Maternal SARS-CoV-2 infection in pregnancy disrupts gene expression in Hofbauer cells with limited impact on cytotrophoblasts.

BACKGROUND: Hofbauer cells (HBCs) and cytotrophoblasts (CTBs) are major cell populations in placenta. The indirect impact of maternal SARS-CoV-2 disease on these cells that are not directly infected has not been extensively studied. Herein, we profiled gene expression in HBCs and CTBs isolated from placentae of recovered pregnant subjects infected with SARS-CoV-2 during all trimesters of pregnancy, placentae from subjects with active infection, SARS-CoV-2 vaccinated subjects, and those who were unexposed to the virus. METHODS: Placentae were collected within 4 h post-delivery and membrane-free tissues were enzymatically digested for the isolation of HBCs and CTBs. RNA extracted from HBCs and CTBs were sequenced using 150bp paired-end reads. Differentially expressed genes (DEGs) were identified by DESeq2 package in R and enriched in GO Biological Processes, KEGG Pathway, Reactome Gene Sets, Hallmark Gene Sets, and Canonical Pathways. Protein-protein interactions among the DEGs were modelled using STRING and BioGrid. RESULTS: Pregnant subjects (n = 30) were recruited and categorized into six groups: infected with SARS-CoV-2 in i) the first (1T, n = 4), ii) second (2T, n = 5), iii) third (3T, n = 5) trimester, iv) tested positive at delivery (Delivery, n = 5), v) never infected (Control, n = 6), and vi) fully mRNA-vaccinated by delivery (Vaccinated, n = 5). Compared to the Control group, gene expression analysis showed that HBCs from infected subjects had significantly altered gene expression profiles, with the 2T group having the highest number of DEGs (1,696), followed by 3T and 1T groups (1,656 and 958 DEGs, respectively). These DEGs were enriched for pathways involved in immune regulation for host defense, including production of cytokines, chemokines, antimicrobial proteins, ribosomal assembly, neutrophil degranulation inflammation, morphogenesis, and cell migration/adhesion. Protein-protein interaction analysis mapped these DEGs with oxidative phosphorylation, translation, extracellular matrix organization, and type I interferon signaling. Only 95, 23, and 8 DEGs were identified in CTBs of 1T, 2T, and 3T groups, respectively. Similarly, 11 and 3 DEGs were identified in CTBs and HBCs of vaccinated subjects, respectively. Reassuringly, mRNA vaccination did not induce an inflammatory response in placental cells. CONCLUSIONS: Our studies demonstrate a significant impact of indirect SARS-CoV-2 infection on gene expression of inner mesenchymal HBCs, with limited effect on lining CTB cells isolated from pregnant subjects infected and recovered from SARS-CoV-2. The pathways associated with these DEGs identify potential targets for therapeutic intervention.

Vertical Transmission of SARS-CoV-2-Specific Antibodies and Cytokine Profiles in Pregnancy.

Despite intensive characterization of immune responses after COVID-19 infection and vaccination, research examining protective correlates of vertical transmission in pregnancy are limited. Herein, we profiled humoral and cellular characteristics in pregnant women infected or vaccinated at different trimesters and in their corresponding newborns. We noted a significant correlation between spike S1-specific IgG antibody and its RBD-ACE2 blocking activity (receptor-binding domain-human angiotensin-converting enzyme 2) in maternal and cord plasma (P < .001, R > 0.90). Blocking activity of spike S1-specific IgG was significantly higher in pregnant women infected during the third trimester than the first and second trimesters. Elevated levels of 28 cytokines/chemokines, mainly proinflammatory, were noted in maternal plasma with infection at delivery, while cord plasma with maternal infection 2 weeks before delivery exhibited the emergence of anti-inflammatory cytokines. Our data support vertical transmission of protective SARS-CoV-2-specific antibodies. This vertical antibody transmission and the presence of anti-inflammatory cytokines in cord blood may offset adverse outcomes of inflammation in exposed newborns.

The BCL-2 Inhibitor Venetoclax Augments Immune Effector Function Mediated by Fas Ligand, TRAIL, and Perforin/Granzyme B, Resulting in Reduced Plasma Viremia and Decreased HIV Reservoir Size during Acute HIV Infection in a Humanized Mouse Model.

