Dasatinib protects humanized mice from acute HIV-1 infection

Targeting Viral Transcription for HIV Cure Strategies

Combination antiretroviral therapy (ART) suppresses viral replication to undetectable levels, reduces mortality and morbidity, and improves the quality of life of people living with HIV (PWH). However, ART cannot cure HIV infection because it is unable to eliminate latently infected cells. HIV latency may be regulated by different HIV transcription mechanisms, such as blocks to initiation, elongation, and post-transcriptional processes. Several latency-reversing (LRA) and -promoting agents (LPA) have been investigated in clinical trials aiming to eliminate or reduce the HIV reservoir. However, none of these trials has shown a conclusive impact on the HIV reservoir. Here, we review the cellular and viral factors that regulate HIV-1 transcription, the potential pharmacological targets and genetic and epigenetic editing techniques that have been or might be evaluated to disrupt HIV-1 latency, the role of miRNA in post-transcriptional regulation of HIV-1, and the differences between the mechanisms regulating HIV-1 and HIV-2 expression.

Emerging roles of senolytics/senomorphics in HIV-related co-morbidities

Human immunodeficiency virus (HIV) is known to cause cellular senescence and inflammation among infected individuals. While the traditional antiretroviral therapies (ART) have allowed the once fatal infection to be managed effectively, the quality of life of HIV patients on prolonged ART use is still inferior. Most of these individuals suffer from life-threatening comorbidities like chronic obstructive pulmonary disease (COPD), pulmonary arterial hypertension (PAH), and diabetes, to name a few. Interestingly, cellular senescence is known to play a critical role in the pathophysiology of these comorbidities as well. It is therefore important to understand the role of cellular senescence in the disease progression and co-morbidity development in HIV-infected individuals. In this respect, use of senolytic/senomorphic drugs as combination therapy with ART would be beneficial for HIV patients. This review provides a critical analysis of the current literature to determine the potential and efficacy of using senolytics/senotherapeutics in managing HIV infection, latency, and associated co-morbidities in humans. The various classes of senolytics have been studied in detail to focus on their potential to combat against HIV infections and associated pathologies with advancing age.

Dasatinib: a potential tyrosine kinase inhibitor to fight against multiple cancer malignancies

Dasatinib is the 2nd generation TKI (Tyrosine Kinase Inhibitor) having the potential to treat numerous forms of leukemic and cancer patients and it is 300 times more potent than imatinib. Cancer is the major cause of death globally and need to enumerate novel strategies to coping with it. Various novel therapeutics introduced into the market for ease in treating various forms of cancer. We reviewed and evaluated all the related aspects of dasatinib, which can enhance the knowledge about dasatinib therapeutics methodology, pharmacodynamic and pharmacokinetics, side effects, advantages, disadvantages, various kinds of interactions and its novel formulations as well.

Chikungunya virus time course infection of human macrophages reveals intracellular signaling pathways relevant to repurposed therapeutics

Background

Chikungunya virus (CHIKV) is a mosquito-borne pathogen, within the Alphavirus genus of the Togaviridae family, that causes ~1.1 million human infections annually. CHIKV uses Aedes albopictus and Aedes aegypti mosquitoes as insect vectors. Human infections can develop arthralgia and myalgia, which results in debilitating pain for weeks, months, and even years after acute infection. No therapeutic treatments or vaccines currently exist for many alphaviruses, including CHIKV. Targeting the phagocytosis of CHIKV by macrophages after mosquito transmission plays an important role in early productive viral infection in humans, and could reduce viral replication and/or symptoms.

Methods

To better characterize the transcriptional response of macrophages during early infection, we generated RNA-sequencing data from a CHIKV-infected human macrophage cell line at eight or 24 hours post-infection (hpi), together with mock-infected controls. We then calculated differential gene expression, enriched functional annotations, modulated intracellular signaling pathways, and predicted therapeutic drugs from these sequencing data.

Results

We observed 234 pathways were significantly affected 24 hpi, resulting in six potential pharmaceutical treatments to modulate the affected pathways. A subset of significant pathways at 24 hpi includes AGE-RAGE, Fc epsilon RI, Chronic myeloid leukemia, Fc gamma R-mediated phagocytosis, and Ras signaling. We found that the MAPK1 and MAPK3 proteins are shared among this subset of pathways and that Telmisartan and Dasatinib are strong candidates for repurposed small molecule therapeutics that target human processes. The results of our analysis can be further characterized in the wet lab to contribute to the development of host-based prophylactics and therapeutics.

