Biology subjects

Guerrera, I. C.

Publications and source records attributed to Guerrera, I. C..

12 recordsLinked to original sources

bioRxiv2026

Mitochondrial dysfunction plays a key role in premature musculoskeletal aging in hypochondroplasia mouse model

Hypochondroplasia (HCH) is a mild form of chondrodysplasia, caused by variants in fibroblast growth factor receptor 3 (FGFR3). Today, the biological mechanism underlying musculoskeletal aging in HCH remains largely unknown. In this study, we show that Hch mice exhibit phenotypic traits of bone fragility and accelerated age-dependent articular cartilage and subchondral bone changes. Hch mice also presented decreased muscle strength and reduction in muscle fibers size. Furthermore, proteomics analyses of the cortical bone revealed that Hch mice follow a different aging trajectory than control. FGFR3 mutation leads to a premature boost of the mitochondrial processes forcing the mutant to reach a physiological state much earlier than the control. Together, these findings demonstrate that aging in Hch mice is accompanied by bone fragility and osteoarthritis-like changes. Proteomics analyses highlighted the key role for mitochondria in the cortical bone of Hch mice, providing insight into the mechanisms underlying premature aging in HCH.

genetics↗

bioRxiv2026

Multiomic Analysis Reveals an IFN-driven Cellular Landscape Effectively Targeted by Ruxolitinib in Hailey-Hailey Disease

Hailey-Hailey disease (HHD) is a rare autosomal dominant genodermatosis characterized by skin blistering and erosions in intertriginous regions, frequently complicated by secondary infections leading to substantial impairment in quality of life. No targeted mechanism-based therapies are currently available. Here, we applied a multiomics approach to define the molecular and cellular landscape of HHD. Bulk transcriptomics and proteomics uncovered a striking interferon (IFN) signature in HHD skin lesions. Single cell and spatial transcriptomics analyses revealed inflammatory niches, where immune, epithelial, vascular and stromal cells create a multi-compartment IFN-driven signaling network, that sustains a feed-forward amplification loop essential for chronic inflammation. Crucially, in nine patients with refractory HHD, topical treatment with the JAK1/2 inhibitor ruxolitinib led to rapid and durable re-epithelialization with drastic reduction in pain, itching, oozing and skin inflammation, significantly improving patient quality of life. Collectively, our findings identify IFN signaling as a key pathogenic driver in HHD and support topical JAK inhibition as an effective therapy, redefining the standard of care for individuals living with HHD.

pathology↗

bioRxiv2026

Serum Proteomics Profiling in Newborns: Differences Compared to Adults serum and new molecular markers for neonatal Sepsis

BackgroundNeonatal sepsis is a major cause of morbidity and mortality, particularly in low- and middle-income countries such as Senegal, where incidence is 78-104 per 1,000 live births and mortality exceeds 20 per 1,000, with case fatality rates around 36%. Diagnosis is difficult due to non-specific clinical signs and lack of molecular biomarkers, highlighting the need for improved early diagnostic molecular markers that could be applied even outside of hospital settings. ObjectivesCompare neonatal and adult serum proteomes to establish a reference and identify serum protein biomarkers of neonatal sepsis. MethodsSerum samples from Senegalese neonates and adults were analyzed using data-independent acquisition (DIA) proteomics on neat serum (Evosep-timsTOF HT platform). The cohort comprised 6 neonates with non-confirmed sepsis (NCS), 22 with confirmed sepsis (CS), 17 healthy newborn controls (HC), 6 unclassified and 20 healthy adults. Downstream analyses included differential protein abundance testing, unsupervised clustering, weighted gene co-expression network analysis (WGCNA), and correlation analyses with clinical parameters. ResultsWe identified 979{+/-}20 proteins in newborns versus 718{+/-}40 in adults. Newborns showed reduced immune-response proteins, a narrower dynamic range, and increased structural proteins such as collagens, consistent with immune immaturity and tissue development. Unsupervised WGCNA analysis led to a 53-protein cluster discriminated CS from NCS/HC. Some of these dysregulated proteins identified have already been reported in independent studies using different approaches in neonatal and/or adult sepsis. Our larger panel however of identified markers maps to three major biological processes involved in sepsis: (i) pathogen sensing (LBP, CD14), and acute-phase inflammation (e.g. CRP, SAA1/2, ORM1/2); (ii) innate immune activation and leukocyte recruitment (e.g., FCGR3A, CSF1R, CD163, CD206) and final platelet exhaustion and metabolic dysregulation, (e.g., PF4, PPBP, THBS1, GP5); (iii) endothelial injury and microvascular dysfunction with tissue remodeling (e.g., ICAM1, VCAM1, VWF, SPARC) and loss of protective lipoproteins and serpins (e.g., APOA1, APOA2, APOM, SERPINA4, SERPINA5) ConclusionThis study provides a very comprehensive neonatal serum proteome characterization and identifies, for the first time, a protein panel of proteins mapped to three major processes in sepsis.