The BCL-2 prosurvival protein is implicated in HIV persistence and is a potential therapeutic target for HIV eradication efforts. We now know that cells harboring HIV are preferentially enriched for high BCL-2 expression, enabling their survival, and that the BCL-2 inhibitor venetoclax promotes the death of actively replicating HIV-infected cells in vitro and ex vivo. Herein, we assess the effect of venetoclax on immune clearance of infected cells and show that BCL-2 inhibition significantly enhances target cell killing induced by Fas ligand, TRAIL (tumor necrosis factor-related apoptosis-inducing ligand), and perforin/granzyme B and synergistically enhances autologous NK (natural killer) and CD8 cells' killing of target cells. In a humanized mouse model of acute HIV infection, venetoclax monotherapy significantly decreases plasma viremia and normalizes CD4:CD8 ratios, and results in more mice with undetectable provirus levels than control. In this model, treatment was associated with leukopenia, as has been described clinically in patients receiving venetoclax for other indications. These data confirm meaningful anti-HIV effects of venetoclax during HIV infection but suggest that venetoclax use should be combined with ART (antiretroviral therapy) to reduce toxicity. IMPORTANCE This study is the first to examine the applicability of BCL-2 inhibition in the setting of active HIV infection in vivo. Furthermore, this study demonstrates that venetoclax significantly enhances target cell killing induced by Fas ligand, TRAIL, and perforin/granzyme B and synergistically enhances autologous NK and CD8 cells' killing of target cells.

Detecting Sources of Immune Activation and Viral Rebound in HIV Infection.

Anti-retroviral therapy (ART) generally suppresses HIV replication to undetectable levels in peripheral blood, but immune activation associated with increased morbidity and mortality is sustained during ART, and infection rebounds when treatment is interrupted. To identify drivers of immune activation and potential sources of viral rebound, we modified RNAscope in situ hybridization to visualize HIV-producing cells as a standard against which to compare the following assays of potential sources of immune activation and virus rebound following treatment interruption: (i) envelope detection by induced transcription-based sequencing (EDITS) assay; (ii) HIV-Flow; (iii) Flow-FISH assays that can scan tissues and cell suspensions to detect rare cells expressing env mRNA, gag mRNA/Gag protein and p24; and (iv) an ultrasensitive immunoassay that detects p24 in cell/tissue lysates at subfemtomolar levels. We show that the sensitivities of these assays are sufficient to detect one rare HIV-producing/env mRNA+/p24+ cell in one million uninfected cells. These high-throughput technologies provide contemporary tools to detect and characterize rare cells producing virus and viral antigens as potential sources of immune activation and viral rebound. IMPORTANCE Anti-retroviral therapy (ART) has greatly improved the quality and length of life for people living with HIV, but immune activation does not normalize during ART, and persistent immune activation has been linked to increased morbidity and mortality. We report a comparison of assays of two potential sources of immune activation during ART: rare cells producing HIV and the virus' major viral protein, p24, benchmarked on a cell model of active and latent infections and a method to visualize HIV-producing cells. We show that assays of HIV envelope mRNA (EDITS assay), gag mRNA, and p24 (Flow-FISH, HIV-Flow. and ultrasensitive p24 immunoassay) detect HIV-producing cells and p24 at sensitivities of one infected cell in a million uninfected cells, thereby providing validated tools to explore sources of immune activation during ART in the lymphoid and other tissue reservoirs.

Optimizing single cell proteomics using trapped ion mobility spectrometry for label-free experiments.

Although single cell RNA-seq has had a tremendous impact on biological research, a corresponding technology for unbiased mass spectrometric analysis of single cells has only recently become available. Significant technological breakthroughs including miniaturized sample handling have enabled proteome profiling of single cells. Furthermore, trapped ion mobility spectrometry (TIMS) in combination with parallel accumulation-serial fragmentation operated in data-dependent acquisition mode (DDA-PASEF) allowed improved proteome coverage from low-input samples. It has been demonstrated that modulating the ion flux in TIMS affects the overall performance of proteome profiling. However, the effect of TIMS settings on the analysis of low-input samples has been less investigated. Thus, we sought to optimize the conditions of TIMS with regard to ion accumulation/ramp times and ion mobility range for low-input samples. We observed that an ion accumulation time of 180 ms and monitoring a narrower ion mobility range from 0.7 to 1.3 V s cm-2 resulted in a substantial gain in the depth of proteome coverage and in detecting proteins with low abundance. We used these optimized conditions for proteome profiling of sorted human primary T cells, which yielded an average of 365, 804, 1116, and 1651 proteins from single, five, ten, and forty T cells, respectively. Notably, we demonstrated that the depth of proteome coverage from a low number of cells was sufficient to delineate several essential metabolic pathways and the T cell receptor signaling pathway. Finally, we showed the feasibility of detecting post-translational modifications including phosphorylation and acetylation from single cells. We believe that such an approach could be applied to label-free analysis of single cells obtained from clinically relevant samples.

