.

Human Peptides α-Defensin-1 and -5 Inhibit Pertussis Toxin.

Bordetella pertussis causes the severe childhood disease whooping cough, by releasing several toxins, including pertussis toxin (PT) as a major virulence factor. PT is an AB5-type toxin, and consists of the enzymatic A-subunit PTS1 and five B-subunits, which facilitate binding to cells and transport of PTS1 into the cytosol. PTS1 ADP-ribosylates α-subunits of inhibitory G-proteins (Gαi) in the cytosol, which leads to disturbed cAMP signaling. Since PT is crucial for causing severe courses of disease, our aim is to identify new inhibitors against PT, to provide starting points for novel therapeutic approaches. Here, we investigated the effect of human antimicrobial peptides of the defensin family on PT. We demonstrated that PTS1 enzyme activity in vitro was inhibited by α-defensin-1 and -5, but not β-defensin-1. The amount of ADP-ribosylated Gαi was significantly reduced in PT-treated cells, in the presence of α-defensin-1 and -5. Moreover, both α-defensins decreased PT-mediated effects on cAMP signaling in the living cell-based interference in the Gαi-mediated signal transduction (iGIST) assay. Taken together, we identified the human peptides α-defensin-1 and -5 as inhibitors of PT activity, suggesting that these human peptides bear potential for developing novel therapeutic strategies against whooping cough.

FSH mediated cAMP signalling upregulates the expression of Gα subunits in pubertal rat Sertoli cells

Follicle Stimulating Hormone (FSH) acts via FSH-Receptor (FSH-R) by employing cAMP as the dominant secondary messenger in testicular Sertoli cells (Sc) to support spermatogenesis. Binding of FSH to FSH-R, results the recruitment of the intracellular GTP binding proteins, either stimulatory Gαs or inhibitory Gαi that in turn regulate cAMP production in Sc. The cytosolic concentration of cAMP being generated by FSH-R thereafter critically determines the downstream fate of the FSH signalling. The pleiotropic action of FSH due to differential cAMP output during functional maturation of Sc has been well studied. However, the developmental and cellular regulation of the Gα proteins associated with FSH-R is poorly understood in Sc. In the present study, we report the differential transcriptional modulation of the Gα subunit genes by FSH mediated cAMP signalling in neonatal and pubertal rat Sc. Our data suggested that unlike in neonatal Sc, both the basal and FSH/forskolin induced expression of Gαs, Gαi-1, Gαi-2 and Gαi-3 transcripts was significantly (p < 0.05) up-regulated in pubertal Sc. Further investigations involving treatment of Sc with selective Gαi inhibitor pertussis toxin, confirmed the elevated expression of Gi subunits in pubertal Sc. Collectively our results indicated that the high level of Gαi subunits serves as a negative regulator to optimize cAMP production in pubertal Sc.

Structural basis for the constitutive activity and immunomodulatory properties of the Epstein-Barr virus-encoded G protein-coupled receptor BILF1

Epstein-Barr virus (EBV) encodes a G protein-coupled receptor (GPCR) termed BILF1 that is essential for EBV-mediated immunosuppression and oncogenesis. BILF1 couples with inhibitory G protein (Gi), the major intracellular signaling effector for human chemokine receptors, and exhibits constitutive signaling activity; the ligand(s) for BILF1 are unknown. We studied the origins of BILF1's constitutive activity through structure determination of BILF1 bound to the inhibitory G protein (Gi) heterotrimer. The 3.2-Å resolution cryo-electron microscopy structure revealed an extracellular loop within BILF1 that blocked the typical chemokine binding site, suggesting ligand-autonomous receptor activation. Rather, amino acid substitutions within BILF1 transmembrane regions at hallmark ligand-activated class A GPCR "microswitches" stabilized a constitutively active BILF1 conformation for Gi coupling in a ligand-independent fashion. Thus, the constitutive activity of BILF1 promotes immunosuppression and virulence independent of ligand availability, with implications for the function of GPCRs encoded by related viruses and for therapeutic targeting of EBV.

Role of Membrane Lipid Rafts in MRP4 (ABCC4) Dependent Regulation of the cAMP Pathway in Blood Platelets.

