Biology subjects

Zhen, A.

Publications and source records attributed to Zhen, A..

8 recordsLinked to original sources

bioRxiv2026

Leveraging HIV-Specific CAR T Cells and Rapamycin Treatment in Kick-and-Kill HIV Cure Approaches

HIV is not cured with currently available combination antiretroviral therapy (ART) alone in large part because the virus establishes virologic latency in long lived CD4+ cells. To eliminate this latent reservoir, as required for HIV eradication, latency reversing agents (LRAs) are being developed to force HIV out of latency and induce infected cells to express viral proteins leading to their clearance, in a so-called "Kick-and-Kill" approach. This strategy relies on the immune system to clear the productively-infected cells and is thus limited by HIV immune evasion and the immunological exhaustion that occurs during HIV infection. To counter these limitations and augment an LRA-mediated HIV cure approach, we report herein the utility of HIV-specific truncated CD4-based D1D2 CAR T cells combined with LRA treatment and the mTORC1 inhibitor rapamycin to reduce immune exhaustion and specifically target and kill LRA-stimulated HIV infected cells. We demonstrate that rapamycin does not prevent HIV latency reversal via multiple classes of LRAs in several in vitro models, suggesting that it is compatible with cure approaches utilizing these LRAs. Additionally, rapamycin does not inhibit the early T cell activation (CD69 upregulation) in primary T cells that occurs during protein kinase C (PKC) modulator-mediated HIV latency reversal. Furthermore, in vitro chronically exhausted CAR T cells were found to have a higher frequency of terminally exhausted PD-1+Tim-3+ and CD69+PD-1+ cells when compared to CAR T cells that were cultured under the same conditions in the presence of rapamycin, validating the use of the mTORC1 inhibitor rapamycin to prevent immune exhaustion of CAR T cells. Finally, we found that latently-infected cells that were stimulated to express HIV proteins using a designed, synthetic PKC modulator LRA (SUW133) were efficiently recognized and killed by CAR T cells. Overall, these data demonstrate the compatibility of immune rejuvenation using rapamycin with HIV reservoir depletion using LRAs and CAR T cells. This combination therapy strategy represents a promising approach to more effectively target the latent reservoir in HIV cure approaches.

immunology↗

bioRxiv2025

Succinate Dehydrogenase-Deficient Cancer Cells Have Increased Susceptibility to Ym155 Induced DNA Damage

The hereditary pheochromocytoma and paraganglioma (hPPGL) syndrome is caused by inherited mutations in Succinate Dehydrogenase genes (SDHx). Affected individuals are predisposed to developing pheochromocytomas (Pheo), paragangliomas (PGL), renal cell carcinoma (RCC) and gastrointestinal stromal tumors (GIST). Notably, tumors with succinate dehydrogenase subunit B (SDHB) deficiency demonstrate increased metastatic risk, for which treatments remain palliative. Hence, discovering novel therapeutic avenues to improve the prognosis for SDHB-cancer patients is an urgent need. Here we employed human SDHB-deficient UOK269 RCC cells (SDHB-KO) and isogenic SDHB-reconstituted control cells (SDHB-WT) to discover SDH-dependent mitochondria-directed cytotoxic agents. Given the reduced ATP-generating capacity of SDHB-KO cells, we hypothesized they would be uniquely sensitive to futile cycle induction with mitochondrial ionophores (2,4-Dinitrophenol (2-DNP), BAM15, Niclosamide, Nitazoxanide). Indeed, these compounds exhibited preferential cytotoxicity toward SDHB-KO cells. However, the chemotherapeutic compound Ym155 demonstrated the most potent and dramatic (five-fold) preferential cytotoxicity towards SDHB-KO cells. Importantly, the SDH-dependent cytotoxicity of Ym155 was validated in both primary human pheochromocytoma cells and mouse pheochromocytoma (MPC) cells. Furthermore, because few SDH-deficient cell lines are available, we buttressed our findings in additional relevant cell lines by modeling SDH-deficiency using chemical SDH enzyme inhibition with 3-nitropropionic acid (3-NPA). We observed a persistent cooperativity between SDH-deficiency and Ym155 cytotoxicity across multiple cell lineages and disease models. Mechanistically, Ym155-induced cytotoxicity was independent of its primary target, Survivin. Instead, SDH-deficiency sensitized cells to Ym155-induced DNA damage. Strikingly, the phenotype of SDH-deficient Ym155 sensitivity was recapitulated by inhibition of the histone demethylase KDM4, a downstream consequence of SDH deficiency. Thus, the accumulation of succinate in SDH-deficient tumors inhibits KDM4 activity, impairs DNA repair and yields enhanced susceptibility to Ym155-induced reactive oxygen species (ROS) generation. The identified intrinsic susceptibilities of SDHB-deficient cancers has the potential to be therapeutically leveraged.

cancer biology↗

bioRxiv2025

A Novel Glia-immune humanized mouse model for investigation of HIV CNS infection and neuroinflammation.