The Combination of Venetoclax and Ixazomib Selectively and Efficiently Kills HIV-Infected Cell Lines but Has Unacceptable Toxicity in Primary Cell Models.

The antiapoptotic protein BCL2 inhibits death of HIV-infected cells. Previously, we showed that the BCL2 inhibitor venetoclax selectively kills acutely HIV-infected cells and reduces HIV DNA in latently infected CD4 T cells ex vivo after reactivation with anti-CD3/anti-CD28. However, there is a need to identify a combination therapy with venetoclax and a clinically relevant latency reversal agent. Ixazomib is an oral proteasome inhibitor which we have shown reactivates latent HIV and predisposes reactivated cells to cell death. Here, we determined that the combination of venetoclax and ixazomib kills more latently HIV-infected cells and leads to greater reduction in HIV replication than either treatment alone in vitro in a T cell model. However, combination treatment of ex vivo CD4 T cells from antiretroviral therapy (ART)-suppressed, HIV-positive participants resulted in unanticipated and unacceptable nonspecific toxicity in primary cells. Therefore, while we show proof of concept that multiple agents can enhance selective killing of HIV-infected cells, the combination of venetoclax and ixazomib has unacceptable toxicity in primary cells, and so further investigation is needed to identify a clinically relevant latency reversal agent to combine with venetoclax as a novel strategy to reduce the size of the HIV reservoir.IMPORTANCE A cure for HIV would require eliminating cells that contain the virus in a latent form from the body. Current antiretroviral medications are unable to rid the body of latently infected cells. Here, we show that a combination of investigational agents-ixazomib plus venetoclax-which reactivate latent virus and predispose infected cells to apoptosis may reduce latent virus in a T cell model, but at the expense of nonspecific toxicity in primary cells.

Reactivating latent HIV with PKC agonists induces resistance to apoptosis and is associated with phosphorylation and activation of BCL2.

Eradication of HIV-1 by the "kick and kill" strategy requires reactivation of latent virus to cause death of infected cells by either HIV-induced or immune-mediated apoptosis. To date this strategy has been unsuccessful, possibly due to insufficient cell death in reactivated cells to effectively reduce HIV-1 reservoir size. As a possible cause for this cell death resistance, we examined whether leading latency reversal agents (LRAs) affected apoptosis sensitivity of CD4 T cells. Multiple LRAs of different classes inhibited apoptosis in CD4 T cells. Protein kinase C (PKC) agonists bryostatin-1 and prostratin induced phosphorylation and enhanced neutralizing capability of the anti-apoptotic protein BCL2 in a PKC-dependent manner, leading to resistance to apoptosis induced by both intrinsic and extrinsic death stimuli. Furthermore, HIV-1 producing CD4 T cells expressed more BCL2 than uninfected cells, both in vivo and after ex vivo reactivation. Therefore, activation of BCL2 likely contributes to HIV-1 persistence after latency reversal with PKC agonists. The effects of LRAs on apoptosis sensitivity should be considered in designing HIV cure strategies predicated upon the "kick and kill" paradigm.

Mass Spectrometric Analysis of Urine from COVID-19 Patients for Detection of SARS-CoV-2 Viral Antigen and to Study Host Response.

