Expression of HIV-1 matrix protein p17 and association with B-cell lymphoma in HIV-1 transgenic mice

12-week Dolutegravir treatment marginally reduces energy expenditure but does not increase body weight or alter vascular function in a murine model of Human Immunodeficiency Virus infection

Combination antiretroviral therapy (cART) has markedly increased life expectancy in people with HIV (PWH) but has also resulted in an increased prevalence of cardiometabolic disorders, whose etiopathology remains ill-defined. Notably, the respective contribution of cART and HIV-derived proteins to obesity and vascular alterations remain poorly understood. Therefore, we investigated the individual and combined effects of HIV-proteins and of the integrase strand transfer inhibitor Dolutegravir (DTG) on body composition and vascular reactivity. Male wildtype (WT) and HIV transgenic (Tg26) mice, received DTG or vehicle for 12 weeks. Viral proteins expression in Tg26 mice lowered fat mass, increased heat production, and induced a 2-fold increase in brown adipose tissue (BAT) uncoupling protein 1 (UCP1) expression. DTG increased the expression of markers of adipogenesis in adipocytes in culture, but also reduced heat production and BAT UCP1 and UCP3 expression in Tg26 mice. DTG increased food intake, fat percentage and protected from lean mass reduction in Tg26 mice only. However, DTG did not increase body weight in either WT or Tg26 mice. Viral protein expression reduced acetylcholine (endothelium)-mediated relaxation by 14% in mesenteric arteries preconstricted with phenylephrine. However, DTG did not impair nor improve endothelium-dependent relaxation. Together, these data indicate that DTG's effects on food intake, adipogenesis and energy expenditure are insufficient to increase body weight, even in the presence of HIV-proteins, suggesting that body weight gain in PWH involves additional factors likely including other cART components and pre-existing comorbidities. Moreover, these data rule out DTG as a source of vascular disorders in PWH.

Identification of viral protein R of human immunodeficiency virus-1 (HIV) and interleukin-6 as risk factors for malignancies in HIV-infected individuals: A cohort study

BACKGROUND

Despite effective antiretroviral therapy, patients with human immunodeficiency virus type-1 (HIV) suffer from a high frequency of malignancies, but related risk factors remain elusive. Here, we focused on blood-circulating viral protein R (Vpr) of HIV, which induces proinflammatory cytokine production and genotoxicity by exogenous functions.

METHODS AND FINDINGS

A total 404 blood samples of HIV patients comprising of 126 patients with malignancies (tumor group) and 278 patients without malignancies (non-tumor group), each of 96 samples was first selected by one-to-one propensity score matching. By a detergent-free enzyme-linked immunosorbent assays (detection limit, 3.9 ng/mL), we detected Vpr at a higher frequency in the matched tumor group (56.3%) than in the matched non-tumor group (39.6%) (P = 0.030), although there was no different distribution of Vpr levels (P = 0.372). We also detected anti-Vpr immunoglobulin (IgG), less frequently in the tumor group compared with the tumor group (22.9% for tumor group vs. 44.8% for non-tumor group, P = 0.002), and the proportion of patients positive for Vpr but negative of anti-Vpr IgG was significantly higher in the tumor group than in the non-tumor group (38.6% vs. 15.6%, respectively, P < 0.001). Additionally, Interleukin-6 (IL-6), the levels of which were high in HIV-1 infected patients (P < 0.001) compared to non-HIV-infected individuals, was significantly higher in advanced cases of tumors (P < 0.001), and IL-6 level was correlated with Vpr in the non-tumor group (P = 0.010). Finally, multivariate logistic regression analysis suggested a positive link of Vpr with tumor occurrence in HIV patients (P = 0.002).

CONCLUSION

Vpr and IL-6 could be risk factors of HIV-1 associated malignancies, and it would be importance to monitor these molecules for well managing people living with HIV-1.

Correlation of HIV-Induced Neuroinflammation and Synaptopathy with Impairment of Learning and Memory in Mice with HAND

Over 38 million people worldwide are living with HIV/AIDS, and more than half of them are affected by HIV-associated neurocognitive disorders (HAND). Such disorders are characterized by chronic neuroinflammation, neurotoxicity, and central nervous system deterioration, which lead to short- or long-term memory loss, cognitive impairment, and motor skill deficits that may show gender disparities. However, the underlying mechanisms remain unclear. Our previous study suggested that HIV-1 infection and viral protein R (Vpr) upregulate the SUR1-TRPM4 channel associated with neuroinflammation, which may contribute to HAND. The present study aimed to explore this relationship in a mouse model of HAND. This study employed the HIV transgenic Tg26 mouse model, comparing Tg26 mice with wildtype mice in various cognitive behavioral and memory tests, including locomotor activity tests, recognition memory tests, and spatial learning and memory tests. The study found that Tg26 mice exhibited impaired cognitive skills and reduced learning abilities compared to wildtype mice, particularly in spatial memory. Interestingly, male Tg26 mice displayed significant differences in spatial memory losses (p < 0.001), while no significant differences were identified in female mice. Consistent with our early results, SUR1-TRPM4 channels were upregulated in Tg26 mice along with glial fibrillary acidic protein (GFAP) and aquaporin 4 (AQP4), consistent with reactive astrocytosis and neuroinflammation. Corresponding reductions in neurosynaptic responses, as indicated by downregulation of Synapsin-1 (SYN1) and Synaptophysin (SYP), suggested synaptopathy as a possible mechanism underlying cognitive and motor skill deficits. In conclusion, our study suggests a possible relationship between SUR1-TRPM4-mediated neuroinflammation and synaptopathy with impairments of learning and memory in mice with HAND. These findings could help to develop new therapeutic strategies for individuals living with HAND.