pathology↗

bioRxiv2024

Extracellular vesicles from mucopolysaccharidosis type III microglia impair neurite growth

BackgroundIn mucopolysaccharidosis type III (MPS III), a pediatric neurodegenerative disorder, accumulation of abnormal glycosaminoglycans (GAGs) induces severe neuroinflammation by triggering the microglial pro-inflammatory cytokines production via a TLR4-dependent pathway. But the extent of the microglia contribution to the MPS III neuropathology remains unclear. Extracellular vesicles (EVs) mediate intercellular communication and are known to participate in the pathogenesis of adult neurodegenerative diseases. However, characterization of the molecular profiles of EVs released by MPS III microglia and their effects on neuronal functions have not been described. MethodsHere, we isolated EVs secreted by the microglial cells after treatment with GAGs purified from urines of MPS III patients (MPS III-EVs) to explore the EVs proteins and small RNA profiles using LC-MS/MS and RNA sequencing. We next performed a functional assay by immunofluorescence following wild-type (WT) or MPS III-EVs uptake by WT primary cortical neurons and analyzed their extensions metrics after staining of {beta}III-tubulin and MAP2 by confocal microscopy. ResultsFunctional enrichment analysis for both proteomics and RNA sequencing data from MPS III-EVs revealed a specific content involved in neuroinflammation and neurodevelopment pathways. Treatment of cortical neurons with MPS III-EVs induced a disease-associated phenotype demonstrated by a lower total neurite surface area, an impaired somatodendritic compartment, and a higher number of immature dendritic spines. ConclusionsThis study shows, for the first time, that GAGs from patients with MPS III can induce microglial secretion of EVs that deliver a specific molecular message to recipient naive neurons, while promoting the neuroinflammation, and depriving neurons of neurodevelopmental factors. This work provides a framework for further studies of biomarkers to evaluate efficiency of emerging therapies. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=117 SRC="FIGDIR/small/595318v2_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@8dfd3org.highwire.dtl.DTLVardef@9ece15org.highwire.dtl.DTLVardef@1ebc91eorg.highwire.dtl.DTLVardef@e10b00_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2023

The PP1 phosphatase exhibits pleiotropic roles controlling both the tachyzoite cell cycle and amylopectin-steady state levels in Toxoplasma gondii.

Virulence of apicomplexan parasites is based on their ability to divide rapidly to produce significant biomass. The regulation of their cell-cycle is therefore key to their pathogenesis. Phosphorylation is a crucial post-transcriptional modification that regulates many aspects of the eucaryotic cell cycle. The phosphatase PP1 is known to play a major role in the phosphorylation balance in eukaryotes. We explored the role of TgPP1 during the cell cycle of the tachyzoite form of the apicomplexan parasite Toxoplasma gondii. Using a conditional mutant strain, we show that TgPP1 regulates many aspects of the cell cycle including the proper assembly of the daughter cells inner membrane complex (IMC), the segregation of organelles and nuclear division. Unexpectedly, depletion of TgPP1 also results in the accumulation of amylopectin, a storage polysaccharide that is normally found in the latent bradyzoite form of the parasite. Using transcriptomics and phosphoproteomics, we show that TgPP1 mainly acts through post-transcriptional mechanisms by dephosphorylating target proteins including IMC proteins. TgPP1 also dephosphorylate a protein bearing a starch binding domain. Mutagenesis analysis reveals that the targeted phospho-sites are linked to the ability of the parasite to regulate amylopectin steady-state levels. Therefore, we show that TgPP1 has pleiotropic roles during the tachyzoite cell cycle regulation, but also regulates amylopectin accumulation.

microbiology↗

bioRxiv2023

Pancreatic islet cell stress induced by insulin-degrading enzyme deficiency promotes islet regeneration and protection from autoimmune diabetes