SARS-CoV-2 infection has become a major public health burden and affects many organs including lungs, kidneys, the liver, and the brain. Although the virus is readily detected and diagnosed using nasopharyngeal swabs by reverse transcriptase polymerase chain reaction (RT-PCR), detection of its presence in body fluids is fraught with difficulties. A number of published studies have failed to detect viral RNA by RT-PCR methods in urine. Although microbial identification in clinical microbiology using mass spectrometry is undertaken after culture, here we undertook a mass spectrometry-based approach that employed an enrichment step to capture and detect SARS-CoV-2 nucleocapsid protein directly from urine of COVID-19 patients without any culture. We detected SARS-CoV-2 nucleocapsid protein-derived peptides from 13 out of 39 urine samples. Further, a subset of COVID-19 positive and COVID-19 negative urine samples validated by mass spectrometry were used for the quantitative proteomics analysis. Proteins with increased abundance in urine of SARS-CoV-2 positive individuals were enriched in the acute phase response, regulation of complement system, and immune response. Notably, a number of renal proteins such as podocin (NPHS2), an amino acid transporter (SLC36A2), and sodium/glucose cotransporter 5 (SLC5A10), which are intimately involved in normal kidney function, were decreased in the urine of COVID-19 patients. Overall, the detection of viral antigens in urine using mass spectrometry and alterations of the urinary proteome could provide insights into understanding the pathogenesis of COVID-19.

Liver transplantation for acute liver failure in a SARS-CoV-2 PCR-positive patient.

Current guidelines recommend deferring liver transplantation (LT) in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection until clinical improvement occurs and two PCR tests collected at least 24 hours apart are negative. We report a case of an 18-year-old, previously healthy African-American woman diagnosed with COVID-19, who presents with acute liver failure (ALF) requiring urgent LT in the context of SARS-CoV-2 polymerase chain reaction (PCR) positivity. The patient was thought to have acute Wilsonian crisis on the basis of hemolytic anemia, alkaline phosphatase:bilirubin ratio <4, AST:ALT ratio >2.2, elevated serum copper, and low uric acid, although an unusual presentation of COVID-19 causing ALF could not be excluded. After meeting criteria for status 1a listing, the patient underwent successful LT, despite ongoing SARS-CoV-2 PCR positivity. Remdesivir was given immediately posttransplant, and mycophenolate mofetil was withheld initially and the SARS-CoV-2 PCR test eventually became negative. Three months following transplantation, the patient has made a near-complete recovery. This case highlights that COVID-19 with SARS-CoV-2 PCR positivity may not be an absolute contraindication for transplantation in ALF. Criteria for patient selection and timing of LT amid the COVID-19 pandemic need to be validated in future studies.

Healthcare disparities among anticoagulation therapies for severe COVID-19 patients in the multi-site VIRUS registry.

Here we analyze hospitalized andintensive care unit coronavirus disease 2019 (COVID-19) patient outcomes from the international VIRUS registry (https://clinicaltrials.gov/ct2/show/NCT04323787). We find that COVID-19 patients administered unfractionated heparin but not enoxaparin have a higher mortality-rate (390 of 1012 = 39%) compared to patients administered enoxaparin but not unfractionated heparin (270 of 1939 = 14%), presenting a risk ratio of 2.79 (95% confidence interval [CI]: [2.42, 3.16]; p = 4.45e-52). This difference persists even after balancing on a number of covariates including demographics, comorbidities, admission diagnoses, and method of oxygenation, with an increased mortality rate on discharge from the hospital of 37% (268 of 733) for unfractionated heparin versus 22% (154 of 711) for enoxaparin, presenting a risk ratio of 1.69 (95% CI: [1.42, 2.00]; p = 1.5e-8). In these balanced cohorts, a number of complications occurred at an elevated rate for patients administered unfractionated heparin compared to patients administered enoxaparin, including acute kidney injury, acute cardiac injury, septic shock, and anemia. Furthermore, a higher percentage of Black/African American COVID patients (414 of 1294 [32%]) were noted to receive unfractionated heparin compared to White/Caucasian COVID patients (671 of 2644 [25%]), risk ratio 1.26 (95% CI: [1.14, 1.40]; p = 7.5e-5). After balancing upon available clinical covariates, this difference in anticoagulant use remained statistically significant (311 of 1047 [30%] for Black/African American vs. 263 of 1047 [25%] for White/Caucasian, p = .02, risk ratio 1.18; 95% CI: [1.03, 1.36]). While retrospective studies cannot suggest any causality, these findings motivate the need for follow-up prospective research into the observed racial disparity in anticoagulant use and outcomes for severe COVID-19 patients.

Safety and efficacy of (+)-epicatechin in subjects with Friedreich's ataxia: A phase II, open-label, prospective study.

