Biology subjects

Parveen, S.

Publications and source records attributed to Parveen, S..

At least 19 recordsLinked to original sources

bioRxiv2026

Lipid composition-driven sorting of ABHD5 between monolayer and bilayer surfaces

Lipid droplets (LDs) are ubiquitous organelles that store neutral lipids and serve as central regulators of lipid homeostasis. Their structure includes a hydrophobic core of triacylglycerols and sterol esters surrounded by a phospholipid monolayer. This organization creates biophysical properties that guide selective protein recruitment. Among LD-associated proteins, /{beta}-hydrolase domain-containing protein 5 (ABHD5, also known as CGI-58) is a key regulator of lipolysis and broader lipid metabolism, yet the mechanisms guiding its distribution between endoplasmic reticulum (ER) bilayers and LD monolayers remain poorly understood. Because proper membrane association of ABHD5 is essential for activating PNPLA family lipases, identifying the determinants of its membrane selectivity is critical for understanding LD function in health and disease. In this study, we examined ABHD5 binding and sorting behavior using model membrane systems composed of giant unilamellar vesicles (GUVs) and droplet-embedded vesicles (DEVs) incorporating defined phospholipid and neutral lipid compositions. By integrating experimental assays with computational modeling, we quantified how ABHD5 partitions between bilayer membranes mimicking the ER and monolayer surfaces mimicking LDs. Systematic variation of membrane composition and physical properties allowed us to assess how packing defects and neutral lipid content shape ABHD5 localization. Our findings reveal the biophysical features that favor ABHD5 association with LD-like monolayers and provide new mechanistic insight into how cells target regulatory proteins to distinct membrane environments to control lipid metabolism.

biophysics↗

bioRxiv2026

Transforming off-the-shelf personal glucose meter into a sustainable and decentralized label-free nucleic acid and NAAT detection platform

In todays world, point-of-care nucleic acid detection still remains extensively constrained and limited by the heavy dependence on centralized urban instrumentation facilities and complex assay workflows. Here, we elucidate a glucometer-based analytical platform that enables label-free detection of nucleic acids and the nucleic acid amplification products through a simple redox-mediated mechanism. The approach leverages the potassium ferricyanide (K3[Fe(CN)6])/ potassium ferrocyanide (K4[Fe(CN)6]), redox system, which is intrinsic to commercial glucometers, complementing with interactions between methylene blue (MB) and nucleic acids. These interactions transduce concentration differences in nucleic acids into quantifiable electrochemical signal readouts. Distinct varied signal outputs are observed between single-stranded and double-stranded DNA, enabling the direct detection as well as integration with nucleic acid amplification tests (NAATs), including polymerase chain reaction, rolling circle amplification, and loop-mediated isothermal amplification. Optimization of reaction parameters and conditions leads to enhancement of the overall signal discrimination and sensitivity across various assay formats. This innovation repurposes widely available off-the-shelf glucometers as a low-cost, portable nucleic acid detectors, thus eliminating the need for any specialized instrumentation. Our results enumerate and establish a generalized and scalable strategy for nucleic acid sensing. The platform thus supports sustainable and environmentally responsible point-of-care testing, thereby enabling improved accessibility and public health monitoring at resource-limited and remote settings.

biochemistry↗

bioRxiv2026

EZH2 Inhibition Reshapes 3D Chromatin Architecture to Induce Immunogenic Phenotype in Small Cell Lung Cancer