Platelet cytosolic cyclic adenosine monophosphate (cAMP) levels are balanced by synthesis, degradation, and efflux. Efflux can occur via multidrug resistant protein-4 (MRP4; ABCC4) present on dense granule and/or plasma membranes. As lipid rafts have been shown to interfere on cAMP homeostasis, we evaluated the relationships between the distribution and activity of MRP4 in lipid rafts and cAMP efflux. Platelet activation and cAMP homeostasis were analyzed in human and wild-type or MRP4-deleted mouse platelets in the presence of methyl-β-cyclodextrin (MßCD) to disrupt lipid rafts, and of activators of the cAMP signalling pathways. Human platelet MRP4 and effector proteins of the cAMP pathway were analyzed by immunoblots in lipid rafts isolated by differential centrifugation. MßCD dose dependently inhibited human and mouse platelet aggregation without affecting per se cAMP levels. An additive inhibitory effect existed between the adenylate cyclase (AC) activator forskolin and MßCD that was accompanied by an overincrease of cAMP, and which was significantly enhanced upon MRP4 deletion. Finally, an efflux of cAMP out of resting platelets incubated with prostaglandin E1 (PGE1) was observed that was partly dependent on MRP4. Lipid rafts contained a small fraction (≈15%) of MRP4 and most of the inhibitory G-protein Gi, whereas Gs protein, AC3, and phosphodiesterases PDE2 and PDE3A were all present as only trace amounts. Our results are in favour of part of MRP4 present at the platelet surface, including in lipid rafts. Lipid raft integrity is necessary for cAMP signalling regulation, although MRP4 and most players of cAMP homeostasis are essentially located outside rafts.

Structural basis of the activation of the CC chemokine receptor 5 by a chemokine agonist.

The human CC chemokine receptor 5 (CCR5) is a G protein-coupled receptor (GPCR) that plays a major role in inflammation and is involved in cancer, HIV, and COVID-19. Despite its importance as a drug target, the molecular activation mechanism of CCR5, i.e., how chemokine agonists transduce the activation signal through the receptor, is yet unknown. Here, we report the cryo-EM structure of wild-type CCR5 in an active conformation bound to the chemokine super-agonist [6P4]CCL5 and the heterotrimeric Gi protein. The structure provides the rationale for the sequence-activity relation of agonist and antagonist chemokines. The N terminus of agonist chemokines pushes onto specific structural motifs at the bottom of the orthosteric pocket that activate the canonical GPCR microswitch network. This activation mechanism differs substantially from other CC chemokine receptors that bind chemokines with shorter N termini in a shallow binding mode involving unique sequence signatures and a specialized activation mechanism.

Structures of Gi-bound metabotropic glutamate receptors mGlu2 and mGlu4.

The metabotropic glutamate receptors (mGlus) have key roles in modulating cell excitability and synaptic transmission in response to glutamate (the main excitatory neurotransmitter in the central nervous system)1. It has previously been suggested that only one receptor subunit within an mGlu homodimer is responsible for coupling to Gprotein during receptor activation2. However, the molecular mechanism that underlies the asymmetric signalling of mGlus remains unknown. Here we report two cryo-electron microscopy structures of human mGlu2 and mGlu4 bound to heterotrimeric Gi protein. The structures reveal a G-protein-binding site formed by three intracellular loops and helicesIII and IV that is distinct from the corresponding binding site in all ofthe other G-protein-coupled receptor (GPCR) structures. Furthermore, we observed an asymmetric dimer interface of the transmembrane domain of the receptor in the two mGlu-Gi structures. We confirmed that the asymmetric dimerization is crucial for receptor activation, which was supported by functional data; this dimerization may provide a molecular basis for the asymmetric signal transduction of mGlus. These findings offer insights into receptor signalling of classC GPCRs.

OPN5 a new optogenetic receptor to study Gq signalling in the heart with light

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft (DFG) Deutsche Zentrum für Herz-Kreislauf-Forschung (DZHK) Background Gq signalling plays an imperative role in cardiac physiology as well as pathophysiologies such as arrhythmias, hypertrophy, and heart failure. However, the underlying kinetics and the transition from physiological to pathological signalling is yet to be investigated. Optogenetics provides an unprecedented spatial and temporal precision as well as cell specificity, but up to now, selective control of Gq signalling in the intact heart with light has not been achieved. Aim To prove the potential of human Neuropsin (OPN5) to selectively control Gq signalling in the adult heart. Methods The biophysical behaviour of OPN5 in HEK293 cells was characterized by measuring IP1 accumulation, Ca2+ imaging, and patch-clamp analysis of GIRK current activity. We generated a new transgenic mouse model expressing OPN5 in fusion with eYFP under the control of the chicken-β-actin promotor and analysed the expression pattern in the whole heart after tissue clearing with light sheet microscopy and the expression rate after single cell dissociation. Adult isolated cardiomyocytes were examined to measure the effect of OPN5 activation on contractility with a novel custom-made software for on-line contraction analysis by pixel tracking. In Langendorff-perfused hearts, illumination of the sinus node region with UV light (385 nm, 10 s, 1 mW/mm2) was used to measure the influence on the heart rate in electrogram recordings. The light-induced effects and basal ECG parameters as well as the heart-weight-to-femur-length ratio of OPN5 hearts were compared to hearts from non-expressing siblings as well as from CD1 wild-type. Results We prove the selective activation of the Gq proteins by UV light-induced increase in IP3 production and induction of Ca2+ transients in HEK293 cells because both effects were abolished after applying the Gq protein specific blocker FR900359. Promiscuous activation of Gi proteins was excluded by light-induced inhibition of GIRK channels instead of activation. Within two different mouse lines, we found an OPN5/eYFP expression rate of ∼70% within the cardiomyocytes targeted to the plasmamembrane. UV light induced a significant increase in contraction velocity in ventricular cardiomyocytes, and this effect could be abolished by blocking Gq proteins. In the right atrium HCN4 positive sinus nodal cells expressed OPN5/ eYFP and illumination of this region resulted in OPN5 expressing hearts in an average increase of 5.9 ± 0.97% (n= 20, in founder line 1) in the heart rate, which was significant lager than control hearts (all groups &amp;lt;2.4% increase, n≥17). Importantly we could not find any differences in basal ECG parameters or the heart weight-to-femur-length between OPN5 expressing and control. Conclusion We herein prove the specificity of OPN5 for Gq protein activation and demonstrate its use in cardiomyocytes as well as the whole heart. Thus OPN5 is the first optogenetic tool allowing to control Gq signalling in the whole heart precisely.

