👤 Pablo Prieto

Diabetes accelerates atherosclerosis by driving persistent vascular inflammation. MicroRNA-155 (miR-155) is a post-transcriptional regulator of inflammatory genes, while suppressor of cytokine signaling 1 (Socs1) limits Janus kinase (JAK)/signal transducer and activator of transcription (STAT)-mediated cytokine responses. We explored how the imbalance between miR-155-5p and Socs1 contributes to atherosclerotic plaque progression in diabetes. Apolipoprotein E knockout (ApoE-/-) mice were studied in two settings: age-dependent atherosclerosis progression under non-diabetic conditions, and streptozotocin-induced diabetes to model accelerated atherosclerosis. Diabetic mice received a miR-155-5p inhibitor, a Socs1-expressing adenovirus, or respective controls. Lesion size, composition, and gene expression were analyzed. Cultured vascular smooth muscle cells (VSMCs) and macrophages were transfected with miR-155-5p mimic/inhibitor and Socs1 siRNA/plasmid to assess inflammatory responses, phenotypes, and efferocytosis under diabetic-like conditions. During atherosclerosis progression, vascular miR-155-5p inversely correlated with Socs1 and positively with lesion size, while Socs1 correlated negatively with plaque burden. In diabetic mice, miR-155-5p inhibition reduced lesion area, lipid/collagen and macrophage/VSMC ratios, pro-inflammatory cytokines, M1 macrophages and synthetic VSMC markers, while increasing Socs1, M2 and contractile VSMC genes. Socs1 gene transfer reproduced these effects by reducing miR-155-5p and Stat1 expression, and lesion size. In vitro, miR-155-5p mimic suppressed Socs1, activated STAT1 and inflammatory phenotypes in macrophages and VSMCs, whereas miR-155-5p inhibition had opposite effects. Socs1 silencing amplified inflammation, and its overexpression counteracted miR-155-5p actions. Moreover, miR-155-5p inhibition reduced soluble Mer receptor tyrosine kinase (MerTK) in plaques and macrophages, indicating improved efferocytosis, whereas the mimic promoted macrophage MerTK shedding and impaired apoptotic cell clearance. Reciprocal regulation between miR-155-5p and Socs1 influences vascular inflammation, phenotypic changes, and defective efferocytosis in a diabetic context. Targeting this axis may restore resolution mechanisms and enhance plaque stability in diabetes-associated vascular disease. The online version contains supplementary material available at 10.1186/s12933-026-03121-3. Show less

Merkel cell carcinomas (MCCs) exhibit diverse molecular profiles, often categorized by their association with Merkel cell polyoma virus (MCPyV). MCPyV-associated MCCs typically display a low tumor mutational burden (TMB), lacking both somatic mutations and ultraviolet signature. By contrast, MCPyV-negative MCCs commonly arise in sun-exposed skin and frequently exhibit a high TMB, along with TERT promoter mutation (TPM) and somatic mutations, particularly in TP53 and RB1 . Gene fusions are exceedingly rare in MCCs, and their specific frequency and fusion transcripts remain largely unexplored. Here, we present a unique case of MCPyV-associated MCC characterized by NSD3::FGFR1 fusion, representing a novel fusion transcript not previously reported in MCCs. A 72-year-old White man presented with a cyst-like nodule on the left elbow, which had progressively increased in size over a span of 6 months. Excisional biopsy specimen revealed a neuroendocrine carcinoma diffusely expressing CK20 (perinuclear dot-like), synaptophysin, CD56, NSE, and MCPyV, consistent with MCC. Next-generation sequencing identified a NSD3::FGFR1 fusion without any additional somatic mutations, including TP53 and RB1 mutations, or TPM. Although NSD3::FGFR1 fusion has been sporadically reported in other solid tumors, such as pulmonary squamous cell carcinoma, its identification in an MCC is unprecedented to our knowledge. This novel finding not only underscores the uniqueness of our case but also contributes to the evolving understanding of the molecular landscape of MCCs, particularly MCPyV-associated MCCs. Show less

Osteoarthritis (OA) can be experimentally induced by injecting monoiodoacetate (MIA) in the knee capsule of mice. Our aim was to assess the role of nerve growth factor (NGF)/TrkA axis in OA, identifying differentially expressed genes (DEGs) and functional pathways in knee-innervating dorsal root ganglia (DRG) from wild type (WT) and hypersensitive TrkAP782S knock-in (KI) mice after MIA injection. We performed saline or MIA-injection in knee joints of WT and KI mice and harvested L3-L5 DRGs at 5 and 21 days after injection, pooling males and females (n = 4/group). RNA was extracted, and microarray analysis was performed. Upon comparisons between different groups, identification of DEGs was defined as adjusted P < 0.01. Gene ontology, pathway analysis and protein interactions were conducted using Gene Set Enrichment Analysis over Gene Ontology and REACTOME databases, and STRING database. For each comparison regarding genotype (WT vs KI), numerous DEGs were identified but with limited overlap, being Lingo1, Socs2, and Slc4a4 already related to pain, OA and/or NGF/TrkA axis. Regarding comparisons of early vs late OA (D5 vs D21), many more DEGs were revealed including genes previously implicated in OA such as Gal, Gja1, and Lep. Moreover, we found enriched pathways in the KI_MIA group, such as gene expression, neuronal system and signal transduction, in which NTRK1 and MAPK pathways indicate specificity in the NGF/TrkA axis and in the transition from early to late OA pain. Our results identify new mouse DEGs and pathways that demonstrate the relevance of the NGF/TrkA system in the chronification of OA pain. Show less