Dysregulation in neuroimmune interactions drives pathology in diverse neurological disorders. However, human cell-based in vivo models are limited for clinically relevant mechanistic studies and drug testing. To address this, we developed a novel humanized mouse model integrating all four major types of human glia - astrocytes, oligodendrocyte precursor cells (OPCs), oligodendrocytes, and microglia - in the brain, alongside donor-matched human immune system in peripheral blood and lymphoid tissues. We applied this model to study HIV-associated neurocognitive disorders, which can persist in tissue reservoirs including in the brain despite viral suppression by antiretroviral therapy. These glia-immune humanized mice supported robust HIV-1 replication in the peripheral blood, lymphoid tissues, and the brain, and recapitulated the synapse loss observed in patients. Furthermore, HIV-infected mice exhibited heightened inflammation in both peripheral and brain tissues. Notably, OPCs and oligodendrocytes in HIV-infected brains adopted an immune activated phenotype, upregulating interferon-stimulated genes, highlighting understudied roles of oligodendroglia in HIV infection. RNA-sequencing of human glia identified the upregulation of inflammasome-associated genes and the downregulation of genes involved in transcriptional, epigenetic, and metabolic regulation. Overall, this model provides a powerful in vivo platform to investigate human neuroimmune interactions relevant to diverse neurological disorders, offering critical insights into HIV CNS infection, pathology, and potential therapeutic strategies targeting CNS reservoirs and neuroinflammatory pathways.

immunology↗

bioRxiv2024

Anti-HIV-1 HSPC-based gene therapy with safety kill switch to defend against and attack HIV-1 infection

Hematopoietic stem/progenitor cell (HSPC)-based anti-HIV-1 gene therapy holds promise to provide life-long remission following a single treatment. Here we report a multi-pronged anti-HIV-1 HSPC-based gene therapy designed to defend against and attack HIV-1 infection. We developed a lentiviral vector capable of co-expressing three anti-HIV-1 genes. Two are designed to prevent infection, including a short-hairpin RNA (CCR5sh1005) to knock down HIV-1 co-receptor CCR5 and a membrane anchored HIV-1 fusion inhibitor (C46). The third gene is a CD4-based chimeric antigen receptor (CAR) designed to attack HIV-1 infected cells. Our vector also includes a non-signaling truncated human epidermal growth factor receptor (huEGFRt) which acts as a negative selection-based safety kill switch against transduced cells. Anti-HIV-1 vector-transduced human CD34+ HSPC efficiently reconstituted multi-lineage human hematopoietic cells in humanized bone marrow/liver/thymus (huBLT) mice. HIV-1 viral load was significantly reduced (1-log fold reduction, p <0.001) in transplanted huBLT mice. Anti-huEGFR monoclonal antibody Cetuximab (CTX) administration significantly reduced huEGFRt+ vector-modified cells (>4-fold reduction, p <0.01) in huBLT mice. These results demonstrate that our strategy is highly effective for HIV-1 inhibition, and that CTX-mediated negative selection can deplete anti-HIV-1 vector-modified cells in the event of unwanted adverse effects in huBLT mice.

microbiology↗

bioRxiv2024

Rapamycin Enhances CAR-T Control of HIV Replication and Reservoir Elimination in vivo.

Chimeric Antigen Receptor (CAR) T cell therapy has emerged as a powerful immune therapy for various diseases. Our studies in humanized mice and non-human primates (NHPs) demonstrate that hematopoietic stem cell (HSCs) modified with anti-HIV CAR leads to lifelong engraftment and supply of functional anti-viral CAR-T cells, leading to significantly reduced viral rebound after ART withdrawal. However, T cell exhaustion, driven by chronic immune activation, remains a major challenge for the continuous efficacy of CAR-T therapy, necessitating additional measures to achieve functional cure. We recently showed that in vivo treatment with low dose rapamycin reduced chronic inflammation and improved anti-HIV T cell function in HIV-infected humanized mice. Here, we report that rapamycin significantly improved CAR-T cell function both in vitro and in vivo. In vitro treatment with rapamycin improved CAR-T cell mitochondria respiration and cytotoxicity. In vivo treatment with low-dose rapamycin in HIV-infected, CAR-HSC treated mice reduced chronic inflammation, prevented exhaustion of CAR-T cells and improved CAR-T control of viral replication compared to CAR-HSCs treatment alone. RNAseq analysis of sorted CAR-T cells from humanized mice showed that rapamycin significantly modified the CAR-T cell transcriptome, including the downregulation of multiple check point inhibitors and the upregulation of key genes related to cell survival. We also observed significantly delayed viral rebound after ART withdrawal and diminished HIV reservoir in mice that were treated with rapamycin and CAR-HSCs as compared to CAR-HSCs treatment alone. Taken together, our data indicate that HSCs-based anti-HIV CAR-T combined with rapamycin treatment is a promising approach for treating persistent inflammation and improving immune control of HIV replication.