BACKGROUND: (+)-Epicatechin (EPI) induces mitochondrial biogenesis and antioxidant metabolism in muscle fibers and neurons. We aimed to evaluate safety and efficacy of (+)-EPI in pediatric subjects with Friedreich's ataxia (FRDA). METHODS: This was a phase II, open-label, baseline-controlled single-center trial including 10 participants ages 10 to 22 with confirmed FA diagnosis. (+)-EPI was administered orally at 75 mg/d for 24 weeks, with escalation to 150 mg/d at 12 weeks for subjects not showing improvement of neuromuscular, neurological or cardiac endpoints. Neurological endpoints were change from baseline in Friedreich's Ataxia Rating Scale (FARS) and 8-m timed walk. Cardiac endpoints were changes from baseline in left ventricular (LV) structure and function by cardiac magnetic resonance imaging (MRI) and echocardiogram, changes in cardiac electrophysiology, and changes in biomarkers for heart failure and hypertrophy. RESULTS: Mean FARS/modified (m)FARS scores showed nonstatistically significant improvement by both group and individual analysis. FARS/mFARS scores improved in 5/9 subjects (56%), 8-m walk in 3/9 (33%), 9-peg hole test in 6/10 (60%). LV mass index by cardiac MRI was significantly reduced at 12 weeks (P = .045), and was improved in 7/10 (70%) subjects at 24 weeks. Mean LV ejection fraction was increased at 24 weeks (P = .008) compared to baseline. Mean maximal septal thickness by echocardiography was increased at 24 weeks (P = .031). There were no serious adverse events. CONCLUSION: (+)-EPI was well tolerated over 24 weeks at up to 150 mg/d. Improvement was observed in cardiac structure and function in subset of subjects with FRDA without statistically significant improvement in primary neurological outcomes. SYNOPSIS: A (+)-epicatechin showed improvement of cardiac function, nonsignificant reduction of FARS/mFARS scores, and sustained significant upregulation of muscle-regeneration biomarker follistatin.

TRAILshort Protects against CD4 T Cell Death during Acute HIV Infection.

CD4 T cells from HIV-1 infected patients die at excessive rates compared to those from uninfected patients, causing immunodeficiency. We previously identified a dominant negative ligand that antagonizes the TRAIL-dependent pathway of cell death, which we called TRAILshort. Because the TRAIL pathway has been implicated in CD4 T cell death occurring during HIV-1 infection, we used short hairpin RNA knockdown, CRISPR deletion, or Abs specific for TRAILshort to determine the effect of inhibiting TRAILshort on the outcome of experimental acute HIV infection in vitro. Strikingly, all three approaches to TRAILshort deletion/inhibition enhanced HIV-induced death of both infected and uninfected human CD4 T cells. Thus, TRAILshort impacts T cell dynamics during HIV infection, and inhibiting TRAILshort causes more HIV-infected and uninfected bystander cells to die. TRAILshort is, therefore, a host-derived, host-adaptive mechanism to limit the effects of TRAIL-induced cell death. Further studies on the effects of TRAILshort in other disease states are warranted.

Statins as an adjunctive therapy for COVID-19: the biological and clinical plausibility.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes the coronavirus disease 2019 (COVID-19) has infected millions of individuals and has claimed hundreds of thousands of human lives worldwide. Patients with underlying cardiovascular conditions are at high risk for SARS-CoV-2 infection, and COVID-19 patients have high incidence of cardiovascular complications such as acute cardiac injury, arrhythmias, heart failure, and thromboembolism. The disease has no approved proven effective therapy and hence repurposing of existing approved drugs has been considered as the fastest treatment approach. Statins have been shown to exhibit lipid lowering dependent and independent cardiovascular protective effects as well as favorable effects in various other pathophysiological states. These beneficial properties of statins are a result of their multiple pleotropic effects that include, anti-inflammatory, immunomodulatory, antithrombotic and antimicrobial properties. In this review, we provide a comprehensive description of the mechanisms of the pleotropic effects of statins, the relevant pre-clinical and clinical data pertinent to their role in infections and acute lung injury, the possible cardiovascular benefits of statins in COVID-19, and the implications of the therapeutic potential of statins in COVID-19 disease. We conclude with the rationale for conducting randomized controlled trials of statins in COVID-19 disease.