High expression of HIV-1 matrix protein p17 in both lymphoma and lymph node tissues of AIDS patients

BACKGROUND

HIV-1 matrix protein p17 was found to be associated with lymphoma development in vitro. This study aimed to elucidate the pathogenetic roles of HIV-1 p17 in AIDS-related lymphoma.

METHODS

Expression of HIV-1 proteins p17, p24, nef and tat were evaluated in tumor tissue samples from 60 lymphoma patients and lymph node samples from 23 non-lymphoma patients with HIV-1 infection by immunohistochemistry. Microvascular density (MVD) determined by CD34 were also assessed in tumor tissues. Clinicopathological data of AIDS patients with lymphoma were collected retrospectively.

RESULTS

The subtypes of lymphoma among sixty AIDS patients were diffuse large B-cell lymphoma (32 cases), Burkitt lymphoma (23 cases), Hodgkin's lymphoma (4 cases), and plasmablastic lymphoma (1 case). The expression rate of HIV-1 p17 in lymphoma and non-lymphoma group was 63 % (38/60) and 61 % (14/29) respectively, with no significant difference (p = 0.835). The positive expression rate of p17 in both groups was significantly higher than that of p24, nef and tat (p < 0.05). The expression of p17 was associated with a higher MVD in the lymphoma group (p < 0.05). There were no significant differences in the 2-years overall survival between p17 positive and negative group (61 % vs. 50 %, p = 0.525).

CONCLUSION

The common expression of HIV-1 matrix protein p17 in both lymphoma and lymph node tissues of AIDS patients and the association between p17 expression and the higher MVD suggest that the accumulation and persistence of p17 in tissues may play a role in lymphoma development.

GWAS in Mice Maps Susceptibility to HIV-Associated Nephropathy to the Ssbp2 Locus

BACKGROUND

To gain insight into the pathogenesis of collapsing glomerulopathy, a rare form of FSGS that often arises in the setting of viral infections, we performed a genome-wide association study (GWAS) among inbred mouse strains using a murine model of HIV-1 associated nephropathy (HIVAN).

METHODS

We first generated F1 hybrids between HIV-1 transgenic mice on the FVB/NJ background and 20 inbred laboratory strains. Analysis of histology, BUN, and urinary NGAL demonstrated marked phenotypic variation among the transgenic F1 hybrids, providing strong evidence for host genetic factors in the predisposition to nephropathy. A GWAS in 365 transgenic F1 hybrids generated from these 20 inbred strains was performed.

RESULTS

We identified a genome-wide significant locus on chromosome 13-C3 and multiple additional suggestive loci. Crossannotation of the Chr. 13 locus, including single-cell transcriptomic analysis of wildtype and HIV-1 transgenic mouse kidneys, nominated Ssbp2 as the most likely candidate gene. Ssbp2 is highly expressed in podocytes, encodes a transcriptional cofactor that interacts with LDB1 and LMX1B, which are both previously implicated in FSGS. Consistent with these data, older Ssbp2 null mice spontaneously develop glomerulosclerosis, tubular casts, interstitial fibrosis, and inflammation, similar to the HIVAN mouse model.

CONCLUSIONS

These findings demonstrate the utility of GWAS in mice to uncover host genetic factors for rare kidney traits and suggest Ssbp2 as susceptibility gene for HIVAN, potentially acting via the LDB1-LMX1B transcriptional network.

7,8-Dihydroxyflavone improves neuropathological changes in the brain of Tg26 mice, a model for HIV-associated neurocognitive disorder

The combined antiretroviral therapy era has significantly increased the lifespan of people with HIV (PWH), turning a fatal disease to a chronic one. However, this lower but persistent level of HIV infection increases the susceptibility of HIV-associated neurocognitive disorder (HAND). Therefore, research is currently seeking improved treatment for this complication of HIV. In PWH, low levels of brain derived neurotrophic factor (BDNF) has been associated with worse neurocognitive impairment. Hence, BDNF administration has been gaining relevance as a possible adjunct therapy for HAND. However, systemic administration of BDNF is impractical because of poor pharmacological profile. Therefore, we investigated the neuroprotective effects of BDNF-mimicking 7,8 dihydroxyflavone (DHF), a bioactive high-affinity TrkB agonist, in the memory-involved hippocampus and brain cortex of Tg26 mice, a murine model for HAND. In these brain regions, we observed astrogliosis, increased expression of chemokine HIV-1 coreceptors CXCR4 and CCR5, neuroinflammation, and mitochondrial damage. Hippocampi and cortices of DHF treated mice exhibited a reversal of these pathological changes, suggesting the therapeutic potential of DHF in HAND. Moreover, our data indicates that DHF increases the phosphorylation of TrkB, providing new insights about the role of the TrkB-Akt-NFkB signaling pathway in mediating these pathological hallmarks. These findings guide future research as DHF shows promise as a TrkB agonist treatment for HAND patients in adjunction to the current antiviral therapies.

