Biology subjects

Barone, M.

Publications and source records attributed to Barone, M..

7 recordsLinked to original sources

bioRxiv2026

Distinct macrophage and T cell programs shape pancreatic inflammation during metabolic stress and aging

Type 2 diabetes is linked to systemic inflammation driven by metabolic stress and aging. Although pancreatic inflammation associated with these factors is well documented, the dynamics of immune cell populations and their molecular changes remain poorly understood. We characterized immune cell alterations in the pancreas and pancreatic islets during Western diet (WD) feeding and aging using imaging mass cytometry (IMC) and single-cell RNA sequencing (scRNA-seq). Spatial and transcriptional analyses were performed to define immune cell subtype composition, activation states, and inferred cell-cell communication programs under metabolic and age-related stress conditions. Our analyses identified expansion of an F4/80low macrophage subtype and activated effector-like CD8+ T cells throughout the pancreas during WD feeding and aging. Within pancreatic islets, single-cell RNA sequencing identified a type I interferon-responsive macrophage population with low F4/80 expression that expanded during overnutrition. Notably, the type I interferon responses elicited by these stressors diverged: aging was associated with a more canonical type I interferon response, whereas overnutrition induced a broader response that included STAT3-associated transcriptional programs. We further provide evidence for enhanced cytokine-mediated communication between macrophages and a CD8+ cytotoxic T-cell population under overnutrition and aging. These findings show that metabolic stress and aging remodel pancreatic inflammation through overlapping but distinct immune mechanisms, involving expansion of F4/80low macrophages, activation of divergent type I interferon programs, and enhanced macrophage-CD8+ T-cell communication. Together, these findings suggest that distinct therapeutic approaches may be required to preserve islet function in type 2 diabetes driven by metabolic stress versus aging. Article HighlightsO_LIMetabolic stress and aging remodel pancreatic inflammation through overlapping but distinct immune mechanisms. C_LIO_LISpatial and single-cell analyses identified conserved remodeling of pancreatic macrophage populations accompanied by activation of cytotoxic T-cell responses during metabolic stress and aging. C_LIO_LIIn pancreatic islets, macrophages exhibited distinct type I interferon-associated transcriptional programs, with aging showing a more canonical interferon response and metabolic stress eliciting a broader inflammatory program that included STAT3-associated transcriptional signatures. C_LIO_LIThese findings provide a framework for understanding how metabolic stress and aging differentially shape pancreatic inflammation. C_LI

cell biology↗

bioRxiv2026

Protein-ligand binding kinetics are primarily controlled by the protein, not the ligand.

Protein-ligand interactions underpin biological regulation and drug action, with both binding affinity and binding kinetics shaping functional outcomes. By analysing kinetic data for 4,311 protein-small-molecule pairs, we find that when association occurs below the diffusion-controlled limit, the rates of ligand association (kon) and dissociation (koff) are primarily determined by how the initial encounter complex reorganizes into the final bound state, and that this reorganization is governed chiefly by the intrinsic dynamic properties of the protein rather than by structural features of the ligand. Counterintuitively, therefore, koff exhibits minimal dependence on ligand structure, so that dissociation proceeds through protein-gated conformational transitions rather than through direct rupture of protein-ligand contacts. This mechanistic behaviour stands in marked contrast to that for protein-protein complexes, based on an analysis of 1,561 interactions. Together, these findings challenge prevailing assumptions regarding the molecular determinants of small-molecule binding kinetics, and have broad implications for rationally modulating protein-ligand interactions and drug-target residence times.

biochemistry↗

bioRxiv2025

MyoRep: a novel reporter system to detect early muscle atrophy in vitro and in vivo

Muscle atrophy occurs during physiological (i.e., fasting, aging) and pathological (i.e., amyotrophic lateral sclerosis, cancer) conditions and anticipates death. Since not all patients will undergo muscle wasting, it would be highly useful to identify them soon to intervene early. We have studied the promoters/enhancers of a subset of atrophy-related genes or atrogenes upregulated in muscles of rodents during various kinds of atrophy (i.e., disuse, diabetes, cancer, fasting, uremia) for their ability to induce early atrophy. Comparing their upstream non-coding regions, using as backbone MuRF1 promoter (one of the earliest muscle-specific genes induced by wasting), we cloned various promoters upstream of a doubled reporter system (FLuciferase/tdTomato). Through in vitro and in vivo studies in mice subjected to denervation or cancer injection, we selected a sequence (i.e., MyoRep) able to predict atrophy upon cut of the sciatic nerve or cancer. In vivo imaging of MyoRep mice emit a bioluminescent signal earlier than muscle loss. Importantly, MyoRep was unable to sense atrophy during fasting or physiological variations following the circadian rhythms. Since MyoRep can discriminate muscle loss due to pathological conditions from physiological ones anticipating wasting, it represents an unprecedented tool to predict it early in various diseases with local or systemic atrophy.

genetics↗

bioRxiv2024

Asymmetric Engagement of Dimeric CRL3KBTBD4 by the Molecular Glue UM171 Licenses Degradation of HDAC1/2 Complexes