BackgroundThe histone methyltransferase EZH2, enzymatic core of the trimeric polycomb repressive complex 2 (PRC2), has been shown to promote small cell lung cancer (SCLC) survival through epigenetic silencing of multiple targets including Class I MHC molecules (HLA-A/B) and DNA repair factors (SLFN11). Treatment of SCLC cells with EZH2 inhibitors in vitro can reactivate expression of these genes and result in therapeutic response to immune checkpoint inhibition (ICI) and chemotherapy. Here, we investigate the impact of EZH1/2 dual inhibition on 3D chromatin structure and its relationship to transcriptional regulation in neuroendocrine (NE) SCLC. ResultsEmploying Micro-C, a micrococcal nuclease-based 3D genome mapping technique, we show that EZH1/2 inhibition with Valemetostat induced significant changes at multiple genome organizational levels (compartment, topological associated domain, and chromatin loop) without incurring cell death in NE SCLC. Alterations in 3D genome permissive for transcriptional activation were correlated with increased chromatin accessibility (ATAC-sequencing) and expression of target genes (transcriptome profiling). Known transcription factor motif discovery revealed enrichment of non-NE motifs (e.g., REST) in regions with gained chromatin accessibility in Valemetostat-treated cells, consistent with results from gene set enrichment analysis demonstrating NE to non-neuroendocrine lineage shift. Notably, EZH1/2 inhibition reactivated Class I MHC expression by facilitating enhancer-promoter looping. ConclusionOur results demonstrate that repression of a subset of EZH2 targets including Class I MHC genes is affected through modulation of 3D genome structure to the level of chromatin looping and further support clinical investigation of EZH2 inhibition in boosting therapeutic efficacy of ICI in SCLC patients.

genomics↗

bioRxiv2025

Mutation bias is a key predictor of adaptation rate

A growing body of work indicates that mutation bias -- whereby some types of mutations occur more often than others -- can influence the genetic basis of adaptation and the distribution of fitness effects of new mutations, with potentially important evolutionary consequences. Specifically, reversing an ancestral mutation bias (e.g., in Escherichia coli, shifting from a transition-biased to a transversion-biased mutation spectrum) enhances access to under-sampled variants, increasing the supply of beneficial mutations. However, the effect of mutation bias relative to other factors influencing adaptation remains unclear. By experimentally evolving wild type and mutator E. coli strains in different growth media, we show that mutation bias reversal facilitates early adaptation, altering the genetic basis of adaptation and the type of mutations accumulated under selection. Together, mutation bias, mutation rate, and initial fitness correctly predicted relative adaptation rates for any pair of strains. Our results highlight multiple ways in which mutational processes can shape genetic and phenotypic outcomes of adaptation.

evolutionary biology↗

bioRxiv2025

Evaluating horseradish peroxidase-mimic DNAzyme transducer for glucometer readout: roles of various components and their optimization

The Development of decentralized disease detection elements is integral towards ensuring democratized access to healthcare. Personal glucometers, thanks to their low cost, ease of usage, and universal availability, are increasingly being identified as a central tenet of democratized disease detection. Towards this objective, it will first be critical to establish whether glucometers can be integrated with established molecular diagnosis workflows such as enzyme-linked absorbent assay (ELISA) or its analogous techniques such as enzyme-linked aptasorbent assays (ELASA). In ELISA or its analogous assays, horseradish peroxidase (HRP) or its mimics, such as hemin DNAzyme conjugated to biorecognition elements (e.g., antibody or aptamers), serve as the signal transducers. These transducers generate colorimetric or electrochemical signals measurable in centralized instruments such as ELISA readers or potentiostats. To become compatible with ELISA readouts in decentralized settings, the glucometers should therefore be able to quantify the activity of HRP mimics such as hemin DNAzyme. The current work thus explores the possibility of the use of glucometers as a general readout instrument for hemin DNAzyme transducer activity involving potassium ferrocyanide as a novel redox substrate. Using both absorbance and glucometer readout, we systematically investigated the role of buffer, pH, redox mediator, and H2O2 in achieving optimal readout conditions. It also probed the prospective DNAzyme operational range under these assay conditions. In addition, transferability of optimized assay parameters in other commercial glucometer brands, as well as preliminary suitability in HRP enzyme, was explored. Altogether, our study explores the possibility of using DNAzymes as transducers for glucometers as a democratized alternative to ELISA readers, multimode readers, or potentiostats towards equitable access to disease diagnosis.

biochemistry↗

bioRxiv2025

Multiplexed Molecularly-Specific SWCNT Cytokine Sensing is Enabled and Enhanced by Amine-Functionalized DNA Aqueous Two-Phase Extraction