HIV-1 Transactivator of Transcription (Tat) Co-operates With AP-1 Factors to Enhance c-MYC Transcription

HIV-1 infection often leads to the development of co-morbidities including cancer. Burkitt lymphoma (BL) is one of the most over-represented non-Hodgkin lymphoma among HIV-infected individuals, and displays a highly aggressive phenotype in this population group, with comparatively poorer outcomes, despite these patients being on anti-retroviral therapy. Accumulating evidence indicates that the molecular pathogenesis of HIV-associated malignancies is unique, with components of the virus playing an active role in driving oncogenesis, and in order to improve patient prognosis and treatment, a better understanding of disease pathobiology and progression is needed. In this study, we found HIV-1 Tat to be localized within the tumor cells of BL patients, and enhanced expression of oncogenic c-MYC in these cells. Using luciferase reporter assays we show that HIV-1 Tat enhances the c-MYC gene promoter activity and that this is partially mediated via two AP-1 binding elements located at positions -1128 and -1375 bp, as revealed by mutagenesis experiments. We further demonstrate, using pull-down assays, that Tat can exist within a protein complex with the AP-1 factor JunB, and that this complex can bind these AP-1 sites within the c-MYC promoter, as shown by in vivo chromatin immunoprecipitation assays. Therefore, these findings show that in HIV-infected individuals, Tat infiltrates B-cells, where it can enhance the expression of oncogenic factors, which contributes toward the more aggressive disease phenotype observed in these patients.

HIV p17 enhances T cell proliferation by suppressing autophagy through the p17-OLA1-GSK3β axis under nutrient starvation

Nutrient starvation is a common phenomenon that occurs during T cell activation. Upon pathogen infection, large amounts of immune cells migrate to infection sites, and antigen-specific T cells are activated; this is followed by rapid proliferation through clonal expansion. The dramatic expansion of cells will commonly lead to nutrient shortage. Cellular autophagy is often upregulated as a way to sustain the body's energy requirements. During infection, human immunodeficiency virus (HIV) co-opts a series of host cell metabolic pathways for replication. Several HIV proteins, such as Env, Nef, and Vpr, have already been reported as being involved in autophagy-related processes. In this report, we identified that the HIV p17 protein acts as a major factor in suppressing the autophagic process in T cells, especially under glucose starvation condition. HIV p17 interacts with Obg-like ATPase 1 (OLA1) and disrupts OLA1-glycogen synthase kinase-3 beta (GSK3β) complex, leading to GSK3β hyperactivation. Consequently, a prior proliferation of HIV-infected T cells under glucose starvation will occur. The inhibition of autophagy also aids HIV replication by antagonizing the antiviral effect of autophagy. Our study shows a new cellular pathway that HIV can hijack for viral spreading by a prior proliferation of HIV-loaded T cells and may provide new therapeutic targets for acquired immunodeficiency syndrome intervention.

Oncogenic Effects of HIV-1 Proteins, Mechanisms Behind

People living with human immunodeficiency virus (HIV-1) are at increased risk of developing cancer, such as Kaposi sarcoma (KS), non-Hodgkin lymphoma (NHL), cervical cancer, and other cancers associated with chronic viral infections. Traditionally, this is linked to HIV-1-induced immune suppression with depletion of CD4+ T-helper cells, exhaustion of lymphopoiesis and lymphocyte dysfunction. However, the long-term successful implementation of antiretroviral therapy (ART) with an early start did not preclude the oncological complications, implying that HIV-1 and its antigens are directly involved in carcinogenesis and may exert their effects on the background of restored immune system even when present at extremely low levels. Experimental data indicate that HIV-1 virions and single viral antigens can enter a wide variety of cells, including epithelial. This review is focused on the effects of five viral proteins: envelope protein gp120, accessory protein negative factor Nef, matrix protein p17, transactivator of transcription Tat and reverse transcriptase RT. Gp120, Nef, p17, Tat, and RT cause oxidative stress, can be released from HIV-1-infected cells and are oncogenic. All five are in a position to affect "innocent" bystander cells, specifically, to cause the propagation of (pre)existing malignant and malignant transformation of normal epithelial cells, giving grounds to the direct carcinogenic effects of HIV-1.

A longitudinal characterization of sex-specific somatosensory and spatial memory deficits in HIV Tg26 heterozygous mice

The pathogenesis of human immunodeficiency virus associated neurological disorders is still not well understood, yet is known to result in neurological declines despite combination anti-retroviral therapy. HIV-1 transgenic (Tg26) mice contain integrated non-infectious HIV-1 proviral DNA. We sought to assess the integrity of neurocognitive function and sensory systems in HIV-1 Tg26 mice using a longitudinal design, in both sexes, to examine both age- and sex-related disease progression. General neurological reflexive testing showed only acclimation to repeated testing by all groups. Yet, at 2.5 months of age, female Tg26 +/- mice showed hyposensitivity to noxious hot temperatures, compared to wild types (both sexes) and male Tg26 +/- mice, that worsened by 10 months of age. Female Tg26 +/- mice had short-term spatial memory losses in novel object location memory testing at 2.5 and 7 months, compared to female wild types; changes not observed in male counterparts. Female Tg26 +/- mice showed mild learning deficits and short- and long-term spatial memory deficits in olfactory and visually cued Barnes Maze testing at 3 months of age, yet greater learning and memory deficits by 8 months. In contrast, male Tg26 +/- mice displayed no learning deficits and fewer spatial memory deficits (mainly heading errors in nontarget holes). Thus, greater sex-specific temperature hyposensitivity and spatial memory declines were observed in female HIV Tg26 +/- mice, than in male Tg26 +/- mice, or their wild type littermates, that increased with aging. Additionally, tibial bones were examined using ex vivo micro-CT after tissue collection at 11 months. Sex-dependent increases in bone volume and trabecular number were seen in males, matching their greater weights at this age. These results indicate that HIV-1 Tg26 mice is a promising model in which to study neuropathic mechanisms underlying peripheral pathology as well as cognitive deficits seen with HIV.