Appropriate tuning of protein homeostasis through mobilization of the unfolded protein response (UPR) is key to the capacity of pancreatic beta cells to cope with highly variable demand for insulin synthesis. An efficient UPR ensures a sufficient beta cell mass and secretory output but can also affect beta cell resilience to autoimmune aggression. The factors regulating protein homeostasis in the face of metabolic and immune challenges are insufficiently understood. We examined beta cell adaptation to stress in mice deficient for insulin-degrading enzyme (IDE), a ubiquitous protease with high affinity for insulin and genetic association with type 2 diabetes. IDE deficiency induced a low-level UPR in both C57BL/6 and autoimmune non-obese diabetic (NOD) mice, associated with rapamycin-sensitive beta cell proliferation strongly enhanced by proteotoxic stress. Moreover, in NOD mice, IDE deficiency protected from spontaneous diabetes and triggered an additional independent pathway, conditional on the presence of islet inflammation but inhibited by proteotoxic stress, highlighted by strong upregulation of regenerating islet-derived protein 2, a protein attenuating autoimmune inflammation. Our findings establish a key role of IDE in islet cell protein homeostasis, identify a link between low-level UPR and proliferation, and reveal an UPR-independent anti-inflammatory islet cell response uncovered in the absence of IDE of potential interest in autoimmune diabetes.

cell biology↗

bioRxiv2023

Characterization of the Plasmodium berghei regulatory AAA-ATPase subunit Rpt3 as an activator of Protein Phosphatase 1: direct and indirect evidence

The 26S proteasome is the main proteolytic machine involved in protein degradation, thus contributing to homeostasis or stress response of eukaryotic cells. This macromolecular complex, consisting of a 20S core particle assembled with one or two 19S regulatory particles, is highly regulated by phosphorylation. Here we describe the Plasmodium berghei proteasome AAA-ATPase regulatory subunit Rpt3 and show that it binds to protein phosphatase 1, the major parasite phosphatase. In addition, PbRpt3 regulates the activity of the phosphatase both in vitro and in a heterologous model of Xenopus oocytes. Using mutagenesis approaches, we observed that the RVXF motifs of PbRpt3 are involved in this binding and activity. Further use of Xenopus oocyte model and mutagenesis based on the 3D model that we established revealed that the binding capacity of PbRpt3 to ATP may also contribute to its phosphatase-regulating activity. In the parasite, reverse genetic studies suggested an essential role for PbRpt3 since no viable knock-out line could be obtained. Additionally, immunoprecipitation assays followed by mass spectrometry analyses using transgenic PbRpt3-tagged parasites not only confirmed that PbRpt3 belongs to the 19S regulatory particle of the proteasome, but also revealed potential interaction with proteins already shown to play a role in the phospholipid membrane dynamics.

microbiology↗

bioRxiv2023

Tur1 regulates alternative TSS usage in Cryptococcus

Alternative transcription start site (TSS) usage regulation has been identified as a major means of gene expression regulation in metazoans. However, in fungi, its impact remains elusive as its study has thus far been restricted to model yeasts. Here, we first re-analysed TSS-seq data to define genuine TSS clusters in two species of pathogenic Cryptococcus. We identified two types of TSS clusters associated with specific DNA sequence motifs. Our analysis also revealed that alternative TSS usage regulation in response to environmental cues is widespread in Cryptococcus, altering gene expression and protein targeting. Importantly, we performed a forward genetic screen to identify a unique transcription factor (TF) named Tur1, which regulates alternative TSS (altTSS) usage genome-wide when cells switch from exponential phase to stationary phase. ChiP-Seq and DamID-Seq analyses suggest that at some loci the role of Tur1 might be direct. Tur1 has been previously shown to be essential for virulence in C. neoformans. We demonstrated here that a tur1{Delta} mutant strain is more sensitive to superoxide stress and phagocytosed more efficiently by macrophages than the wild-type (WT) strain.

molecular biology↗

bioRxiv2023

Characterization of GEXP15 as a potential regulator of Protein Phosphatase 1 and partner of ribosomal complex in Plasmodium falciparum.

The Protein Phosphatase type 1 catalytic subunit (PP1c) (PF3D7_1414400) operates in combination with various regulatory proteins to specifically direct and control its phosphatase activity. However, little is known about this phosphatase and its regulators in the human malaria parasite, Plasmodium falciparum. To address this gap, we conducted a comprehensive investigation into structural and functional characteristics of a conserved Plasmodium-specific regulator called Gametocyte EXported Protein 15, GEXP15 (PF3D7_1031600). Through in silico analysis, we identified three significant regions of interest in GEXP15: an N-terminal region housing a PP1-interacting RVxF motif, a conserved domain whose function is unknown and a GYF-like motif that potentially facilitates specific protein-protein interactions. To further elucidate the role of GEXP15, we conducted in vitro interaction studies, which demonstrated a direct interaction between GEXP15 and PP1 via the RVxF binding motif. This interaction was found to enhance phosphatase activity of PP1. Additionally, utilizing a transgenic GEXP15-tagged line and live microscopy, we observed high expression of GEXP15 in late asexual stages of the parasite, with localization predominantly in the parasite nucleus. Immunoprecipitation assays followed by mass spectrometry analyses revealed GEXP15s interaction with ribosomal and RNA binding proteins. Furthermore, through pulldown analyses of recombinant functional domains of GEXP15 tagged with a His-tag, we confirmed its binding to the ribosomal complex via the GYF domain. Collectively, our study sheds light on the PfGEXP15-PP1-ribosome interaction, which plays a crucial role in protein translation. These findings suggest that PfGEXP15 could serve as a potential target for the development of malaria drugs.