Potential Applications and Perspectives of Humanized Mouse Models

As medical and pharmacological technology advances, new and complex modalities of disease treatment that are more personalized and targeted are being developed. Often these modalities must be validated in the presence of critical components of the human biological system. Given the incongruencies between murine and human biology, as well as the human-tropism of certain drugs and pathogens, the selection of animal models that accurately recapitulate the intricacies of the human biological system becomes more salient for disease modeling and preclinical testing. Immunodeficient mice engrafted with functional human tissues (so-called humanized mice), which allow for the study of physiologically relevant disease mechanisms, have thus become an integral aspect of biomedical research. This review discusses the recent advancements and applications of humanized mouse models on human immune system and liver humanization in modeling human diseases, as well as how they can facilitate translational medicine.

Co-receptor signaling in the pathogenesis of neuroHIV

The HIV co-receptors, CCR5 and CXCR4, are necessary for HIV entry into target cells, interacting with the HIV envelope protein, gp120, to initiate several signaling cascades thought to be important to the entry process. Co-receptor signaling may also promote the development of neuroHIV by contributing to both persistent neuroinflammation and indirect neurotoxicity. But despite the critical importance of CXCR4 and CCR5 signaling to HIV pathogenesis, there is only one therapeutic (the CCR5 inhibitor Maraviroc) that targets these receptors. Moreover, our understanding of co-receptor signaling in the specific context of neuroHIV is relatively poor. Research into co-receptor signaling has largely stalled in the past decade, possibly owing to the complexity of the signaling cascades and functions mediated by these receptors. Examining the many signaling pathways triggered by co-receptor activation has been challenging due to the lack of specific molecular tools targeting many of the proteins involved in these pathways and the wide array of model systems used across these experiments. Studies examining the impact of co-receptor signaling on HIV neuropathogenesis often show activation of multiple overlapping pathways by similar stimuli, leading to contradictory data on the effects of co-receptor activation. To address this, we will broadly review HIV infection and neuropathogenesis, examine different co-receptor mediated signaling pathways and functions, then discuss the HIV mediated signaling and the differences between activation induced by HIV and cognate ligands. We will assess the specific effects of co-receptor activation on neuropathogenesis, focusing on neuroinflammation. We will also explore how the use of substances of abuse, which are highly prevalent in people living with HIV, can exacerbate the neuropathogenic effects of co-receptor signaling. Finally, we will discuss the current state of therapeutics targeting co-receptors, highlighting challenges the field has faced and areas in which research into co-receptor signaling would yield the most therapeutic benefit in the context of HIV infection. This discussion will provide a comprehensive overview of what is known and what remains to be explored in regard to co-receptor signaling and HIV infection, and will emphasize the potential value of HIV co-receptors as a target for future therapeutic development.

Treatment-Free Remission-A New Aim in the Treatment of Chronic Myeloid Leukemia

Tyrosine kinases inhibitors (TKIs) revolutionized chronic myeloid leukemia (CML) treatment for many years, prolonging patients' life expectancy to be comparable to age-matched healthy individuals. According to the latest the European LeukemiaNet (ELN) recommendations, CML treatment aims to achieve long-term remission without treatment (TFR), which is feasible in more than 40% of patients. Nearly all molecular relapses occur during the first 6 months after TKI withdrawal and do not progress to clinical relapse. The mechanisms that are responsible for CML relapses remain unexplained. It is suggested that maintaining TFR is not directly related to the total disposing of the gene transcript BCR-ABL1, but it might be a result of the restoration of the immune surveillance in CML. The importance of the involvement of immunocompetent cells in the period of TKI withdrawal is also emphasized by the presence of specific symptoms in some patients with "withdrawal syndrome". The goal of this review is to analyze data from studies regarding TFRs in order to characterize the elements of the immune system of patients that might prevent CML molecular relapse. The role of modern droplet digital polymerase chain reaction (ddPCR) and next-generation sequencing (NGS) in better identification of low levels of BCR-ABL1 transcripts was also taken into consideration for refining the eligibility criteria to stop TKI therapy.

Provirus reactivation is impaired in HIV-1 infected individuals on treatment with dasatinib and antiretroviral therapy