HIV-1 Reverse Transcriptase Promotes Tumor Growth and Metastasis Formation via ROS-Dependent Upregulation of Twist

HIV-induced immune suppression results in the high prevalence of HIV/AIDS-associated malignancies including Kaposi sarcoma, non-Hodgkin lymphoma, and cervical cancer. HIV-infected people are also at an increased risk of “non-AIDS-defining” malignancies not directly linked to immune suppression but associated with viral infections. Their incidence is increasing despite successful antiretroviral therapy. The mechanism behind this phenomenon remains unclear. Here, we obtained daughter clones of murine mammary gland adenocarcinoma 4T1luc2 cells expressing consensus reverse transcriptase of HIV-1 subtype A FSU_A strain (RT_A) with and without primary mutations of drug resistance. In in vitro tests, mutations of resistance to nucleoside inhibitors K65R/M184V reduced the polymerase, and to nonnucleoside inhibitors K103N/G190S, the RNase H activities of RT_A. Expression of these RT_A variants in 4T1luc2 cells led to increased production of the reactive oxygen species (ROS), lipid peroxidation, enhanced cell motility in the wound healing assay, and upregulation of expression of Vimentin and Twist. These properties, particularly, the expression of Twist, correlated with the levels of expression RT_A and/or the production of ROS. When implanted into syngeneic BALB/C mice, 4T1luc2 cells expressing nonmutated RT_A demonstrated enhanced rate of tumor growth and increased metastatic activity, dependent on the level of expression of RT_A and Twist. No enhancement was observed for the clones expressing mutated RT_A variants. Plausible mechanisms are discussed involving differential interactions of mutated and nonmutated RTs with its cellular partners involved in the regulation of ROS. This study establishes links between the expression of HIV-1 RT, production of ROS, induction of EMT, and enhanced propagation of RT-expressing tumor cells. Such scenario can be proposed as one of the mechanisms of HIV-induced/enhanced carcinogenesis not associated with immune suppression.

Two Different Extranodal Lymphomas in an HIV+ Patient: A Case Report and Review of the Literature

Human immune deficiency virus- (HIV-) infected individuals present a higher risk of developing malignancies. Herein, we are presenting an unusual case of an untreated HIV+ patient, who developed two distinct lymphoproliferative disorders in a period of 4 years: a primary cutaneous T-cell lymphoma (PCTCL) and a diffuse large B-cell lymphoma (DLBCL) not otherwise specified (NOS), the latter developed while commencing combined antiretroviral therapy (cART). The two lymphomas also showed peculiar features: PCTCL are rarely described in HIV+ setting and particularly at such a low clinical stage, and the DLBCL showed uncommon cytology, non-GCB phenotype, EBER negativity, and absence of c-MYC translocation, all atypical features in this clinical context. This report not only confirms the increased risk of lymphoma for HIV+ patients and HIV infection being one of the major risk factors for lymphoid disorders but draws the attention on the possible occurrence of unusual features, suggesting that HIV serology should always be investigated in the clinical suspicion of lymphoma.

Caspase-1 Activation Is Related With HIV-Associated Atherosclerosis in an HIV Transgenic Mouse Model and HIV Patient Cohort

OBJECTIVE

Atherosclerotic cardiovascular disease (ASCVD) is an increasing cause of morbidity and mortality in people with HIV since the introduction of combination antiretroviral therapy. Despite recent advances in our understanding of HIV ASCVD, controversy still exists on whether this increased risk of ASCVD is due to chronic HIV infection or other risk factors. Mounting biomarker studies indicate a role of monocyte/macrophage activation in HIV ASCVD; however, little is known about the mechanisms through which HIV infection mediates monocyte/macrophage activation in such a way as to engender accelerated atherogenesis. Here, we experimentally investigated whether HIV expression is sufficient to accelerate atherosclerosis and evaluated the role of caspase-1 activation in monocytes/macrophages in HIV ASCVD. Approach and Results: We crossed a well-characterized HIV mouse model, Tg26 mice, which transgenically expresses HIV-1, with ApoE-/- mice to promote atherogenic conditions (Tg26+/-/ApoE-/-). Tg26+/-/ApoE-/- have accelerated atherosclerosis with increased caspase-1 pathway activation in inflammatory monocytes and atherosclerotic vasculature compared with ApoE-/-. Using a well-characterized cohort of people with HIV and tissue-banked aortic plaques, we documented that serum IL (interleukin)-18 was higher in people with HIV compared with non-HIV-infected controls, and in patients with plaques, IL-18 levels correlated with monocyte/macrophage activation markers and noncalcified inflammatory plaques. In autopsy-derived aortic plaques, caspase-1+ cells and CD (clusters of differentiation) 163+ macrophages correlated.