UM171 is a potent small molecule agonist of ex vivo human hematopoietic stem cell (HSC) self-renewal1, a process that is tightly controlled by epigenetic regulation. By co-opting KBTBD4, a substrate receptor of the CULLIN3-RING E3 ubiquitin ligase complex, UM171 promotes the degradation of members of the CoREST transcriptional corepressor complex, thereby limiting HSC attrition2,3. However, the direct target and mechanism of action of UM171 remain unclear. Here, we reveal that UM171 acts as a molecular glue to induce high-affinity interactions between KBTBD4 and HDAC1 to promote the degradation of select HDAC1/2 corepressor complexes. Through proteomics and chemical inhibitor studies, we discover that the principal target of UM171 is HDAC1/2. Cryo-electron microscopy (cryo-EM) analysis of dimeric KBTBD4 bound to UM171 and the LSD1-HDAC1-CoREST complex unveils an unexpected asymmetric assembly, in which a single UM171 molecule enables a pair of KBTBD4 KELCH-repeat propeller domains to recruit HDAC1 by clamping on its catalytic domain. One of the KBTBD4 propellers partially masks the rim of the HDAC1 active site pocket, which is exploited by UM171 to extend the E3-neo-substrate interface. The other propeller cooperatively strengthens HDAC1 binding via a separate and distinct interface. The overall neomorphic interaction is further buttressed by an endogenous cofactor of HDAC1-CoREST, inositol hexakisphosphate, which makes direct contacts with KBTBD4 and acts as a second molecular glue. The functional relevance of the quaternary complex interaction surfaces defined by cryo-EM is demonstrated by in situ base editor scanning of KBTBD4 and HDAC1. By delineating the direct target of UM171 and its mechanism of action, our results reveal how the cooperativity offered by a large dimeric CRL E3 family can be leveraged by a small molecule degrader and establish for the first time a dual molecular glue paradigm.

molecular biology↗

bioRxiv2024

Consumption of only wild foods induces large-scale, partially-persistent alterations to the gut microbiome

The composition of the gut microbiome (GM) affects human health and varies among lifestyles. Adopting more "traditional" diets could lead to substantive and health-associated changes in the GM. However, research has focused on diets including domesticated foods. For most of our evolutionary history, humans consumed only wild foods. We explored the impact of a wild-food-only (WF) diet on the GM composition. One participant collected daily fecal samples and recorded daily food consumption over an eight-week period, the middle four weeks of which he consumed only wild foods (nuts, fruits and leafy greens, wild deer, and fish). Samples were profiled through 16S rRNA amplicon sequencing and the species identified by oligotyping. The WF diet altered the GM composition, and the magnitude of the changes is larger than in other diet interventions. However, no new GM taxa, including "old friends" appeared; instead, the relative proportions of already-present taxa shifted. There is a clear successional shift from the pre-, during- and post-WF diet. The GM is very sensitive to the change from a "Western" diet to a WF diet, likely reflecting the different macro- and micronutrient properties of the consumed foods.

microbiology↗

bioRxiv2019

Gut microbiome structure and adrenocortical activity in dogs with aggressive and phobic behavioral disorders

Accompanying human beings since the Paleolithic period, dogs has been recently regarded as a reliable model for the study of the gut microbiome connections with health and disease. In order to provide some glimpses on the connections between the gut microbiome layout and host behavior, we profiled the phylogenetic composition and structure of the canine gut microbiome of dogs with aggressive (n = 17), phobic (n = 15) and normal behavior (n = 17). According to our findings, aggressive behavioral disorder was found to be characterized by a peculiar gut microbiome structure, with high biodiversity and enrichment in generally subdominant bacterial genera. On the other hand, phobic dogs were enriched in Lactobacillus, a bacterial genus with known probiotic and psychobiotic properties. Although further studies are needed to validate our findings, our work supports the intriguing opportunity that different behavioral phenotypes in dogs may be associated with peculiar gut microbiome layouts, suggesting possible connections between the gut microbiome and the central nervous system and indicating the possible adoption of probiotic interventions aimed at restoring a balanced host-symbiont interplay for mitigating behavioral disorders.

microbiology↗

bioRxiv2018

Gut microbiome response to a modern Paleolithic diet in a Western lifestyle context

The progressive reduction of gut microbiome (GM) biodiversity along human evolutionary history has been found to be particularly exacerbated in Western urban compared to traditional rural populations, and supposed to contribute to the increasing incidence of chronic non-communicable diseases. Together with sanitation, antibiotics and C-section, the Western diets, low in microbiota-accessible carbohydrates (MACs) while rich in industrialized and processed foods, are considered one of the leading causes of this shrinkage. However, significant questions remain unanswered, especially whether high-MAC low-processed diets may be sufficient to recover GM diversity in Western urban populations. Here, we profiled the GM structure of urban Italian subjects adhering to the modern Paleolithic diet (MPD), a dietary pattern featured by high consumption of MACs and low-to-zero intake of refined sugars and processed foods, and compared data with other Italian individuals following a Mediterranean Diet (MD), as well as worldwide traditional hunter-gatherer populations from previous publications. Notwithstanding a strong geography effect on the GM structure, our results show an unexpectedly high degree of GM biodiversity in MPD subjects, which well approximates that of traditional populations. Increasing the consumption of MACs at the expense of refined sugars, and minimizing the intake of processed foods, both hallmarks of the MPD, could be the key to rewild the Western microbiota, counteracting the loss of GM diversity and thus restoring evolutionarily important functionality to our gut for improved human health.

microbiology↗