microbiology↗

bioRxiv2021

The Pentose Phosphate Pathway constitutes a major metabolic hub in pathogenic Francisella

Metabolic pathways are now considered as intrinsic virulence attributes of pathogenic bacteria and hence represent potential targets for anti-bacterial strategies. Here, we addressed the role of the pentose phosphate pathway (PPP) and its connections with other metabolic pathways in the pathophysiology of Francisella novicida. The involvement of the PPP in Francisella intracellular life cycle was first demonstrated with the study of PPP inactivation mutants. Indeed, inactivation of tktA, rpiA or rpe genes, severely impaired intramacrophagic multiplication during the first 24 hours. Time-lapse video microscopy demonstrated that rpiA and rpe mutants were able to resume late intracellular bacterial multiplication. To get further insight into the links between the PPP and other metabolic networks of the bacterium, we next performed a thorough proteo-metabolomic analysis of these mutants. We show that the PPP constitutes a major bacterial metabolic hub with multiple connections with glycolysis, tricarboxylic acid cycle and other pathways, such as fatty acid degradation and sulfur metabolism. Hence, our study highlights how the PPP is instrumental to Francisella pathogenesis and growth in its intracellular niche.

microbiology↗

bioRxiv2018

Persistent Staphylococcus aureus infections in children with chronic lung disease: a multi-omics analysis of bacterial adaptation to define novel therapeutic approaches

BackgroundChronic lung infection of cystic fibrosis (CF) patients by Staphylococcus aureus is a well-established epidemiological fact. Indeed, S. aureus is the most commonly identified pathogen in the lungs of CF patients. Strikingly the molecular mechanisms underlying S. aureus persistency are not understood.\n\nMethodsWe selected pairs of sequential S. aureus isolates from 3 patients with CF and from one patient with non-CF chronic lung disease. We used a combination of genomic, proteomic and metabolomic approaches with functional assays for in-depth characterization of S. aureus long-term persistence.\n\nResultsFor the first time, we show that late S. aureus isolates from CF patients have an increased ability for intracellular survival in CFBE-F508del cells compared to ancestral early isolates. Importantly, the increased ability to persist intracellularly was confirmed for S. aureus isolates within the own patient F508del epithelial cells. An increased ability to form biofilm was also demonstrated.\n\nFurthermore, we identified the underlying genetic modifications inducing altered protein expression profiles and notable metabolic changes. These modifications affect several metabolic pathways and virulence regulators that could constitute therapeutic targets.\n\nConclusionsOur results strongly suggest that the intracellular environment might constitute an important niche of persistence and relapse necessitating adapted antibiotic treatments.\n\nSummaryS. aureus persists for years in the lungs of patients with cystic fibrosis despite antibiotic therapies. We demonstrate that S. aureus adaptation leads to increased intracellular persistence suggesting a key role for intracellular niche during S. aureus chronic lung infection.

microbiology↗

bioRxiv2018

Cystinosin regulates kidney inflammation through its interaction with galectin-3

Inflammation is implicated in the pathogenesis of many disorders. Here, we show that cystinosin, protein defective in the lysosomal storage disorder cystinosis, is a critical regulator of galectin-3 during inflammation. Cystinosis is a lysosomal storage disorder and despite ubiquitous expression of cystinosin, kidney is the primary organ to be impacted by the disease. Here, we show that cystinosin interacts with galectin-3 and enhances its lysosomal localization and degradation. Galectin-3 is also found overexpressed in the kidney of the mouse model of cystinosis, Ctns-/-mice. Absence of galectin-3 in Ctns-/- mice led to a better renal function and structure, and decreased macrophage/monocyte infiltration in the kidney. Finally, galectin-3 interacts with a protein implicated in the recruitment of monocytes and macrophages during inflammation, Monocyte Chemoattractant Protein-1 (MCP1), that was found increased in the serum of Ctns-/- mice. These findings highlight a new role of cystinosin and galectin-3 interaction in inflammation, providing a mechanistic explanation for kidney disease pathogenesis in cystinosis, which may lead to the identification of new drug targets to delay its progression.

molecular biology↗