CONCLUSIONS

These data demonstrate that expression of HIV is sufficient to accelerate atherogenesis. Further, it highlights the importance of caspase-1 and monocyte/macrophage activation in HIV atherogenesis and the potential of Tg26+/-/ApoE-/- as a tool for mechanistic studies of HIV ASCVD.

Elevated indoleamine-2,3-dioxygenase enzyme activity in a novel mouse model of HIV-associated atherosclerosis

OBJECTIVE

HIV atherosclerosis and cardiovascular disease (CVD) represent a significant human health burden in the era of combination antiretroviral therapy (cART). The pathogenesis of HIV atherosclerosis is still poorly understood, due, in part, to the lack of a suitable small animal model. Indoleamine-2,3-dioxygenase (IDO) enzyme activity is the first and rate-limiting step in tryptophan catabolism and is measured by the kynurenine to tryptophan ratio (KTR). The serum KTR is a biomarker of inflammation and has recently been implicated as an important risk factor for CVD in patients living with HIV (PLWH) who are virologically suppressed under cART. However, IDO activity in HIV-associated CVD has not been studied in mouse model before.

DESIGN

A novel mouse model of HIV atherosclerosis (Tg26/ApoE) was generated and examined for IDO activity and atherogenesis throughout 8 weeks on a high-fat diet. Tg26/ApoE mice were compared with Tg26 and ApoE single transgenic mice, before and during a high-fat diet.

METHOD

Serum kynurenine, tryptophan and percentage of aortic plaque formation were measured. Additionally, levels of relevant cytokines were investigated in Tg26/ApoE and ApoE.

RESULTS

Tg26/ApoE developed an accelerated atherosclerosis with increasing levels of KTR that were associated with plaque progression. This accelerated plaque was potentially driven by elevated levels of circulating IL-6.

CONCLUSION

These results indicate that Tg26/ApoE serve as a new mouse model for HIV-induced atherogenesis, and aid in understanding the role of tryptophan catabolism in the pathogenesis of HIV atherosclerosis/CVD.

Sex-specific neurogenic deficits and neurocognitive disorders in middle-aged HIV-1 Tg26 transgenic mice

Varying degrees of cognitive deficits affect over half of all HIV-1 infected patients. Because of antiretroviral treatment (ART) regimens, the HIV-1 patient population is increasing in age. Very few epidemiological studies have focused on sex-specific differences in HIV-1-associated neurocognitive disorders (HAND). The purpose of this study is to examine any possible differences between male and female mice in the progression of cognitive dementia during persistent low-level HIV-1 protein exposure, mimicking the typical clinical setting in the post-ART era. Eight to ten-month old HIV-1 Tg26(+/-) transgenic mice were utilized to assess for specific learning and memory modalities. Initial physiological screening and fear conditioning assessments revealed that Tg26 mice exhibited no significant differences in general behavioral function, contextual fear conditioning, or cued fear conditioning responses when compared to their wild-type (WT) littermates, regardless of sex. However, Barnes maze testing revealed significantly impaired short and long-term spatial memory in males, while females had impaired spatial learning abilities and short-term spatial memory. The potential cellular mechanism underlying these sex-specific neurocognitive deficits was explored with hippocampal neurogenic analysis. Compared to WT mice, both male and female Tg26(+/-) mice had fewer quiescent neural stem cells and neuroblasts in their hippocampi. Male Tg26(+/-) mice had a more robust reduction of the quiescent neural stem cell pool than female Tg26(+/-) mice. While female WT mice had a higher number of neural progenitor cells than male WT mice, only female Tg26(+/-) mice exhibited a robust reduction in the number of neural progenitor cells. Altogether, these results suggest that middle-aged male and female Tg26(+/-) mice manifest differing impairments in cognitive functioning and hippocampal neurogenesis. This study emphasizes the importance of understanding sex related differences in HAND pathology, which would aid in designing more optimized therapeutic regimens for the treatment of HAND.

HIV biosensors for early diagnosis of infection: The intertwine of nanotechnology with sensing strategies

Human immunodeficiency virus (HIV) is a lentivirus that leads to acquired immunodeficiency syndrome (AIDS). With increasing awareness of AIDS emerging as a global public health threat, different HIV testing kits have been developed to detect antibodies (Ab) directed toward different parts of HIV. A great limitation of these tests is that they can not detect HIV antibodies during early virus infection. Therefore, to overcome this challenge, a wide range of biosensors have been developed for early diagnosis of HIV infection. A significant amount of these studies have been focused on the application of nanomaterials for improving the sensitivity and accuracy of the sensing methods. Following an introduction into this field, a first section of this review covers the synthesis and applicability of such nanomaterials as metal nanoparticles (NPs), quantum dots (QDs), carbon-based nanomaterials and metal nanoclusters (NCs). A second larger section covers the latest developments concerning nanomaterial-based biosensors for HIV diagnosis, with paying a special attention to the determination of CD4⁺ cells as a hall mark of HIV infection, HIV gene, HIV p24 core protein, HIV p17 peptide, HIV-1 virus-like particles (VLPs) and HIV related enzymes, particularly those that are passed on from the virus to the CD⁴⁺ T lymphocytes and are necessary for viral reproduction within the host cell. These studies are described in detail along with their diverse principles/mechanisms (e.g. electrochemistry, fluorescence, electromagnetic-piezoelectric, surface plasmon resonance (SPR), surface enhanced Raman spectroscopy (SERS) and colorimetry). Despite the significant progress in HIV biosensing in the last years, there is a great need for the development of point-of-care (POC) technologies which are affordable, robust, easy to use, portable, and possessing sufficient quantitative accuracy to enable clinical decision making. In the final section, the focus is on the portable sensing devices as a new standard of POC and personalized diagnostics.

