Biology subjects

Piccirillo, C. A.

Publications and source records attributed to Piccirillo, C. A..

6 recordsLinked to original sources

bioRxiv2025

Autoantibodies targeting CRB2 and Nephrin correlate with extrafollicular B cells in idiopathic podocytopathies

Idiopathic podocytopathies lack mechanistic biomarkers and rely on empirical immunosuppression, yet the recent discovery of autoantibodies against slit diaphragm proteins implicates podocyte-directed autoimmunity as a driver of podocyte injury. However, the immune mechanisms underlying autoreactivity and phenotypic heterogeneity, particularly across age groups, remain unclear. Here, we identify expansion of CD21low T-bet+ atypical B cells (atBCs) in peripheral blood as a shared immunologic feature across idiopathic podocytopathies. In children, atBC accumulation was associated with heightened B cell activation, favoring extrafollicular responses and plasmablast differentiation. Serologic profiling revealed that autoantibodies against the slit diaphragm protein CRB2 are highly prevalent across disease phenotypes and frequently co-occur with anti-Nephrin antibodies, particularly in adults. Autoantibody abundance correlated with atBC expansion in affected children, implicating extrafollicular B cell responses as a key pathway for their generation, whereas adults showed additional involvement of follicular pathways. Complementary mouse modeling demonstrated intermolecular epitope spreading as a mechanism linking anti-CRB2 and anti-Nephrin autoreactivity. Together, these findings define a shared immune framework for idiopathic podocytopathies in which extrafollicular B cell responses drive autoreactivity to multiple slit diaphragm proteins, with implications for biomarker development and therapeutic stratification.

immunology↗

bioRxiv2024

GDNF family receptor alpha-like (GFRAL) expression is restricted to the caudal brainstem

The TGF-{beta} cytokine, growth differentiation factor 15 (GDF15) is a critical mediator of the physiologic response to a range of cellular stresses. While circulating levels of GDF15 are normally very low, these levels increase substantially under a number of acute and chronic pathogenic states including mycotoxin exposure, infection and cancer. GDF15 controls a range of physiologic outputs including reduced appetite, gastric motility, hyperalgesia, emesis, energy expenditure and immune cell function via the GDNF family receptor alpha-like (GFRAL). While the area postrema and nucleus of the solitary tract (AP/NTS) within the caudal brainstem are the only known sites of Gfral-expressing cells, Gfral may also be expressed in other cell types. We therefore utilized single molecule in-situ hybridizations and genetic mouse models to label Gfral-expressing cells from development to adult mouse. With both approaches, we found Gfral-labelled cells in the brainstem and extremely rare Gfral-labelled cells in peripheral tissues in the mouse under normal physiological conditions. Confirming these findings, single nucleus RNA-sequencing of human tissues demonstrated nearly undetectable levels of Gfral mRNA in sites outside the AP/NTS. Our findings confirm AP/NTS neurons are the major site of Gfral expression.

molecular biology↗

bioRxiv2023

The extrafollicular B cell response is a hallmark of childhood idiopathic nephrotic syndrome.

An autoimmune B cell origin for childhood idiopathic nephrotic syndrome (INS) is predicted based on the efficacy of rituximab (RTX) at maintaining long-term remission from proteinuria. Knowledge regarding the nature of the culprit B cell response is very limited. Using single-cell RNA-sequencing, we demonstrate that a B cell transcriptional program poised for effector functions represents the major immune perturbation in the blood of children with active INS. This was conferred by the engagement of an extrafollicular B cell response marked by the expansion of atypical B cells (atBCs), marginal zone-like B cells, and antibody-secreting cells (ASCs). In flow-based analyses of blood from 13 children with active INS and 24 healthy donors, this was reflected by the proliferation of RTX-sensitive extrafollicular (CXCR5-) CD21low T-bet+ CD11c+ atBCs, and short-lived T-bet+ ASCs. Together, our study provides evidence for an extrafollicular origin for humoral immunity in active INS.

immunology↗

bioRxiv2023

BCG administration promotes the long-term protection afforded by a single-dose intranasal adenovirus-based SARS-CoV-2 vaccine

