Biology subjects

Khalfi, S.

Publications and source records attributed to Khalfi, S..

4 recordsLinked to original sources

bioRxiv2026

ALDH Activity in Monocytes is Associated with Subclinical Coronary Atherosclerosis in Treated People with HIV-1

People living with HIV-1 (PWH) receiving antiretroviral therapy (ART) exhibit an increased cardiovascular disease (CVD) risk. Coronary atherosclerotic plaque formation is linked to chronic immune activation, a process fueled in PWH by additional mechanisms likely including residual HIV-1 production and microbial translocation from the gut during ART. Our previous studies demonstrated that aldehyde dehydrogenase (ALDH), an enzyme converting vitamin A into retinoic acid (RA), is upregulated in myeloid cells upon exposure to viral/bacterial/fungal products and that RA promotes HIV-1 production. To explore the link between ALDH/RA pathway and CVD risk, we used PBMC/plasma from ART-treated PWH (PWH+ART; n=51) and people without HIV-1 (Pw/oH; n=63) from the Canadian HIV/Aging Cohort Study, with/without subclinical coronary atherosclerosis, measured by coronary computed tomography angiography. ALDH expression was analyzed by flow cytometry on monocyte subsets, dendritic cells, and CD4+ T-cells. Unsupervised t-SNE-guided FlowSOM analysis associated top ALDH activity with a monocyte phenotype. The frequency of ALDH+ monocytes and plasma levels of RA and retinol binding protein 4 were increased in PWH+ART versus Pw/oH, with the highest RA levels coinciding with detectable plasma levels of soluble HIV-1 gp120. Multivariate regression models linked ALDH activity in monocytes to subclinical coronary atherosclerosis (i.e., total plaque volume, low attenuated plaque volume, coronary artery calcification score) presence/burden in PWH+ART, independently of Framingham risk score. Finally, ALDH+ monocyte frequency and RA levels positively correlated with pericoronary fat attenuation index, an emerging CVD predictor. Thus, ALDH/RA pathway may represent a new marker of metabolic/immune dysfunction contributing to CVD risk in ART-treated PWH.

immunology↗

bioRxiv2026

REV-ERBα/β Targeting Transcriptionally Reprograms HIV-Infected CD4+ T-Cells for Increased Viral Reactivation but Limited Virion Spread

The circadian clock repressors REV-ERB/{beta} control rhythmic gene expression and inhibit HIV-1 transcription. Whether REV-ERB/{beta} modulate the HIV-1 replication cycle beyond transcription remains unknown. Here, we demonstrate that memory CD4+ T-cells predominantly express the REV-ERB{beta} isoform ex vivo and that T-cell receptor (TCR) triggering downregulates both REV-ERB/{beta} expression, with levels of REV-ERB/{beta} mRNA being lower in ART-treated people with HIV (PWH) receiving antiretroviral therapy (ART) compared to people without HIV (PWoH) before/after TCR triggering. In single-round infection, the REV-ERB/{beta} antagonist SR8278 facilitated HIV-1 reverse transcription, integration, and intracellular HIV-p24 expression, but limited virion release. Moreover, SR8278 downregulated CCR5 mRNA expression, inhibited R5-tropic HIV-1 replication in vitro, and limited viral outgrowth in CD4+ T-cells from ART-treated PWH. Finally, genome-wide RNA-sequencing and functional validations revealed HIV-1 restriction/dependency factors that represent novel putative REV-ERB/{beta} targets. Thus, pharmacological inhibition of REV-ERB/{beta} uniquely combines a latency reversal activity with the inhibition of progeny virion spread.

immunology↗

bioRxiv2026

Identification of the cellular transcription factor KLF16 as a novel repressive epigenetic repressor of HIV-1 transcription

Despite antiretroviral therapy, human immunodeficiency virus type 1 (HIV-1) persists in latently-infected cells through epigenetic and transcriptional mechanisms. Latency-reversing agents have failed clinically, partly due to incomplete understanding of HIV-1 latency reversal. Here, using DNA-affinity capture and mass spectrometry on the HIV-1 5 long terminal repeat (5LTR) enhancer-core promoter, we identify KLF16 (Kruppel-like Factor 16) as a novel regulator of HIV-1 gene expression. KLF16 binds to the HIV-1 5LTR in vivo at Sp1 binding sites, and KLF16 depletion reactivates latent HIV-1 in T-lymphoid and monocytic cell models. Mechanistically, KLF16 represses HIV-1 transcription by competing with Sp1 for promoter binding and by recruiting the Sin3A/HDAC1 and HP1/Suv39H1 repressive epigenetic complexes. KLF16 is also upregulated in CD4+ T cells from ART-treated people with HIV-1 upon T-cell activation. Additionally, All-Trans retinoic acid (ATRA) reactivates latent HIV-1 in myeloid cells, partly by downregulating KLF16. These findings establish KLF16 as a novel transcriptional repressor of HIV-1, identifying it as a potential promising therapeutic target for cure strategies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/722432v1_ufig1.gif" ALT="Figure 1"> View larger version (39K): org.highwire.dtl.DTLVardef@1611026org.highwire.dtl.DTLVardef@16b5eaforg.highwire.dtl.DTLVardef@153b11org.highwire.dtl.DTLVardef@1d90330_HPS_FORMAT_FIGEXP M_FIG C_FIG

microbiology↗

bioRxiv2023

Mammalian cells-based platforms for the generation of SARS-CoV-2 virus-like particles

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of COVID-19. Though many COVID-19 vaccines have been developed, most of them are delivered via intramuscular injection and thus confer relatively weak mucosal immunity against the natural infection. Virus-Like Particles (VLPs) are self-assembled nanostructures composed of key viral structural proteins, that mimic the wild-type virus structure but are non-infectious and non-replicating due to the lack of viral genetic material. In this study, we efficiently generated SARS-CoV-2 VLPs by co-expressing the four SARS-CoV-2 structural proteins, specifically the membrane (M), small envelope (E), spike (S) and nucleocapsid (N) proteins. We show that these proteins are essential and sufficient for the efficient formation and release of SARS-CoV-2 VLPs. Moreover, we used lentiviral vectors to generate human cell lines that stably produce VLPs. Because VLPs can bind to the virus natural receptors, hence leading to entry into cells and viral antigen presentation, this platform could be used to develop novel vaccine candidates that are delivered intranasally. HighlightsO_LIIdentification of protein requirements for SARS-CoV-2 VLP production by transient transfection C_LIO_LILentiviral transduction to create cells stably producing SARS-CoV-2 VLPs C_LIO_LIIsolation of cell clones for the production of SARS-CoV-2 VLPs C_LIO_LINew putative platforms for vaccine development C_LI

microbiology↗