Single-walled carbon nanotubes (SWCNT) are versatile building blocks for optical sensors. Their carbon lattice structure, denoted by chiral (n,m) indices, determines the wavelength of their near infrared fluorescence emission. Commercially available SWCNT are polydisperse, containing many (n,m) species with overlapping fluorescence peaks, leading to spectral congestion. Aqueous two-phase extraction (ATPE) has emerged as a valuable tool to sort SWCNT according to their chiral structure and promises improved nanosensor performance as well as unique opportunities for multiplexing. Previous applications of ATPE have enabled ratiometric sensors, but simultaneous detection of multiple analytes using distinct SWCNT chiralities has yet to be realized. This hurdle is largely due to the contrasting surface chemistries needed for ATPE sorting and those needed for biosensing applications. In this work, we introduce a method for purifying multiple chiralities of SWCNT which can be functionalized with molecularly specific antibodies to create a multiplexed sensor platform. We utilize aminated DNA (DNA-NH2), which serves as both a conduit for ATPE sorting and an intermediate linker for later antibody conjugation, to realize this goal. We demonstrate that chemically modified DNA enables ATPE sorting, supporting the broad future utility of the technique. We further show that chirality-sorted SWCNT-DNA-NH2 serve as excellent base constructs for antibody conjugation, forming highly specific sensors with enhanced optical properties (compared to unsorted SWCNT sensors). Importantly, one batch of monochiral base constructs can be functionalized with different antibodies towards different biological applications. Finally, we show that we can sort and functionalize two separate SWCNT chiralities and combine them together to create a multiplexed sensor platform where each peak responds distinctly to its target. There are vast opportunities for expansion of this work through the use of alternative DNA sequences to enable sorting, various SWCNT chiralities, and virtually any commercially available antibody for molecular recognition.

bioengineering↗

bioRxiv2025

Unraveling the Molecular Mechanisms of ABHD5 Membrane Targeting

ABHD5 is a master regulator of PNPLA family lipases, particularly PNPLA2 (ATGL), the rate-limiting triglyceride (TAG) hydrolase in metabolic tissues. Despite its central role in lipid metabolism, the molecular basis by which ABHD5 recognizes membranes and regulates enzymatic activity remains poorly understood. Here, we report an integrated computational-experimental study revealing how the /{beta}-hydrolase domain-containing protein 5 (ABHD5) dynamically engages lipid droplet (LD) and endoplasmic reticulum membranes to control lipolytic activation. Using multiscale molecular dynamics simulations, hydrogen-deuterium exchange mass spectrometry, and site-directed mutagenesis, we uncover a sequential dual-site membrane recognition mechanism, where the N-terminus provides initial anchoring and a lid helix within the insertion segment forms a crucial secondary contact. Membrane binding triggers a dramatic conformational switch in this lid, expanding the pseudosubstrate pocket and transforming ABHD5 into an active and membrane-localized regulator. This structural transition is coupled to membrane remodeling, inducing localized curvature and forming a triacylglycerol-enriched nanodomain beneath the ABHD5 pseudosubstrate pocket. This bidirectional interaction between ABHD5 and the membrane provides a persuasive mechanism for interfacial activation. Our findings establish new principles for how LD-binding proteins achieve functional specificity through membrane-dependent regulation, offering novel molecular targets for interventions in metabolic diseases. TeaserA key protein controls fat breakdown by changing shape when it binds membranes and reshapes local fat droplets.

biophysics↗

bioRxiv2024

An anomalous 3'-terminal phosphorothioated mismatch bypass activity and its application as a binary molecular switch

Phosphorothioated (PST) oligonucleotides are increasingly being used in RNA silencing, antisense, and biosensing applications. However, the possibilities and consequences of their desultory interactions with other possible nucleic acids and DNA polymerases inside the cell remain inadequately characterized. In this study, we report the discovery of an unusual terminal mismatch bypass activity involving 3'-PST containing DNA primers and certain strand displacement DNA polymerases. Using rolling circle DNA amplification, we have identified that strand displacement DNA polymerases such as phi29 and BST large fragment (LF) can bypass 3'-terminal PST mismatches upto 1 - 20 nt length. Next, we explore the length and sequence dependence of this unusual attribute, incubation in near-ambient and 60 - 65{degrees}C temperatures, and measures to blockade or modulate this mismatch bypass activity to create a binary fully nucleic acid-based and non-photocontrolled molecular switch (the first of its kind). After proposing possible underlying mechanisms for this activity, we discuss its potential consequences and applications.