Despite medical interventions and several approved vaccines, the COVID-19 pandemic is continuing into its third year. Recent publications have explored single-dose intranasal (i.n.) adenovirus-based vaccines as an effective strategy for curbing SARS-CoV-2 in naive animal models. However, the effects of prior immunizations and infections have yet to be considered within these models. Here, we investigate the immunomodulatory effects of Mycobacterium bovis BCG pre-immunization on a subsequent S-protein expressing i.n. Ad vaccination, termed Ad(Spike). We found that Ad(Spike) alone conferred long-term protection from severe SARS-CoV-2 pathology within a mouse model, yet it was unable to limit initial infection 6 months post-vaccination. While i.n. Ad(Spike) retains some protective effect after 6 months, a single administration of BCG-Danish prior to Ad(Spike) vaccination potentiates its ability to control viral replication of the B.1.351 SARS-CoV-2 variant within the respiratory tract. Though BCG-Danish had no effect on the ability of Ad(Spike) to generate and maintain humoral immunity, it promoted the generation of cytotoxic and Th1 responses over suppressive FoxP3+ TREG cells in the lungs of infected mice. These data demonstrate a novel vaccination strategy that may prove useful in limiting future viral pandemics by potentiating the long-term efficacy of next generation mucosal vaccines within the context of the safe and widely distributed BCG vaccine. One sentence summaryBCG enhances anti-SARS-CoV-2 immunity and protection afforded by a novel adenovirus-vectored vaccine.

immunology↗

bioRxiv2022

Selection for immune evasion in SARS-CoV-2 revealed by high-resolution epitope mapping combined with genome sequence analysis

A deeper understanding of the molecular determinants that drive humoral responses to coronaviruses, and in particular severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is critical for improving and developing diagnostics, therapies and vaccines. Moreover, viral mutations can change key antigens in a manner that alters the ability of the immune system to detect and clear infections. In this study, we exploit a deep serological profiling strategy coupled with an integrated, computational framework for the analysis of SARS-CoV-2 humoral immune responses of asymptomatic or recovered COVID-19-positive patients relative to COVID-19-negative patients. We made use of a novel high-density peptide array (HDPA) spanning the entire proteomes of SARS-CoV-2 and endemic human coronaviruses to rapidly identify B cell epitopes recognized by distinct antibody isotypes in patients blood sera. Using our integrated computational pipeline, we then evaluated the fine immunological properties of detected SARS-CoV-2 epitopes and relate them to their evolutionary and structural properties. While some epitopes are common across all CoVs, others are private to specific hCoVs. We also highlight the existence of hotspots of pre-existing immunity and identify a subset of cross-reactive epitopes that contributes to increasing the overall humoral immune response to SARS-CoV-2. Using a public dataset of over 38,000 viral genomes from the early phase of the pandemic, capturing both inter- and within-host genetic viral diversity, we determined the evolutionary profile of epitopes and the differences across proteins, waves and SARS-CoV-2 variants, which have important implications for genomic surveillance and vaccine design. Lastly, we show that mutations in Spike and Nucleocapsid epitopes are under stronger selection between than within patients, suggesting that most of the selective pressure for immune evasion occurs upon transmission between hosts.

genomics↗

bioRxiv2020

The MNK1/2-eIF4E axis contributes to phenotype switching, melanoma progression, and resistance to immunotherapy.

Melanomas commonly undergo a phenotype switch, from a proliferative to an invasive state. Melanoma plasticity exhibited as phenotype switching contributes to immunotherapy resistance, however the mechanisms are not completely understood and thus therapeutically unexploited. Here, using a transgenic melanoma mouse model, we demonstrated a critical role of the MNK1/2-eIF4E axis in melanoma plasticity and resistance to immunotherapy. We showed that phospho-eIF4E deficient murine melanomas express high levels of melanocytic antigens, with similar results verified in patient melanomas. Mechanistically, we identified that phospho-eIF4E controls the translation of NGFR, a critical effector of phenotype switching. In patients with melanoma, the expression of MKNK1, the kinase for eIF4E, positively correlated with markers of immune exhaustion. Genetic ablation of phospho-eIF4E reprogrammed the immunosuppressive microenvironment, exemplified by lowered production of inflammatory factors and increased CD8+ T cell infiltrates. Blocking phospho-eIF4E, using MNK1/2 inhibitors, offers a new strategy to inhibit melanoma plasticity and improve the survival response to anti-PD-1 immunotherapy.

cancer biology↗