The latent viral reservoir formed by HIV-1, mainly in CD4 + T cells, is responsible for the failure of antiretroviral therapy (ART) to achieve a complete elimination of the virus in infected individuals. We previously determined that CD4 + T cells from individuals with chronic myeloid leukemia (CML) on treatment with dasatinib are resistant to HIV-1 infection ex vivo. The main mechanism for this antiviral effect is the preservation of SAMHD1 activity. In this study, we aimed to evaluate the impact of dasatinib on the viral reservoir of HIV-infected individuals with CML who were on simultaneous treatment with ART and dasatinib. Due to the low estimated incidence of HIV-1 infection and CML (1:65,000), three male individuals were recruited in Spain and Germany. These individuals had been on treatment with standard ART and dasatinib for median 1.3 years (IQR 1.3-5.3 years). Reservoir size and composition in PBMCs from these individuals was analyzed in comparison with HIV-infected individuals on triple ART regimen and undetectable viremia. The frequency of latently infected cells was reduced more than 5-fold in these individuals. The reactivation of proviruses from these cells was reduced more than 4-fold and, upon activation, SAMHD1 phosphorylation was reduced 40-fold. Plasma levels of the homeostatic cytokine IL-7 and CD4 effector subpopulations TEM and TEMRA in peripheral blood were also reduced. Therefore, treatment of HIV-infected individuals with dasatinib as adjuvant of ART could disturb the reservoir reactivation and reseeding, which might have a beneficial impact to reduce its size.

Identification of candidate repurposable drugs to combat COVID-19 using a signature-based approach

The COVID-19 pandemic caused by the novel SARS-CoV-2 is more contagious than other coronaviruses and has higher rates of mortality than influenza. Identification of effective therapeutics is a crucial tool to treat those infected with SARS-CoV-2 and limit the spread of this novel disease globally. We deployed a bioinformatics workflow to identify candidate drugs for the treatment of COVID-19. Using an "omics" repository, the Library of Integrated Network-Based Cellular Signatures (LINCS), we simultaneously probed transcriptomic signatures of putative COVID-19 drugs and publicly available SARS-CoV-2 infected cell lines to identify novel therapeutics. We identified a shortlist of 20 candidate drugs: 8 are already under trial for the treatment of COVID-19, the remaining 12 have antiviral properties and 6 have antiviral efficacy against coronaviruses specifically, in vitro. All candidate drugs are either FDA approved or are under investigation. Our candidate drug findings are discordant with (i.e., reverse) SARS-CoV-2 transcriptome signatures generated in vitro, and a subset are also identified in transcriptome signatures generated from COVID-19 patient samples, like the MEK inhibitor selumetinib. Overall, our findings provide additional support for drugs that are already being explored as therapeutic agents for the treatment of COVID-19 and identify promising novel targets that are worthy of further investigation.

The Interaction of Viruses with the Cellular Senescence Response

Cellular senescence is viewed as a mechanism to prevent malignant transformation, but when it is chronic, as occurs in age-related diseases, it may have adverse effects on cancer. Therefore, targeting senescent cells is a novel therapeutic strategy against senescence-associated diseases. In addition to its role in cancer protection, cellular senescence is also considered a mechanism to control virus replication. Both interferon treatment and some viral infections can trigger cellular senescence as a way to restrict virus replication. However, activation of the cellular senescence program is linked to the alteration of different pathways, which can be exploited by some viruses to improve their replication. It is, therefore, important to understand the potential impact of senolytic agents on viral propagation. Here we focus on the relationship between virus and cellular senescence and the reported effects of senolytic compounds on virus replication.

Senotherapeutics and HIV-1 Persistence

PURPOSE OF REVIEW

To review the potential use of senotherapeutics, pharmacologic agents that target senescent cells, in addressing HIV-1 persistence.

RECENT FINDINGS

Treated HIV-1 infection results in a state of immune exhaustion, which may involve reprogramming of infected and bystander cells toward a state of cellular senescence. Aging research has recently uncovered pathways that make senescent cells uniquely susceptible to pharmacologic intervention. Specific compounds, known as senotherapeutics, have been identified that interrupt pathways senescent cells depend on for survival. Several of these pathways are important in modulating the cellular microenvironment in chronically and latently infected cells. Strategies targeting these pathways may prove useful in combating both HIV-1 persistence and HIV-1-associated immune exhaustion. Senotherapeutics have recently been described as potential therapeutics for aging-associated diseases driven by senescent cells. Recently, correlations have emerged between HIV-1 infection, senescence, lifelong chronic infection, and viral persistence. New insights and therapies targeting cellular senescence may offer a novel strategy to address both HIV-1 persistence and immune exhaustion induced by chronic viral infection.