biochemistry↗

bioRxiv2024

Mutation bias alters the distribution of fitness effects of mutations

Mutation bias is an important factor determining the diversity of genetic variants available for selection. As adaptation proceeds and some beneficial mutations are fixed, new beneficial mutations become rare, limiting further adaptation. The depletion of beneficial mutations is especially stark within the mutational class favoured by the existing mutation bias. Recent theoretical work predicts that this problem may be alleviated by a change in the direction of mutation bias (i.e., a bias reversal). If populations sample previously underexplored types of mutations, the distribution of fitness effects (DFE) of mutations should shift towards more beneficial mutations. Here, we test this prediction using Escherichia coli, which has a transition mutation bias, with [~]54% single-nucleotide mutations being transitions compared to the unbiased expectation of [~]33% transitions. We generated mutant strains with a wide range of mutation biases, from 97% transitions to 98% transversions, either reinforcing or reversing the wild type transition bias. Quantifying DFEs of [~]100 single mutations obtained from mutation accumulation experiments for each strain, we find strong support for the theoretical prediction. Strains that oppose the ancestral bias (i.e., with a strong transversion bias) have DFEs with the highest proportion of beneficial mutations, whereas strains that exacerbate the ancestral transition bias have up to 10-fold fewer beneficial mutations. Such dramatic differences in the DFE should drive large variation in the rate and outcome of adaptation, suggesting an important and generalized evolutionary role for mutation bias shifts.

evolutionary biology↗

bioRxiv2023

Bacterial pore-forming toxin pneumolysin drives pathogenicity through shed toxin-loaded host extracellular vesicles

Streptococcus pneumoniae is a global priority respiratory pathogen that kills over a million people annually and produces the pore-forming cytotoxin, pneumolysin (PLY). Host cells expel membrane assembled toxin by shedding microvesicles, but the composition and pathophysiological sequelae of the toxin-induced host extracellular vesicles (EVs) are unknown. Here, we found that EVs shed from PLY-challenged monocytes (PLY-EVs) harbor membrane-bound toxin that induced cytotoxicity upon fusion with recipient cells. EVs from human monocytes challenged with recombinant PLY as well as PLY-expressing pneumococcal strains, but not the isogenic PLY mutant, primed dendritic cells and evoked higher pro-inflammatory cytokines upon infection. Proteomic analysis revealed that PLY-EVs are enriched for key antimicrobial and inflammatory host proteins such as IFI16, NLRC4, PTX3 and MMP9. In vivo, zebrafish and mice administered with PLY-EVs showed mortality, pericardial edema, tissue damage and inflammation. Our findings show that host EVs bearing the cytotoxin PLY constitute a previously unexplored mechanism of pneumococcal pathogenesis.

microbiology↗

bioRxiv2023

Epigenetic mediated functional reprogramming of immune cells leads to HBsAg seroconversion in Hepatitis B Virus Reactivation patients

