BACKGROUND: Mitochondrial transfer is becoming recognized as an important immunomodulatory mechanism used by mesenchymal stem cells (MSCs) to influence immune cells. While effects on T cells and macrophages have been documented, the influence on B cells remains unexplored. This study investigates the modulation of B lymphocyte fate by MSC-mediated mitochondrial transfer. METHODS: MSCs labelled with MitoTracker dyes or derived from mito::mKate2 transgenic mice were co-cultured with splenocytes. Flow cytometry assessed mitochondrial transfer, reactive oxygen species (ROS) levels, apoptosis and mitophagy. Glucose uptake was measured using the 2-NBDG assay. RNA sequencing analysed gene expression changes in CD19+ mitochondria recipients and nonrecipients. Pathway analysis identified affected processes. In an LPS-induced inflammation model, mito::mKate2 MSCs were administered, and B cells from different organs were analysed for mitochondrial uptake and phenotypic changes. MSC-derived mitochondria were also isolated to confirm uptake by FACS-sorted CD19+ cells. RESULTS: MSCs transferred mitochondria to CD19+ cells, though less than to other immune cells. Transfer correlated with ROS levels and mitophagy induction. Mitochondria were preferentially acquired by activated B cells, as indicated by increased CD69 expression and glycolytic activity. Bidirectional transfer occurred, with immune cells exchanging dysfunctional mitochondria for functional ones. CD19+ recipients exhibited increased viability, proliferation and altered gene expression, with upregulated cell division genes and downregulated antigen presentation genes. In vivo, mitochondrial acquisition reduced B cell activation and inflammatory cytokine production. Pre-sorted B cells also acquired isolated mitochondria, exhibiting a similar anti-inflammatory phenotype. CONCLUSIONS: These findings highlight mitochondrial trafficking as a key MSC-immune cell interaction mechanism with immunomodulatory therapeutic potential.

• Klíčová slova
• B cell, immunoregulation, mesenchymal stem cell, metabolism, mitochondria,
• MeSH
• aktivace lymfocytů MeSH
• antigeny CD19 metabolismus   MeSH
• apoptóza MeSH
• B-lymfocyty * imunologie   fyziologie   metabolismus   MeSH
• CD antigeny MeSH
• diferenciační antigeny T-lymfocytů MeSH
• kokultivační techniky MeSH
• lektiny typu C MeSH
• mezenchymální kmenové buňky * fyziologie   MeSH
• mitochondrie * metabolismus   fyziologie   MeSH
• mitofagie MeSH
• myši transgenní MeSH
• myši MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• slezina cytologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antigeny CD19 MeSH
• CD antigeny MeSH
• CD69 antigen MeSH Prohlížeč
• diferenciační antigeny T-lymfocytů MeSH
• lektiny typu C MeSH
• reaktivní formy kyslíku MeSH

OBJECTIVES: Due to poor treatment adherence and lifestyle-based interventions, chronic hypertension is a dominant risk factor predisposing individuals to heart failure and malignant arrhythmias. We investigated the impact of the postnatal acclimation of hairless SHR to ambient temperature that is, for them, below thermoneutrality, on the electrical coupling protein connexin-43 (Cx43) and pro-fibrotic markers in both heart ventricles of male and female hairless SHR rats compared to the wild SHR. METHODS: Some 6-month-acclimated male and female hairless SHR as well as age- and sex-matched wild SHR were included and compared with the non-hypertensive Wistar strain. The left and right heart ventricles were examined for Cx43 topology, myocardial structure, and the histochemistry of capillaries. The protein levels of Cx43, relevant protein kinases, and extracellular matrix proteins (ECMs) were determined by immunoblotting. MMP-2 activity was assessed via zymography, and susceptibility to malignant arrhythmias was tested ex vivo. RESULTS: Cx43 and its phosphorylated variant pCx43368 were significantly reduced in the left heart ventricles of wild SHR males, while to a lesser extent in the hairless SHR. In contrast, these proteins were not significantly altered in the right heart ventricles of males or in both heart ventricles in females, regardless of the rat strain. Pro-arrhythmic Cx43 topology was detected in the left heart ventricle of wild SHR and to a lesser extent in hairless SHR males. TGFβ protein was significantly increased only in the left ventricle of the wild SHR males. MMP-2 activity was increased in the right ventricle but not in the left ventricles of both males and females, regardless of the rat strain. CONCLUSIONS: The findings indicate that the postnatal acclimation of hairless SHR to ambient temperature hampers the downregulation of Cx43 in the left heart ventricle compared to wild SHR males. The decline of Cx43 was much less pronounced in females and not observed in the right heart ventricles, regardless of the rat strain. It may impact the susceptibility of the heart to malignant arrhythmias.

• Klíčová slova
• arrhythmias, connexin43, females, hairless SHR, left and right heart ventricle, males,
• MeSH
• aklimatizace MeSH
• down regulace MeSH
• hypertenze * metabolismus   MeSH
• konexin 43 * metabolismus   genetika   MeSH
• krysa rodu Rattus MeSH
• potkani inbrední SHR * MeSH
• potkani Wistar MeSH
• srdeční arytmie * metabolismus   etiologie   MeSH
• srdeční komory * metabolismus   MeSH
• teplota * MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• Gja1 protein, rat MeSH Prohlížeč
• konexin 43 * MeSH