A replication-incompetent CD154/40L recombinant vaccinia virus induces direct and macrophage-mediated antitumor effects in vitro and in vivo

CD40 triggering may result in antitumor effects of potentially high clinical relevance. To gain insights important for patient selection and to identify adequate targeting techniques, we investigated CD40 expression in human cancer tissues and generated a replication-incompetent recombinant vaccinia virus expressing CD40 ligand (rVV40L). Its effects were explored in vitro and in vivo upon direct CD40 targeting on malignant cells or macrophage activation. CD40 expression was analyzed by immunohistochemistry in tumor and stromal cells in a multi-tumor array including 836 specimens from 27 different tumor types. Established tumor cell lines were used to explore the capacity of rVV40L to induce malignant cell apoptosis and modulate functional profiles of polarized macrophages. CD40 expression was detectable in significantly higher numbers of stromal as compared to malignant cells in lung and breast cancers. CD40 ligation following rVV40L infection induced apoptosis in CD40(+) cancer cells, but only in the presence of intact specific signal transduction chain. Importantly, rVV40L infection promoted the induction of TNF-α-dependent antitumor activity of M1-like macrophages directed against CD40(-) targets. CD40-activated M1-like macrophages also displayed enhanced ability to CXCL10-dependently recruit CD8+ T cells and to efficiently present cancer cell intracellular antigens through cross-priming. Moreover, rVV-driven CD40L expression partially “re-educated” M2-like macrophages, as suggested by detectable CXCL10 and IL-12 production. Most importantly, we observed that intra-tumoral injection of rVV40L-infected human macrophages inhibits progression of human CD40(-) tumors in vivo. First evidences of anticancer activity of rVV40L strongly encourage further evaluations.

Role of the inflammasomes in HIV-associated neuroinflammation and neurocognitive disorders

HIV associated neurocognitive disorders (HAND) is a unique form of neurological impairment that stems from HIV. This disease and its characteristics can be accredited to incorporation of DNA and mRNA of HIV-1 into the CNS. A proper understanding of the intricacies of HAND and the underlying mechanisms associated with corresponding immune reactions are vital for the potential development of a reliable treatment for HAND. A common phenomenon observed in CNS cells, specifically microglia, that are infected with HAND is inflammation, which is a consequence of the activation of innate immune response due to a variety of stimuli, in this case, being the HIV infection. The CNS based inflammation is mediated by the production of cytokines, chemokines, reactive oxygen species, and secondary messengers, which occurs at CNS glia, endothelial cells and peripherally derived immune cells. Inflammasomes play a significant role with regard to neuroinflammation due to their ability to dictate the activation of various inflammatory responses. Certain stimuli can result in the activation of caspase-1; hence, leading to the processing of interleukin-1β and interleukin-18 pro-inflammatory cytokines. The processed IL-1β and IL-18 activate signaling pathways that begin the process of neuroinflammation. Due to the fact that the NLRP3 inflammasome is the most abundant in the CNS, it is the most extensively investigated inflammasome with regard to the nervous system. Due to the importance of neuroinflammation in the evolution of HAND and proliferation of neuroinflammation due to HAND, it can be concluded that there exists a relationship between HAND and inflammasomes. The aim of our review is to consolidate current knowledge of important mechanisms in HAND, specifically related to its relationship with neuroinflammation and inflammasomes to shed light on a possible improved treatment for HAND.

Lymphomagenic properties of a HIV p17 variant derived from a splenic marginal zone lymphoma occurred in a HIV-infected patient

Despite antiretroviral therapy, HIV+ individuals still have increased risk to develop lymphomas, including marginal zone lymphomas, suggesting that factors other than HIV-related immunosuppression are probably acting as lymphomagenic factors in the HIV setting. The possible pathogenic involvement of HIV p17 protein variants was investigated in a particularly informative case of HIV-related splenic marginal zone lymphoma, which was negative for oncogenic virus infections, thus allowing us to assess the possible direct contribution of these HIV-encoded proteins to lymphomagenesis. The presence of p17 protein was analyzed by immunohistochemistry in lymphoma tissue. Recombinant p17 protein derived from the dominant sequence detected in plasma and lymphoma biopsy was characterized for B-cell proliferation, clonogenicity in soft agar, in vitro tube formation and wound healing. Intracellular signaling was investigated by immunoblotting. HIV p17 protein was detected in reactive lymphoid follicles but not within lymphoma cells. An identical dominant variant p17 sequence, p17-Lyrm, carrying a 117 to 118 Ala-Ala insertion was detected in both plasma and lymphoma tissue. Recombinant p17-Lyrm enhanced B-cell proliferation and clonogenicity promoted the formation of capillary-like structures and enhanced endothelial cell migration. Unlike reference p17, the p17-Lyrm variant enhanced the activation of Akt and ERK, critical kinases in lymphomagenesis. p17-Lyrm clonogenic activity was dependent on the activation of Akt but not of ERK1/2. These results indicated that HIV p17 variants with distinct molecular signatures and functional properties may accumulate in lymphoid tissues of HIV-infected individuals where they may act as a local stimulus promoting the development of lymphomas.