BackgroundHepatitis B virus (HBV) modulates epigenetic landscape by epigenetic regulators. HBsAg seroconversion is possible with immune activation, therefore we aimed to investigate epigenetic modulation in HBV reactivation (rHBV) for viral clearance and seroconversion. MethodsSixteen retrospectively collected rHBV patients [Seroconverters (SC, n=7, HBsAg loss and anti-HBs>10 IU/ml), non- seroconverters (NSC, n=9)], chronic hepatitis B treatment naive (nCHBV, n=7) patients and healthy controls (HC, n=7) were included in this study. Genome methylation, gene expression, plasma-cytokines, and immune cell profiling was analysed by Reduced Representation Bisulfite Sequencing (RRBS), QRT-PCR, multiplex-cytokine-bead array and flow-cytometry. ResultsrHBV patients having high HBV DNA and ALT showed epigenetic remodellers; KDM2B, NCOR2 and GATA6, immune and metabolic genes; TGF-{beta}, IL-6, IRF8, RPTOR, HK3 significantly (p<0.05) hypomethylated at specific CpG islands compared to nCHBV. TOX was hypomethylated in nCHBV suggesting immune-exhaustion. At-baseline, seroconverters showed hypomethylation of KDM2B, COX19, IRF8, TLR5 and hypermethylation of LAG3 compared to non-seroconverters. Further, in seroconverters at week-24, IL17RA, IFN-{gamma}, TGF-{beta}, and STAT5B (p<0.05) were additionally hypomethylated at specific CpG islands suggesting immune activation. Cytokine-bead analysis revealed increased IL-6 (p=0.009) and decreased LAG3 plasma levels (p=0.01) also imply on significantly differentiated HBV specific CD8, Tfh and Th1/17 cells in seroconverters at baseline and week-24. However, both nCHBV and non-seroconverters had consistent hypomethylation of LAG3 and TOX, which leads to immune exhaustion. ConclusionIn rHBV, seroconversion is driven by position specific CpG islands methylation in epigenetic remodellers, immune and metabolic genes. Immune metabolic reprograming is reflected by Th1/17 differentiation, extensive interleukin production for HBsAg seroconversion. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=116 SRC="FIGDIR/small/554133v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@48e206org.highwire.dtl.DTLVardef@ef0fa7org.highwire.dtl.DTLVardef@ecb710org.highwire.dtl.DTLVardef@e6b34e_HPS_FORMAT_FIGEXP M_FIG C_FIG Lay summaryEpigenetic landscape in nCHBV depicts exhaustion and immune dysfunction. Out of many hypermethylated CpG islands of nCHBV, few become hypomethylated in rHBV and drives immune and metabolic reprogramming. This study provides insights into the cellular and molecular basis of epigenomic programs that regulate the differentiation and activation of immune cells leading to viral clearance and seroconversion. Targeting epigenetic mechanism could be promising strategy for the treatment of nCHBV and non-seroconverters.

immunology↗

bioRxiv2023

Methods for making and observing model lipid droplets

The mechanisms by which the lipid droplet (LD) membrane is remodeled in concert with the activation of lipolysis incorporate a complex interplay of proteins, phospholipids, and neutral lipids. Model LDs (mLDs) provide an isolated, purified system for testing the mechanisms by which the droplet composition, size, shape, and tension affects triglyceride metabolism. Described here are methods of making and testing mLDs ranging from 0.1 to 40 {micro}m diameter with known composition. Methods are described for imaging mLDs with high-resolution microscopy during buffer exchanges for the measurement of membrane binding, diffusion, and tension via fluorescence correlation spectroscopy (FCS), fluorescence recovery after photobleaching (FRAP), fluorescence lifetime imaging microscopy (FLIM), atomic force microscopy (AFM), pendant droplet tensiometry, and imaging flow cytometry. These complementary, cross-validating methods of measuring LD membrane behavior reveal the interplay of biophysical processes in triglyceride metabolism.

biophysics↗

bioRxiv2023

Glutamine metabolism inhibition has dual immunomodulatory and antibacterial activities against Mycobacterium tuberculosis

As one of the most successful human pathogens, Mycobacterium tuberculosis (Mtb) has evolved a diverse array of determinants to subvert host immunity and alter host metabolic patterns. However, the mechanisms of pathogen interference with host metabolism remain poorly understood. Here we show that a novel glutamine metabolism antagonist, JHU083, inhibits Mtb proliferation in vitro and in vivo. JHU083-treated mice exhibit weight gain, improved survival, a 2.5 log lower lung bacillary burden at 35 days post-infection, and reduced lung pathology. JHU083 treatment also initiates earlier T-cell recruitment, increased proinflammatory myeloid cell infiltration, and a reduced frequency of immunosuppressive myeloid cells when compared to uninfected and rifampin-treated controls. Metabolomics analysis of lungs from JHU083-treated Mtb-infected mice revealed reduced glutamine levels, citrulline accumulation suggesting elevated NOS activity, and lowered levels of quinolinic acid which is derived from the immunosuppressive metabolite kynurenine. When tested in an immunocompromised mouse model of Mtb infection, JHU083 lost its therapeutic efficacy suggesting the drugs host-directed effects are likely to be predominant. Collectively, these data reveal that JHU083-mediated glutamine metabolism inhibition results in dual antibacterial and host-directed activity against tuberculosis.