Healthcare utilization and outcomes in HIV versus non-HIV patients with anal cancer: A nationwide analysis.

e15505 Background: Anal cancer (AC) is the most common HPV-associated cancer in men with HIV. Nearly one third of men with anal cancer have HIV with HPV accounting for 88% of cases. Studies have reported mixed outcomes in HIV-Anal Cancer (HIV-AC) compared to non-HIV-AC patients with most studies being small and retrospective. There were no clear explanations for the differences in the outcomes in both groups. We studied HIV-AC patients from a national database and compared the outcomes and healthcare utilization with non-HIV AC cohort. Methods: We identified all adult patients with AC, with and without HIV, between 2016-2018 from the Healthcare Cost Utilization Project (HCUP) National Inpatient Sample (NIS) database. The groups were compared for socio-demographic differences, inpatient mortality, length of stay (LOS) and total hospital charges (THC). Secondary outcomes studied were rate of acute kidney injury (AKI), tumor lysis syndrome (TLS), lower GI Bleed (LGIB), anemia, tumor lysis (TLS), sepsis, septic shock (SS), neutropenia and protein energy malnutrition (PEM). Statistics was performed using the t-test, univariate and multivariate logistic regression using Stata software. Results: A total of 1235 inpatient admissions with HIV-AC and 10,415 with non-HIV-AC were identified. HIV-AC patients were significantly younger (mean age 50.2 vs 63 years, p &lt; 0.0001) with few over 65 years (8% vs 44.2%, p &lt; 0.0001), more men (82.6% vs 30.8%, p &lt; 0.001), more likely African Americans (AA) (47.8% VS 11.2%, p &lt; 0.0001) and significantly more likely to be treated at a teaching hospital (90.7% vs 9.3%, p &lt; 0.0001) compared to non-HIV-AC cohort. HIV-AC patients had significantly lower odds of inpatient mortality (aOR= 0.26, CI = 0.093 – 0.705, p = 0.008) but higher LOS (7.4 vs 6.5 days, p = 0.02) and higher THC ($74,131 vs $60,864, p = 0.005). Rates of sepsis were higher in HIV-AC (OR = 2.11, CI = 1.465 - 3.028, p &lt; 0.0001) compared to non-HIV-AC, but odds of AKI, TLS, LGIB, SS, anemia, neutropenia and PEM were similar. Conclusions: HIV-AC patients are more likely to be younger, AA, men and have significantly lower inpatient mortality compared to non-HIV-AC, despite higher rates of sepsis. HIV-AC patients being younger and overwhelmingly (90%) treated at teaching hospitals may be contributing to the observed lower mortality. However, the HIV-AC cohort was also a high inpatient healthcare utilizer with significantly increased hospital charges amounting to over $16 million over 3 years. The reversal of sex incidence likely reflects the different exposure to HPV in HIV and non-HIV cohorts. Prospective studies are needed to further evaluate outcomes in HIV-AC patients and identify underlying contributors of higher utilization.