Next generation sequencing (NGS) has expanded the diagnostic paradigm turning the focus to the growth plate. The aim of the study was to determine the prevalence of variants in genes implicated in skeletal dysplasias in probands with short stature and mild skeletal anomalies. Clinical and radiological data were collected from 108 probands with short stature and mild skeletal anomalies. A customized skeletal dysplasia NGS panel was performed. Variants were classified using ACMG recommendations and Sherloc. Anthropometric measurements and skeletal anomalies were subsequently compared in those with or without an identified genetic defect. Heterozygous variants were identified in 21/108 probands (19.4%). Variants were most frequently identified in ACAN (n = 10) and IHH (n = 7) whilst one variant was detected in COL2A1, CREBBP, EXT1, and PTPN11. Statistically significant differences (P < 0.05) were observed for sitting height/height (SH/H) ratio, SH/H ratio standard deviation score (SDS), and the SH/H ratio SDS >1 in those with an identified variant compared to those without. A molecular defect was elucidated in a fifth of patients. Thus, the prevalence of mild forms of skeletal dysplasias is relatively high in individuals with short stature and mild skeletal anomalies, with variants in ACAN and IHH accounting for 81% of the cases. An elevated SH/H ratio appears to be associated with a greater probability in detecting a variant, but no other clinical or radiological feature has been found determinant to finding a genetic cause. Currently, we cannot perform extensive molecular studies in all short stature individuals so detailed clinical and radiological phenotyping may orientate which are the candidate patients to obtain worthwhile results. In addition, detailed phenotyping of probands and family members will often aid variant classification. Show less

The metabolically healthy obesity (MHO) phenotype is an important obesity subtype in which obesity is not accompanied by any metabolic comorbidity. However, the underlying molecular mechanisms remain elusive. In this study, a shotgun proteomics approach to identify circulating biomolecules and pathways associated with MHO was used. The subjects were 20 African-American women: 10 MHO cases and 10 metabolically abnormal individuals with obesity (MAO) controls. Serum proteins were detected and quantified using label-free proteomics. Differential expression of proteins between the two groups was analyzed, and the list of differentially expressed proteins was analyzed to determine enriched biological pathways. Twenty proteins were differentially expressed between MHO and controls. These proteins included: hemoglobin subunits (HBA1, P = 6.00 × 10(-18) ), haptoglobin-related protein (HPR, P = 1.2 × 10(-15) ), apolipoproteins (APOB-100, P = 1.50 × 10(-40) ; APOA4, P = 1.1 × 10(-14) ), retinol-binding protein 4 (RBP4, P = 7.1 × 10(-08) ), and CRP (P = 2.0 × 10(-04) ). MHO was associated with lower levels of proinflammatory and higher levels of anti-inflammatory biomarkers when compared with MAO. Pathway analysis showed enrichment of lipids and inflammatory pathways, including LXR/RXR and FXR/RXR activation, and acute phase response signaling. These findings suggested that protection from dysregulated inflammatory and lipid processes were primary molecular hallmarks of MHO. The candidate biomarkers (AHSG, RBP4, and APOA4) identified in this study are potential prognostic markers for MHO. Show less

During the process of reprogramming to induced pluripotent stem (iPS) cells, somatic cells switch from oxidative to glycolytic metabolism, a transition associated with profound mitochondrial reorganization. Neither the importance of mitochondrial remodelling for cell reprogramming, nor the molecular mechanisms controlling this process are well understood. Here, we show that an early wave of mitochondrial fragmentation occurs upon expression of reprogramming factors. Reprogramming-induced mitochondrial fission is associated with a minor decrease in mitochondrial mass but not with mitophagy. The pro-fission factor Drp1 is phosphorylated early in reprogramming, and its knockdown and inhibition impairs both mitochondrial fragmentation and generation of iPS cell colonies. Drp1 phosphorylation depends on Erk activation in early reprogramming, which occurs, at least in part, due to downregulation of the MAP kinase phosphatase Dusp6. Taken together, our data indicate that mitochondrial fission controlled by an Erk-Drp1 axis constitutes an early and necessary step in the reprogramming process to pluripotency. Show less

The R820W mutation in the MYBPC3 gene has been associated with the development of hypertrophic cardiomyopathy (HCM) in rag-doll cats, but had not been described in humans. To describe the phenotype associated with the R820W mutation identified in a human family. The R820W was identified by direct sequencing of the MYBPC3 gene in a 47 year old woman with HCM and left ventricular non-compaction (LVNC). Clinical and genetic studies of the R820W mutation were performed in her family. The index patient was homozygous for the mutation and had no additional mutations in the main sarcomeric genes (MYH7, TNNT2, TNNI3, and TPM1). She had HCM with LVNC and normal systolic function. One brother had died suddenly at age 43 years. Another brother diagnosed of LVNC with severe systolic dysfunction and a cardiac arrest was also homozygous for the mutation. One heterozygous 31 year old sister, and three heterozygous sons of the index (ages 14, 20 and 23 years old) were clinically unaffected. The father of the index was apparently healthy and her mother had atrial fibrillation and an electrocardiographic diagnosis of left ventricular hypertrophy at age 86 years. The R820W mutation in the MYBPC3 gene, previously associated with HCM in rag-doll cats, causes both HCM and LVNC in homozygous human carriers, with mild or null clinical expression in heterozygous carriers. Show less