Cerebral Venous Sinus Thrombosis is not Significantly Linked to COVID-19 Vaccines or Non-COVID Vaccines in a Large Multi-State Health System.

OBJECTIVE: To assess the association of COVID-19 vaccines and non-COVID-19 vaccines with cerebral venous sinus thrombosis (CVST). MATERIALS AND METHOD: We retrospectively analyzed a cohort of 771,805 vaccination events across 266,094 patients in the Mayo Clinic Health System between 01/01/2017 and 03/15/2021. The primary outcome was a positive diagnosis of CVST, identified either by the presence of a corresponding ICD code or by an NLP algorithm which detected positive diagnosis of CVST within free-text clinical notes. For each vaccine we calculated the relative risk by dividing the incidence of CVST in the 30 days following vaccination to that in the 30 days preceding vaccination. RESULTS: We identified vaccination events for all FDA-approved COVID-19 vaccines including Pfizer-BioNTech (n = 94,818 doses), Moderna (n = 36,350 doses) and Johnson & Johnson - J&J (n = 1,745 doses). We also identified vaccinations events for 10 common FDA-approved non-COVID-19 vaccines (n = 771,805 doses). There was no statistically significant difference in the incidence rate of CVST in 30-days before and after vaccination for any vaccine in this population. We further found the baseline CVST incidence in the study population between 2017 and 2021 to be 45 to 98 per million patient years. CONCLUSIONS: This real-world evidence-based study finds that CVST is rare and is not significantly associated with COVID-19 vaccination in our patient cohort. Limitations include the rarity of CVST in our dataset, a relatively small number of J&J COVID-19 vaccination events, and the use of a population drawn from recipients of a SARS-CoV-2 PCR test in a single health system.

The Role of the BCL-2 Family of Proteins in HIV-1 Pathogenesis and Persistence.

Advances in HIV-1 therapy have transformed the once fatal infection into a manageable, chronic condition, yet the search for a widely applicable approach to cure remains elusive. The ineffectiveness of antiretroviral therapy (ART) in reducing the size of the HIV-1 latent reservoir has prompted investigation into the mechanisms of HIV-1 latency and immune escape. One of the major regulators of apoptosis, the BCL-2 protein, alongside its homologous family members, is a major target of HIV-1-induced change. Recent studies have now demonstrated the association of this protein with cells that support proviral forms in the setting of latency and have helped identify BCL-2 as a novel and promising therapeutic target for HIV-1 therapy directed at possible cure. This review aims to systematically review the interactions of HIV-1 with BCL-2 and its homologs and to examine the possibility of using BCL-2 inhibitors in the study and elimination of the latent reservoir.

Both HIV-Infected and Uninfected Cells Express TRAILshort, Which Confers TRAIL Resistance upon Bystander Cells within the Microenvironment.

TNF-related apoptosis-inducing ligand (TRAIL) was initially described to induce apoptosis of tumor cells and/or virally infected cells, although sparing normal cells, and has been implicated in the pathogenesis of HIV disease. We previously identified TRAILshort, a TRAIL splice variant, in HIV-infected patients and characterized it as being a dominant negative ligand to subvert TRAIL-mediated killing. Herein, using single-cell genomics we demonstrate that TRAILshort is produced by HIV-infected cells, as well as by uninfected bystander cells, and that the dominant stimulus which induces TRAILshort production are type I IFNs and TLR7, TLR8, and TLR9 agonists. TRAILshort has a short t1/2 by virtue of containing a PEST domain, which targets the protein toward the ubiquitin proteasome pathway for degradation. Further we show that TRAILshort binds preferentially to TRAIL receptors 1 and 2 with significantly reduced interaction with the decoy TRAIL receptors 3 and 4. Recombinant TRAILshort is sufficient to protect cells against TRAIL-induced killing, whereas immunodepletion of TRAILshort with a specific Ab restores TRAIL sensitivity. Importantly we show that TRAILshort is shed in microvesicles into the cellular microenvironment and therefore confers TRAIL resistance not only on the cell which produces it, but also upon neighboring bystander cells. These results establish a novel paradigm for understanding and overcoming TRAIL resistance, in particular how HIV-infected cells escape immune elimination by the TRAIL:TRAILshort receptor axis.

