Biology subjects

Phung, W.

Publications and source records attributed to Phung, W..

3 recordsLinked to original sources

bioRxiv2023

Exposing the molecular heterogeneity of glycosylated biotherapeutics

Glycosylated biotherapeutics are an emerging class of drugs with high molecular heterogeneity, which can affect their safety and efficacy. Characterizing this heterogeneity is crucial for drug development and quality assessment, but existing methods are limited in their ability to analyze intact glycoproteins. Here, we present a new approach to glycoform fingerprinting that uses proton-transfer charge-reduction with gas-phase fractionation to analyze intact glycoproteins by mass spectrometry. The method provides a detailed landscape of the intact molecular weights present in biotherapeutic protein preparations in a single experiment and offers insights into glycoform composition when coupled with a suitable bioinformatic strategy. We tested the approach on various biotherapeutic molecules, including Fc-fusion, VHH-fusion, and peptide-bound MHC class II complexes to demonstrate efficacy in measuring the proteoform-level diversity of biotherapeutics. Notably, we inferred the glycoform distribution for hundreds of molecular weights for the eight-times glycosylated fusion drug IL22-Fc, enabling correlations between glycoform sub-populations and the drugs pharmacological properties. Our method is broadly applicable and provides a powerful tool to assess the molecular heterogeneity of emerging biotherapeutics.

biochemistry↗

bioRxiv2022

Loss of the intracellular enzyme QPCTL limits chemokine function and reshapes myeloid infiltration to augment tumor immunity

Tumor-associated macrophages are composed of distinct populations arising from monocytes or tissue macrophages, with a poorly understood link to disease pathogenesis. Here, we demonstrate that mouse monocyte migration was supported by glutaminyl-peptide cyclotransferase-like (QPCTL), an enzyme that mediates N-terminal modification of several subtrates, including the monocyte-chemoattractants CCL2 and CCL7, protecting them from proteolytic inactivation. Knockout of Qpctl disrupted monocyte homeostasis, attenuated tumor growth and reshaped myeloid cell infiltration, with loss of monocyte-derived populations with immunosuppressive and pro-angiogenic profiles. Antibody blockade of the receptor CSF1R, which more broadly eliminates tissue macrophages, reversed tumor growth inhibition in Qpctl-/- mice, and prevented lymphocyte infiltration. Modulation of QPCTL synergized with anti-PD-L1 to expand CD8+ T cells and limit tumor growth. QPCTL inhibition constitutes an effective approach for myeloid cell-targeted cancer immunotherapy.

immunology↗

bioRxiv2018

Proteomic Analysis of NRROS Interactome Reveals the Presence of Chaperones and Mediators of the ERAD Pathway

Negative regulator of reactive oxygen species (NRROS, previously called LRRC33) is a leucine-rich repeat (LRR) domain containing, ER-resident transmembrane protein expressed primarily in lymphoid organs, especially in myeloid cells. We have previously demonstrated that NRROS regulates reactive oxygen species production by phagocytic cells by mediating degradation of NOX2 (gp91phox), a component of NOX2 complex responsible for the oxidative burst in these cells. Since LRR is the only functional domain in NRROS, it is likely to interact with other proteins for its biological functions. Here, by performing immunoprecipitation of NRROS and mass spectrometric analysis, we describe the NRROS interactome in macrophages and demonstrate that NRROS interacts with molecular chaperones/co-chaperones and mediators of the endoplasmic reticulum associated degradation (ERAD) pathway such as calnexin, suggesting a broader role for NRROS in protein biosynthesis and the ER quality control machinery.

biochemistry↗