microbiology↗

bioRxiv2022

Characterization of Plasmodium falciparum RAP domain proteins-RAP291 and RAP070, and their association with ribosomal RNAs

Plasmodium genomes encode multiple RAP (RNA-binding domain abundant in Apicomplexan) domain proteins that contain a conserved module of 56 to 73 amino acids. Here, we characterized two of the P. falciparum RAP domain proteins; PfRAP291 & PfRAP070, for their expression and role at asexual blood stages. RNA binding assays and high-throughput CLIP-seq analysis showed that these proteins mainly bind ribosome associated RNAs. Blue-native PAGE and protein-protein interaction studies suggested association of these proteins with MSP-1 complex. Anti-PfRAP291 and anti-PfRAP070 antibodies showed moderate inhibitions in in-vitro merozoite invasion assays. Together, these results suggest multiple roles of these proteins; PfRAP291 and PfRAP070, in merozoite invasion and in ribosome regulation during asexual stages of the parasite.

microbiology↗

bioRxiv2021

Regulation of eIF2α Phosphorylation by MAPKs Influences Polysome Stability and Protein Translation

Regulation of protein translation occurs primarily at the level of initiation and is mediated by multiple signaling pathways, majorly mechanistic target of rapamycin complex 1 (mTORC1), mitogen-activated protein kinases (MAPKs), and the eukaryotic translation initiation factor eIF2. While mTORC1 and eIF2 influence the polysome stability, MAPKs influence the phosphorylation of the cap-binding protein eIF4E and are known to influence translation of only a small set of mRNAs. Here, we demonstrate that p38 MAPK and ERK1/2 regulate translation through integrated stress response (ISR) pathways. Dual inhibition (dual-Mi) of p38 MAPK and ERK1/2 caused substantial phosphorylation of eIF2 in a synergistic manner, resulting in near-absolute collapse of polysomes. This regulation was independent of Mnk1/2, a well-studied mediator of translation regulation by the MAPKs. Dual-Mi-induced polysome dissociation was far more striking than that caused by sodium arsenite, a strong inducer of ISR. Interestingly, induction of ISR caused increased p38 phosphorylation, and its inhibition resulted in stronger polysome dissociation, indicating the importance of p38 in the translation activities. Thus, our studies demonstrate a major, unidentified role for ERK1/2 and more particularly p38 MAPK in the maintenance of homeostasis of polysome association and translation activities.

biochemistry↗

bioRxiv2021

Involvement of translocon complex in hemoglobin import from infected erythrocyte cytoplasm into the Plasmodium parasite

Haemoglobin degradation is crucial for the growth and survival of Plasmodium falciparum in human erythrocytes. Although the process of Hb degradation has been studied in great detail, the mechanisms of Hb uptake remain ambiguous to date. Here, we characterized Heme Detoxification Protein (PfHDP), a protein localized in the parasitophorous vacuole, parasite food vacuole and infected erythrocyte cytosol for its role in Hb uptake. Immunoprecipitation of PfHDP-GFP fusion protein from a transgenic line using anti-GFP antibody and of Plasmodium parasite extract using anti-human Hb antibodies respectively, showed the association of PfHDP/Hb with each other as well as with the members of PTEX translocon complex. Some of these associations such as PfHDP/Hb and PfHDP/Pfexp-2 interactions were confirmed by in vitro protein-protein interaction tools. To know the roles of PfHDP and translocon complex in Hb import into the parasites, we next studied the Hb uptake by the parasite in PfHDP knock-down line using the GlmS ribozyme strategy. PfHDP knock-down significantly reduced the Hb uptake in these parasites in comparison to the wild type parasites. Further, the transient knock-down of one of the members of the translocon complex; PfHSP101 showed considerable reduction in Hb uptake. Morphological analysis of PfHDP-HA-GlmS transgenic parasites in the presence of GlcN showed food vacuole abnormalities and parasite stress, thereby causing a growth defect in the development of these parasites. Together, we implicate the translocon complex in the trafficking of PfHDP/Hb complex in the parasite and suggest a role for PfHDP in the uptake of Hb and parasite development. The study thus reveals new insights into the function of PfHDP, making it an extremely important target for developing new antimalarials.