Risks and Outcomes of Allogeneic Hematopoietic Stem Cell Transplantation for Hematologic Malignancies in Patients with HIV Infection.

Allogeneic hematopoietic cell transplantation (allo-HCT) is a potentially curative therapy for hematologic malignancies in persons living with HIV (PLHIV), however, uncertainties exist in many domains related to their care, including optimal donor selection, conditioning regimen, immunosuppression for graft-versus-host disease (GVHD), and long-term outcomes. We undertook a comprehensive systematic review from multiple databases to evaluate the foregoing uncertainties. The final sample comprised 49 patients (median age at HCT, 34 years; 46 males [93.8%]). Acute GVHD (aGVHD) was reported in 19 patients (59.3%) in the overall cohort, with grade II in 12 (37.5%) and grade III in 2 (6.2%). In the entire cohort, overall survival (OS) was 81.6% at 6 months and 56.6% at 12 months. Among 32 patients, the OS at 6 months was 73.3% for patients who received myeloablative conditioning (MAC) and 88.2% for those who received reduced-intensity conditioning (RIC), and OS at 12 months was 53.3% for MAC and 58.8% for RIC. Twenty-four patients were alive in complete remission on long-term follow-up, with 25 deaths reported. Fifteen deaths (60%) occurred due to relapse, including 3 (12%) from infection, 2 (8%) from GVHD, and 5 (20%) from other causes, including renal failure, respiratory failure, and liver failure. To our knowledge, this is the largest series of allo-HCT in PLHIV reported to date, and our results indicate that clinical outcomes (including engraftment, infection rate, and survival) are not significantly different from those in patients without HIV (historical controls). RIC regimens are associated with a slightly greater likelihood of survival compared with MAC regimens. Prospective trials are critically needed to evaluate the optimal conditioning regimens, ideal donor source, and most appropriate GVHD prophylaxis.

HIV Protease-Generated Casp8p41, When Bound and Inactivated by Bcl2, Is Degraded by the Proteasome.

HIV protease is known to cause cell death, which is dependent upon cleavage of procaspase 8. HIV protease cleavage of procaspase 8 generates Casp8p41, which directly binds Bak with nanomolar affinity, causing Bak activation and consequent cell death. Casp8p41 can also bind Bcl2 with nanomolar affinity, in which case cell death is averted. Central memory CD4 T cells express high levels of Bcl2, possibly explaining why those cells do not die when they reactivate HIV. Here, we determine that the Casp8p41-Bcl2 complex is polyubiquitinated and degraded by the proteasome. Ixazomib, a proteasome inhibitor in clinical use, blocks this pathway, increasing the abundance of Casp8p41 and causing more cells to die in a Casp8p41-dependent manner.IMPORTANCE The Casp8p41 pathway of cell death is unique to HIV-infected cells yet is blocked by Bcl2. Once bound by Bcl2, Casp8p41 is polyubiquitinated and degraded by the proteasome. Proteasome inhibition blocks degradation of Casp8p41, increasing Casp8p41 levels and causing more HIV-infected cells to die.

The TRAIL: TRAILshort Axis in HIV Immunopathology.

Accelerated loss of HIV-infected and uninfected CD4 T cells is a hallmark of HIV infection that leads to severe immunodeficiency, rendering the host susceptible to opportunistic infections and malignancies. Obstacles to eradicating HIV involve the virus's ability to remain in a quiescent state as latent viral reservoirs and manipulate host defenses to benefit viral survival and persistence of the infected reservoir. Several mechanisms cause CD4 T-cell depletion and recent studies demonstrate the role of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in this process. Expression of TRAIL and its receptors is upregulated in response to HIV infection. TRAIL interacts with its receptors to activate apoptotic pathways. We recently demonstrated the presence of TRAILshort, a novel splice variant of full-length TRAIL, in the serum of HIV-infected patients. A unique carboxy-terminus allows TRAILshort to bind to death receptors without inducing apoptosis and prevents TRAIL from binding to its receptors, thereby conferring resistance to TRAIL-mediated death. In this review, we describe how the TRAIL: TRAILshort receptor axis modulates apoptosis of different types of immune cells in the context of HIV infection. We also discuss how TRAIL and TRAILshort contribute to the activation of immune cells involved in host defense against HIV and mechanisms that HIV has evolved to manipulate TRAIL for its survival.