Adult neurogenic deficits in HIV-1 Tg26 transgenic mice

Background

Even in the antiretroviral treatment (ART) era, HIV-1-infected patients suffer from milder forms of HIV-1-associated neurocognitive disorders (HAND). While the viral proteins Tat and gp120 have been shown to individually inhibit the proliferation and neural differentiation of neural stem cells (NSCs), no studies have characterized the effects of all the combined viral proteins on adult neurogenesis.

Methods

The HIV-1 Tg26 transgenic mouse model was used due to its clinical relevance to ART-controlled HIV-1-infected patients who lack active viral replication but suffer from continuous stress from the viral proteins. Quantitative RT-PCR analysis was performed to validate the expression of viral genes in the neurogenic zones. In vitro stemness and lineage differentiation assays were performed in cultured NSCs from HIV-1 Tg26 transgenic mice and their wild-type littermates. Hippocampal neurogenic lineage analysis was performed to determine potential changes in initial and late differentiation of NSCs in the subgranular zone (SGZ). Finally, fluorescent retroviral labeling of mature dentate granule neurons was performed to assess dendritic complexity and dendritic spine densities.

Results

Varying copy numbers of partial gag (p17), tat (unspliced and spliced variants), env (gp120), vpu, and nef transcripts were detected in the neurogenic zones of Tg26 mice. Significantly fewer primary neurospheres and a higher percentage of larger sized primary neurospheres were generated from Tg26 NSCs than from littermated wild-type mouse NSCs, implying that Tg26 mouse NSCs exhibit deficits in initial differentiation. In vitro differentiation assays revealed that Tg26 mouse NSCs have reduced neuronal differentiation and increased astrocytic differentiation. In the SGZs of Tg26 mice, significantly higher amounts of quiescent NSCs, as well as significantly lower levels of active NSCs, proliferating neural progenitor cells, and neuroblasts, were observed. Finally, newborn mature granule neurons in the dentate gyri of Tg26 mice had deficiencies in dendritic arborization, dendritic length, and dendritic spine density.

Conclusions

Both in vitro and in vivo studies demonstrate that HIV-1 Tg26 mice have early- and late-stage neurogenesis deficits, which could possibly contribute to the progression of HAND. Future therapies should be targeting this process to ameliorate, if not eliminate HAND-like symptoms in HIV-1-infected patients.

Identification of amino acid residues critical for the B cell growth-promoting activity of HIV-1 matrix protein p17 variants

BACKGROUND

HIV-1 matrix protein p17 variants (vp17s) detected in HIV-1-infected patients with non-Hodgkin's lymphoma (HIV-NHL) display, differently from the wild-type protein (refp17), B cell growth-promoting activity. Biophysical analysis revealed that vp17s are destabilized as compared to refp17, motivating us to explore structure-function relationships.

METHODS

We used: biophysical techniques (circular dichroism (CD), nuclear magnetic resonance (NMR) and thermal/GuHCL denaturation) to study protein conformation and stability; Surface plasmon resonance (SPR) to study interactions; Western blot to investigate signaling pathways; and Colony Formation and Soft Agar assays to study B cell proliferation and clonogenicity.

RESULTS

By forcing the formation of a disulfide bridge between Cys residues at positions 57 and 87 we obtained a destabilized p17 capable of promoting B cell proliferation. This finding prompted us to dissect refp17 to identify the functional epitope. A synthetic peptide (F1) spanning from amino acid (aa) 2 to 21 was found to activate Akt and promote B cell proliferation and clonogenicity. Three positively charged aa (Arg15, Lys18 and Arg20) proved critical for sustaining the proliferative activity of both F1 and HIV-NHL-derived vp17s. Lack of any interaction of F1 with the known refp17 receptors suggests an alternate one involved in cell proliferation.

CONCLUSIONS

The molecular reasons for the proliferative activity of vp17s, compared to refp17, relies on the exposure of a functional epitope capable of activating Akt.

GENERAL SIGNIFICANCE

Our findings pave the way for identifying the receptor(s) responsible for B cell proliferation and offer new opportunities to identify novel treatment strategies in combating HIV-related NHL.

HIV-1 matrix protein p17 and its variants promote human triple negative breast cancer cell aggressiveness

Background

The introduction of cART has changed the morbidity and mortality patterns affecting HIV-infected (HIV⁺) individuals. The risk of breast cancer in HIV⁺ patients has now approached the general population risk. However, breast cancer has a more aggressive clinical course and poorer outcome in HIV⁺ patients than in general population, without correlation with the CD4 or virus particles count. These findings suggest a likely influence of HIV-1 proteins on breast cancer aggressiveness and progression. The HIV-1 matrix protein (p17) is expressed in different tissues and organs of successfully cART-treated patients and promotes migration of different cells. Variants of p17 (vp17s), characterized by mutations and amino acid insertions, differently from the prototype p17 (refp17), also promote B-cell proliferation and transformation.