Cytotoxic cell populations developed during treatment with tyrosine kinase inhibitors protect autologous CD4+ T cells from HIV-1 infection

Tyrosine kinase inhibitors (TKIs) are successfully used in clinic to treat chronic myeloid leukemia (CML). Our group previously described that CD4+ T cells from patients with CML on treatment with TKIs such as dasatinib were resistant to HIV-1 infection ex vivo. The main mechanism for this antiviral activity was primarily based on the inhibition of SAMHD1 phosphorylation, which preserves the activity against HIV-1 of this innate immune factor. Approximately 50% CML patients who achieved a deep molecular response (DMR) may safely withdraw TKI treatment without molecular recurrence. Therefore, it has been speculated that TKIs may induce a potent antileukemic response that is maintained in most patients even one year after treatment interruption (TI). Subsequent to in vitro T-cell activation, we observed that SAMHD1 was phosphorylated in CD4+ T cells from CML patients who withdrew TKI treatment more than one year earlier, which indicated that these cells were now susceptible to HIV-1 infection. Importantly, these patients were seronegative for HIV-1 and seropositive for cytomegalovirus (CMV), but without CMV viremia. Although activated CD4+ T cells from CML patients on TI were apparently permissive to HIV-1 infection ex vivo, the frequency of proviral integration was reduced more than 12-fold on average when these cells were infected ex vivo in comparison with cells isolated from untreated, healthy donors. This reduced susceptibility to infection could be related to an enhanced NK-dependent cytotoxic activity, which was increased 8-fold on average when CD4+ T cells were infected ex vivo with HIV-1 in the presence of autologous NK cells. Enhanced cytotoxic activity was also observed in CD8 + T cells from these patients, which showed 8-fold increased expression of TCRγδ and more than 18-fold increased production of IFNγ upon activation with CMV peptides. In conclusion, treatment with TKIs induced a potent antileukemic response that may also have antiviral effects against HIV-1 and CMV, suggesting that transient use of TKIs in HIV-infected patients could develop a sustained antiviral response that would potentially interfere with HIV-1 reservoir dynamics.

Dasatinib inhibits peripapillary scleral myofibroblast differentiation

Scleral fibroblast activation occurs in glaucomatous and myopic eyes. Here we perform an unbiased screen to identify kinase inhibitors that reduce fibroblast activation to diverse stimuli in vitro and to in vivo intraocular pressure (IOP) elevation. Primary cultures of peripapillary scleral (PPS) fibroblasts from two human donors were screened using a library of 80 kinase inhibitors to identify compounds that inhibit TGFβ-induced extracellular matrix (ECM) synthesis. Inhibition of myofibroblast differentiation was verified by alpha smooth muscle actin (αSMA) immunoblot and collagen contraction assay. Inhibition of IOP-induced scleral fibroblast proliferation was assessed by ELISA assay for proliferating cell nuclear antigen (PCNA). The initial screen identified 7 inhibitors as showing>80% reduction in ECM binding. Three kinase inhibitors were verified to reduce TGFβ-induced αSMA expression and cellular contractility (rottlerin, PP2, tyrphostin 9). The effect of three Src inhibitors, bosutinib, dasatinib, and SU-6656, on myofibroblast differentiation was evaluated, with only dasatinib significantly inhibiting TGFβ-induced ECM synthesis, αSMA expression, and cellular contractility at nanomolar dosages. Subconjunctival injection of dasatinib reduced IOP-induced scleral fibroblast proliferation compared to control (4.9 ± 11.1 ng/sclera with 0.1 μM versus 88.7 ± 38.6 ng/sclera in control, P < 0.0001). Dasatinib inhibits scleral myofibroblast differentiation and there is pharmacologic evidence that this inhibition is not solely due to Src-kinase inhibition.

Immunomodulatory Activity of Tyrosine Kinase Inhibitors to Elicit Cytotoxicity Against Cancer and Viral Infection

Tyrosine kinase inhibitors (TKIs) of aberrant tyrosine kinase (TK) activity have been widely used to treat chronic myeloid leukemia (CML) for decades in clinic. An area of growing interest is the reported ability of TKIs to induce immunomodulatory effects with anti-tumor and anti-viral activity, which appears to be mediated by directly or indirectly acting on immune cells. In selected cases of patients with CML, TKI treatment may be interrupted and a non-drug remission may be observed. In these patients, an immune mechanism of increased anti-tumor cytotoxic activity induced by chronic administration of TKIs has been suggested. TKIs increase some populations of natural killer (NK), NK-LGL, and T-LGLs cells especially in dasatinib treated CML patients infected with cytomegalovirus (CMV). In addition, dasatinib increases responses against CMV and is able to inhibit HIV replication in vitro. Recent studies suggest that subclinical reactivation of CMV could drive expansion of specific subsets of NK- and T-cells with both anti-tumoral and anti-viral function. Therefore, the underlying mechanisms implicated in the expansion of this increased anti-tumor and anti-viral cytotoxic activity induced by TKIs could be a new therapeutic approach to take into account against cancer and viral infections such as HIV-1 infection. The present review will briefly summarize the immunomodulatory effects of TKIs on T cells, NKs, and B cells. Therapeutic implications for modulating immunity against cancer and viral infections and critical open questions are also discussed.