Healthcare utilization and outcomes in HIV versus non-HIV patients with hepatocellular cancer: A nationwide analysis.

e16189 Background: Hepatocellular Carcinoma (HCC) remains a leading cause of cancer related mortality and has a 5-year survival after diagnosis of under 20%. HIV-HCC patients are reported to present with advanced disease and shorter survival compared to non-HIV-HCC patients. HIV has not been known to have a direct causal relationship with HCC but chronic immunosuppression, direct effects of HIV virus on liver parenchyma and use of hepatotoxic antiretroviral medications are thought to contribute to the pathogenesis of HCC (Curr Opin HIV AIDS 2017;12:20-25). We studied differences in outcomes and healthcare utilization between HIV and non-HIV-HCC from a national database. Methods: Healthcare Cost Utilization Project (HCUP) National Inpatient Sample (NIS) database was queried to identify all HIV and non-HIV HCC admissions between 2016-2018. The groups were compared for socio-demographic differences, inpatient mortality, length of stay (LOS) and total hospital charges (THC). Secondary outcomes studied were rates of acute kidney injury (AKI), encephalopathy, anemia, upper GI Bleed (LGIB), tumor lysis (TLS), portal hypertension (PH), sepsis, septic shock (SS), neutropenia and protein energy malnutrition (PEM). Statistics were performed using the t-test, univariate and multivariate logistic regression. Results: A total of 845 HIV-HCC and 88,805 non-HIV-HCC inpatient admissions were identified. Compared to non-HIV-HCC, HIV-HCC patients were significantly younger (mean age 59.3 vs 64.7 years, p &lt; 0.0001) with fewer over 65 years old (21.9 % vs 47.4%, p &lt; 0.0001), more males (87.6% vs 74.3%, p &lt; 0.0002) and African American (AA) (44.8% VS 15.9%, p &lt; 0.0001). HIV-HCC cohort were more likely to be treated at a teaching hospital (89% vs 81%, p &lt; 0.035) and had higher comorbidity burden as defined by a high Charlson comorbidity index (p &lt; 0.01) compared to non-HIV-HCC. Odds of adjusted inpatient mortality (aOR= 0.47, CI = 0.27–0.82, p = 0.007) was significantly lower in HIV-HCC with similar LOS (6.5 vs 6.1 days, p = NS) and THC ($85,930 vs $84,592, p = NS) compared to non-HIV-HCC. While rates of neutropenia (2.96% vs 0.62%, p &lt; 0.001) and PEM (26.0% vs 16.3%, p = 0.01) were higher in HIV-HCC, rates of other secondary outcomes were similar compared to non-HIV cohort. Conclusions: HIV-HCC patients are younger, AA, and men with significantly lower inpatient mortality and similar healthcare utilization compared to non-HIV-HCC, despite higher rates of PEM and neutropenia, possibly reflecting advancements in HIV-HCC treatment, and contributed to by younger age and treatment at teaching hospitals. Further studies are needed to evaluate and assess the effect of co-infection with hepatitis on HIV-HCC outcomes which was not evaluated in present study and investigate interventions aimed to reduce complications like PEM and neutropenia to further improve outcomes.

Особенности влияния бета-адреномиметика гинипрала на радикальную активность нейтрофилов в крови женщин на разных этапах репродукции

In recent years, the idea about the physiological significance of neutrophils, including during pregnancy and childbirth, has evolved significantly. There is an opinion that in the course of pregnancy, the activity of non-specific cellular immunity increases, which, in addition to performing a protective function, forms a mode of contractile activity of the uterus that is optimal for child-bearing. In obstetric practice, in order to reduce uterine hypertonicity in the treatment of miscarriage, β-adrenergic agonists are widely used. However, many aspects of their influence on the mother and the foetus remain insufficiently studied. The aim of this paper was to study the effect of Gynipral (selective β2-adrenergic agonist) on the intensity of latex-induced respiratory burst of venous blood neutrophils in women at different stages of reproduction. Using the chemiluminescence method, we showed for the first time that Gynipral, depending on the stage of reproduction, has multidirectional effect on the latex-induced radical activity of neutrophils in the venous blood of women in vitro. At a low level of radical reaction of neutrophils to latex (in the follicular phase of the cycle, during pregnancy and, which is especially important, during childbirth), Gynipral enhances the oxidative activity of cells; at a high level of radical reaction of neutrophils (during the luteal phase of the cycle and after childbirth), Gynipral inhibits it. It can be assumed that in women, catecholamines (adrenaline) during pregnancy through β2- and/or β3-adrenergic receptors increase the ability of neutrophils to produce activated forms of oxygen, while after delivery they reduce this ability. Such changes in receptor activation may be associated with the phenomenon of switching of β-adrenergic receptor coupling from Gs protein to Gi protein, which is important for regulatory mechanisms. For citation: Polezhaeva T.V., Paturova I.G., Zaytseva O.O., Solomina O.N., Khudyakov A.N., Sergushkina M.I., Dmitrieva S.L., Tsirkin V.I. Effect of Beta-Adrenergic Agonist Gynipral on the Radical Activity of Neutrophils in the Blood of Women at Different Stages of Reproduction. Journal of Medical and Biological Research, 2021, vol. 9, no. 2, pp. 171–181. DOI: 10.37482/2687-1491-Z055