molecular biology↗

bioRxiv2020

Effective host-directed therapy for tuberculosis by targeted depletion of myeloid-derived suppressor cells using a diphtheria toxin-based fusion protein

Myeloid-derived suppressor cells (MDSCs) are present in elevated numbers in TB patients and have been found to be permissive for Mycobacterium tuberculosis (Mtb) proliferation. To determine whether depletion of MDSCs may improve host control of TB, we used a novel diphtheria toxin-based fusion protein known as DABIL-4 that targets and depletes IL-4-receptor positive cells. We show that DABIL-4 depletes both PMN-MDSCs and M-MDSC in the mouse TB model, and that it reduces the lung bacillary burden of Mtb. These results indicate that MDSC-depleting therapies targeting the IL4 receptor are beneficial in TB and offer an avenue towards host-directed TB therapy.

microbiology↗

bioRxiv2020

IL-4 receptor targeting as an effective immunotherapy against triple-negative breast cancer

In many solid tumors including triple-negative breast cancer (TNBC), IL-4 receptor (IL-4R) upregulation has been shown to promote cancer cell proliferation, apoptotic resistance, metastatic potential and a Th2 response in the tumor microenvironment (TME). Immunosuppressive cells in the TME including myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) also express the IL4-R. We hypothesized that selective depletion of IL4-R bearing cells in TNBC may have dual cytotoxic and immunotherapeutic benefit. To selectively target IL-4R+ cells, we genetically constructed, expressed and purified DABIL-4, a fusion protein toxin consisting of the catalytic and translocation domains of diphtheria toxin fused to murine IL-4. We found that DABIL-4 has potent and specific cytotoxic activity against TNBC cells in vitro. In murine TNBC models, DABIL-4 significantly reduced tumor growth, splenomegaly and lung metastases, and this was associated with reductions in MDSC, TAM and regulatory T-cells (Tregs) populations with a concomitant increase in the proportion of IFN{gamma}+ CD8 T-cells. The anti-tumor activity of DABIL-4 was absent in IL-4R KO mice directly implicating IL-4R directed killing as the mechanism of anti-tumor activity. Moreover, NanoString analysis of DABIL-4 treated TNBC tumors revealed marked decline in mRNA transcripts that promote tumorigenesis and metastasis. Our findings demonstrate that DABIL-4 is a potent targeted antitumor agent which depletes both IL-4R bearing tumor cells as well as immunosuppressive cell populations in the TME. STATEMENT OF SIGNIFICANCEIn solid tumors like breast cancer, Interleukin-4 receptor (IL-4R) expression in the tumor microenvironment aids tumor growth and metastasis. IL-4R expression upon host immune cells further dampens antitumor immunity. In this study, we have genetically constructed a fusion protein toxin, DABIL-4, composed of the catalytic and translocation domains of diphtheria toxin and murine IL-4. DABIL-4 showed specific cytotoxicity against triple-negative breast cancer (TNBC) cells in vitro. DABIL-4 also markedly inhibited TNBC tumor growth and metastasis in vivo. The primary activity of DABIL-4 was found to be depletion of IL-4R+ immune cells in combination with direct elimination of tumor cells. In conclusion, DABIL-4 targeting of both tumor and immunosuppressive host cells is a versatile and effective treatment strategy for TNBC.

immunology↗