immunology↗

bioRxiv2023

Structural and Biological Evaluations of a Non-Nucleoside STING Agonist Specific for Human STING-A230 Variants

Previously we identified a non-nucleotide tricyclic agonist BDW568 that activates human STING (stimulator of interferon genes) gene variant containing A230 in a human monocyte cell line (THP-1). STINGA230 alleles, including HAQ and AQ, are less common STING variants in human population. To further characterize the mechanism of BDW568, we obtained the crystal structure of the C-terminal domain of STINGA230 complexed with BDW-OH (active metabolite of BDW568) at 1.95 [A] resolution and found the planar tricyclic structure in BDW-OH dimerizes in the STING binding pocket and mimics the two nucleobases of the endogenous STING ligand 2,3-cGAMP. This binding mode also resembles a known synthetic ligand of human STING, MSA-2, but not another tricyclic mouse STING agonist DMXAA. Structure-activity-relationship (SAR) studies revealed that all three heterocycles in BDW568 and the S-acetate side chain are critical for retaining the compounds activity. BDW568 could robustly activate the STING pathway in human primary peripheral blood mononuclear cells (PBMCs) with STINGA230 genotype from healthy individuals. We also observed BDW568 could robustly activate type I interferon signaling in purified human primary macrophages that were transduced with lentivirus expressing STINGA230, suggesting its potential use to selectively activate genetically engineered macrophages in macrophage-based approaches, such as chimeric antigen receptor (CAR)-macrophage immunotherapies.

pharmacology and toxicology↗

bioRxiv2018

p38α in CD11c+ cells drives sex-specific differences during progression of autoimmune demyelination

Multiple sclerosis (MS) is a chronic autoimmune demyelinating disease with high variability of clinical symptoms. In most cases MS appears as a relapsing-remitting disease course that at a later stage transitions into irreversible progressive decline of neurologic function. The mechanisms underlying MS progression remain poorly understood. Experimental autoimmune encephalomyelitis (EAE) is an animal model of MS. Here we demonstrate that mice that develop mild EAE after immunization with myelin oligodendrocyte glycoprotein 35-55 are prone to undergo clinical progression around 30 days after EAE induction. EAE progression was associated with reduction in CD11c+ microglia and dispersed coalescent parenchymal infiltration. We found sex-dependent differences mediated by p38 signaling, a key regulator of inflammation. Selective reduction of CD11c+ microglia in female mice with CD11c-promoter driven p38 knockout (KO) correlated with increased rate of EAE progression. In protected animals, we found CD11c+ microglia forming contacts with astrocyte processes at the glia limitans and immune cells retained within perivascular spaces. Together, our study provides evidence on the protective role of CD11c+ microglia in controlling CNS immune cell parenchymal infiltration in autoimmune demyelination.

neuroscience↗

bioRxiv2017

Interferon-inducible miR-128 modulates HIV-1 replication by targeting TNPO3 mRNA

The HIV/AIDS pandemic remains an important threat to human health. We have recently demonstrated that a novel microRNA (miR-128) represses retrotransposon (LINE-1 or L1) by a dual mechanism, by directly targeting the coding region of the L1 RNA and by repressing a required nuclear import factor (TNPO1). We have further determined that miR-128 represses the expression of all three isoforms of TNPO proteins (transportins, TNPO1,-2 and TNPO3). Here, we establish that miR-128 also controls HIV-1 replication by repressing TNPO3. TNPO3 is well established to regulate HIV-1 nuclear import and viral replication. Here, we report that the type I interferon inducible miR-128 directly targets two sites in the TNPO3 mRNA, significantly down-regulating TNPO3 mRNA and protein expression levels. Manipulation of miR-128 levels in HIV target cell lines and in primary human CD4 T-cells by over-expression or knockdown showed that modulation of TNPO3 by miR-128 affects HIV-1 replication but not MLV infection. In addition, we found that miR-128 modulation of HIV-1 replication is reduced with TNPO3-independent HIV-1 virus and in cells depleted of CPSF6, suggesting that miR-128-indued TNPO3 repression is partly required for miR-128-induced inhibition of HIV-1 replication. Finally, challenging miR-modulated Jurkat cells or primary CD4 T-cells with wildtype, replication-competent HIV-1 shows that miR-128 significantly delays spreading infection. Thus, we have established a novel role of miR-128 in anti-viral defense in human cells, inhibiting HIV-1 replication partly by targeting TNPO3.

cell biology↗