Biology subjects

Jamal, L.

Publications and source records attributed to Jamal, L..

3 recordsLinked to original sources

bioRxiv2026

Probing the interaction between the WDR41 7CD loop of the C9ORF72 complex and purified PQLC2

The lysosomal cationic amino acid transceptor PQLC2 integrates transport with receptor-like signaling roles by recruiting the C9ORF72/SMCR8/WDR41 (CSW) complex in response to cellular cationic amino acid depletion. CSW recruitment depends on the interaction of PQLC2 with a disordered loop (7CD loop) extending from the WDR41 {beta}-propeller. Defining the molecular basis of this interaction is therefore essential for understanding how PQLC2 connects cellular amino acid availability to downstream signaling. Here, we used site-directed electron paramagnetic resonance (EPR) spectroscopy to characterize the interaction between purified PQLC2 and a synthetic WDR41 7CD loop peptide containing a site-specific nitroxide spin label. Using a consensus mutagenesis strategy, we stabilized detergent-purified PQLC2 and found that it assembles as a homotrimer, similar to other PQ-loop transporters. EPR experiments demonstrated the direct and specific association of the 7CD loop with PQLC2, and highlighted the key role of the the central region of the 7CD loop to establish this interaction via conserved aromatic residues. Spin labels introduced at different positions further provided local structural and dynamic information of the 7CD loop upon PQLC2 binding. The data supports a model in which the central region of the loop is anchored within the cytosolic cavity of PQLC2, whereas the flanking regions, which are dispensable for binding, retain substantial conformational flexibility. Together, we provide a direct biochemical evidence for PQLC2/WDR41 7CD loop recognition, a step forward towards understanding the transceptor mechanism of PQLC2.

biochemistry↗

bioRxiv2023

Anti-Viral and Anti-Inflammatory Therapeutic Effect of RAGE-Ig Protein Against Multiple SARS-CoV-2 Variants of Concern Demonstrated in K18-hACE2 Mouse and Syrian Golden Hamster Models

SignificanceSARS-CoV-2 Variants of Concern (VOCs) continue to evolve and re-emerge with chronic inflammatory long-COVID sequelae necessitating the development of anti-inflammatory therapeutic molecules. Therapeutic effects of the Receptor for Advanced Glycation End products (RAGE) were reported in many inflammatory diseases. However, a therapeutic effect of the RAGE in COVID-19 has not been reported. In the present study, we investigated whether and how the RAGE-Ig fusion protein would have an anti-viral and anti-inflammatory therapeutic effect in the COVID-19 system. MethodsThe protective therapeutic effect of RAGE-Ig was determined in vitro in K18-hACE2 transgenic mice and Syrian golden hamsters infected with six various VOCs of SARS-CoV-2. The underlying anti-viral mechanism of RAGE-Ig was determined in vitro in SARS-CoV-2-infected human lung epithelial cells (BEAS-2B). ResultsFollowing treatment of K18-hACE2 mice and hamsters infected with various SARS-CoV-2 VOCs with RAGE-Ig, we demonstrated: (i) significant dose-dependent protection (i.e. greater survival, less weight loss, lower virus replication in the lungs); (ii) a reduction of inflammatory macrophages (F4/80+/Ly6C+) and neutrophils (CD11b+/Ly6G+) infiltrating the infected lungs; (iii) a RAGE-Ig dose-dependent increase in the expression of type I interferons (IFN-, and IFN-{beta}) and type III interferon (IFN{lambda}2) and a decrease in the inflammatory cytokines (IL-6 and IL-8) in SARS-CoV-2-infected human lung epithelial cells; and (iv) a dose-dependent decrease in the expression of CD64 (FcgR1) on monocytes and lung epithelial cells from symptomatic COVID-19 patients. ConclusionOur pre-clinical findings revealed type I and III interferons-mediated anti-viral and anti-inflammatory therapeutic effects of RAGE-Ig protein against COVID-19 caused by multiple SARS-CoV-2 VOCs.

immunology↗

bioRxiv2021

Antiviral CD19+CD27+ Memory B Cells Are Associated with Protection from Recurrent Asymptomatic Ocular Herpes Infection

Reactivation of herpes simplex virus 1 (HSV-1) from latently infected neurons of the trigeminal ganglia (TG) leads to blinding recurrent herpetic disease in symptomatic (SYMP) individuals. Although the role of T cells in herpes immunity seen in asymptomatic (ASYMP) individuals is heavily explored, the role of B cells is less investigated. In the present study, we evaluated whether B cells are associated with protective immunity against recurrent ocular herpes. The frequencies of circulating HSV-specific memory B cells and of memory follicular helper T cells (CD4+ Tfh cells), that help B cells produce antibodies, were compared between HSV-1 infected SYMP and ASYMP individuals. The levels of IgG/IgA and neutralizing antibodies were compared in SYMP and ASYMP individuals. We found that: (i) the ASYMP individuals had increased frequencies of HSV-specific CD19+CD27+ memory B cells; and (ii) high frequencies of HSV-specific switched IgG+CD19+CD27+ memory B cells detected in ASYMP individuals were directly proportional to high frequencies of CD45R0+CXCR5+CD4+ memory Tfh cells. However, no differences were detected in the level of HSV-specific IgG/IgA antibodies in SYMP and ASYMP individuals. Using the UV-B-induced HSV-1 reactivation mouse model, we found increased frequencies of HSV-specific antibody-secreting plasma HSV-1 gD+CD138+ B cells within the TG and circulation of ASYMP mice compared to SYMP mice. In contrast, no significant differences in the frequencies of B cells were found in the cornea, spleen, and bone-marrow. Our findings suggest that circulating antibody-producing HSV-specific memory B cells recruited locally to the TG may contribute to protection from symptomatic recurrent ocular herpes. IMPORTANCEReactivation of herpes simplex virus 1 (HSV-1) from latently infected neurons of the trigeminal ganglia (TG) leads to blinding recurrent herpetic disease in symptomatic (SYMP) individuals. Although the role of T cells in herpes immunity against blinding recurrent herpetic disease is heavily explored, the role of B cells is less investigated. In the present study, we found that in both asymptomatic (ASYMP) individuals and ASYMP mice there was increased frequencies of HSV-specific memory B cells that were directly proportional to high frequencies of memory Tfh cells. Moreover, following UV-B induce reactivation, we found increased frequencies of HSV-specific antibody-secreting plasma B cells within the TG and circulation of ASYMP mice, compared to SYMP mice. Our findings suggest that circulating antibody-producing HSV-specific memory B cells recruited locally to the TG may contribute to protection from recurrent ocular herpes.

immunology↗