Methods

Wound-healing assay, matrigel-based invasion assay, and anchorage-independent proliferation assay were employed to compare the biological activity exerted by refp17 and three different vp17s on the triple-negative human breast cancer cell line MDA-MB 231. Intracellular signaling was investigated by western blot analysis.

Results

Motility and invasiveness increased in cells treated with both refp17 and vp17s compared to untreated cells. The effects of the viral proteins were mediated by binding to the chemokine receptor CXCR2 and activation of the ERK1/2 signaling pathway. However, vp17s promoted MDA-MB 231 cell growth and proliferation in contrast to refp17-treated or not treated cells.

Conclusions

In the context of the emerging role of the microenvironment in promoting and supporting cancer cell growth and metastatic spreading, here we provide the first evidence that exogenous p17 may play a crucial role in sustaining breast cancer cell migration and invasiveness, whereas some p17 variants may also be involved in cancer cell growth and proliferation.

Role of Autophagy in HIV-1 Matrix Protein p17-Driven Lymphangiogenesis

AIDS-related lymphomas (ARLs) are expected to increase in the future since combined antiretroviral therapy (cART) enhances the life expectancy of HIV-1-infected (HIV⁺) patients but does not affect the occurrence of ARLs to the same extent as that of other tumors. Lymphangiogenesis is essential in supporting growth and metastatic spreading of ARLs. HIV-1 does not infect the neoplastic B cells, but HIV-1 proteins have been hypothesized to play a key role in sustaining a prolymphangiogenic microenvironment in lymphoid organs. The HIV-1 matrix protein p17 is detected in blood and accumulates in the germinal centers of lymph nodes of HIV⁺ patients under successful cART. The viral protein displays potent lymphangiogenic activity in vitro and in vivo This is, at least in part, mediated by the secretion of the lymphangiogenic factor endothelin-1, suggesting that activation of a secretory pathway sustains the lymphangiogenic activity of p17. Here, we show that the p17 lymphangiogenic activity occurs on human lymph node-derived lymphatic endothelial cells (LN-LECs) under stress conditions only and relies entirely on activation of an autophagy-based pathway. In fact, induction of autophagy by p17 promotes lymphangiogenesis, whereas pharmacological and genetic inhibition of autophagy inhibits p17-triggered lymphangiogenesis. Similarly, the vasculogenic activity of p17 was totally inhibited in autophagy-incompetent mice. Our findings reveal a previously unrecognized role of autophagy in lymphangiogenesis and open the way to identify novel treatment strategies aimed at inhibiting aberrant tumor-driven lymphangiogenesis in HIV⁺ patients.IMPORTANCE AIDS-related lymphomas (ARLs) are the most common malignancies in HIV-1-infected (HIV⁺) patients after the introduction of combined antiretroviral therapy (cART). Lymphangiogenesis is of critical importance in sustaining growth and metastasis of ARLs. Indeed, enhanced lymphangiogenesis occurs in the lymph nodes of HIV⁺ patients under successful cART. The HIV-1 matrix protein p17 is detected in blood and accumulates in the lymph node germinal centers even in the absence of virus replication. Several findings suggest a key role for p17 as a microenvironmental factor capable of promoting lymphangiogenesis. Here, we show that p17 promotes lymphangiogenesis of human lymph node-derived lymphatic endothelial cells (LN-LECs). The lymphangiogenic activity of p17 is sustained by an autophagy-based pathway that enables LN-LECs to release prolymphangiogenic factors into the extracellular microenvironment. Our findings indicate that specific targeting of autophagy may provide an important new tool for treating ARLs.

A single amino acid substitution confers B-cell clonogenic activity to the HIV-1 matrix protein p17

Recent data highlight the presence, in HIV-1-seropositive patients with lymphoma, of p17 variants (vp17s) endowed with B-cell clonogenicity, suggesting a role of vp17s in lymphomagenesis. We investigated the mechanisms responsible for the functional disparity on B cells between a wild-type p17 (refp17) and a vp17 named S75X. Here, we show that a single Arginine (R) to Glycine (G) mutation at position 76 in the refp17 backbone (p17R76G), as in the S75X variant, is per se sufficient to confer a B-cell clonogenic potential to the viral protein and modulate, through activation of the PTEN/PI3K/Akt signaling pathway, different molecules involved in apoptosis inhibition (CASP-9, CASP-7, DFF-45, NPM, YWHAZ, Src, PAX2, MAPK8), cell cycle promotion and cancer progression (CDK1, CDK2, CDK8, CHEK1, CHEK2, GSK-3 beta, NPM, PAK1, PP2C-alpha). Moreover, the only R to G mutation at position 76 was found to strongly impact on protein folding and oligomerization by altering the hydrogen bond network. This generates a conformational shift in the p17 R76G mutant which enables a functional epitope(s), masked in refp17, to elicit B-cell growth-promoting signals after its interaction with a still unknown receptor(s). Our findings offer new opportunities to understand the molecular mechanisms accounting for the B-cell growth-promoting activity of vp17s.