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Endolymph, a high K+/low Na+ fluid, participates in mechano-electrical transduction in inner ear. Molecular mechanisms controlling endolymph ion homeostasis remain elusive, hampered by the lack of appropriate cellular models. We established an inner ear cell line by targeted oncogenesis. The expression of SV40T antigen was driven by the proximal promoter of the human mineralocorti-cold receptor (MR) gene, a receptor expressed in the inner ear. The EC5v cell line, microdissected from the semicircular canal, grew as a monolayer of immortalized epithelial cells forming domes. EC5v cells exhibited on filters of high transepithelial resistance and promoted K+ secretion and Na+ absorption. Functional MR and the 11β-hydroxysteroid dehydrogenase type 2, a key enzyme responsible for MR selectivity were identified. Expression of the epithelial sodium channel and serum glucocorticoid-regulated kinase 1 was shown to be up-regulated by aldosterone, indicating that EC5v represents a novel corticosteroid-sensitive cell line. Ionic measurements and 86Rb transport assays revealed an apical secretion of K+ at least in part through the IsK/KvLQT1 potassium channel under standard culture conditions. However, when cells were apically exposed to high K+/low Na+ fluid, mimicking endolymph exposure, IsK/KvLQT1 actually functioned as a strict apical to basolateral K+ channel inhibited by clofilium. Quantitative reverse transcriptase-PCR further demonstrated that expression of KvLQT1 but not of IsK was down-regulated by high K+ concentration. This first vestibular cellular model thus constitutes a valuable system to further investigate the molecular mechanisms controlling ionic transports in the inner ear and the pathophysiological consequences of their dysfunctions in vertigo and hearing loss. [ABSTRACT FROM AUTHOR]

Introduction: Acute kidney injury (AKI) and myocardial injury (MI) are severe conditions in patients with severe burn injury, and combination of both is even worst and is called the cardiorenal syndrome (CRS). Identifying a distinct cardiorenal phenotype could significantly enhance the management of these patients. Galectin-3 (Gal3) and soluble CD146 (sCD146) are biomarkers for renal and cardiac injuries. This study aims to assess the occurrence and reliability of these biomarkers in recognizing CRS in individuals who have been severely burn., Methods: This study is a single-center prospective proof-of-concept study involving patients with severe burn injuries. Plasma samples for Gal3 and sCD146 measurements were collected daily during the initial 7 days following admission. CRS was defined after 24 h of admission by the association of AKI stage 1 or more (KDIGO definition) and MI defined on high sensitive troponin (hsTnT) (variation >20% baseline value or absolute value >40 ng/mL)., Results: Forty patients met the inclusion criteria and were included in this study. Thirty-eight patients had CRS. The pooled values of Gal3 or combination of Gal3 and sCD146 values following 7 days after admission were associated with CRS with an odds ratio (OR) of 1.145 (95% CI: 1.081-1.211), p < 0.001, and 1.147 (95% CI: 1.085-1.212), p < 0.001, respectively. Gal3 values at admission (D0) had a predictive performance for CRS with an AUC of 0.78 (95% CI: 0.63-0.93), and this performance improved when using the combination of Gal3 and sCD146 values at admission (D0), with an AUC of 0.81 (95% CI: 0.66-0.96). Gal3 levels during the first 7 days were associated with patients experiencing AKI and no MI, with an OR of 1.129 (95% CI: 1.065-1.195), p < 0.001, and MI without AKI with an OR of 1.095 (95% CI: 1.037-1.167), p < 0.001. sCD146 alone was not associated with AKI without MI or MI without AKI and was poorly associated with CRS., Conclusion: In severely burned patients, CRS is a frequent and severe condition. Gal3 values during the first 7 days following admission were associated with CRS. The use of sCD146 with Gal3 improved prediction performance for CRS identification. The use of such biomarkers to identify CRS is important and needs to be confirmed in other studies., (© 2024 The Author(s). Published by S. Karger AG, Basel.)

The fundamental role of cell adhesion molecules in mediating various biological processes as angiogenesis has been well-documented. CD146, an adhesion molecule of the immunoglobulin superfamily, and its soluble form, constitute major players in both physiological and pathological angiogenesis. A growing body of evidence shows soluble CD146 to be significantly elevated in the serum or interstitial fluid of patients with pathologies related to deregulated angiogenesis, as autoimmune diseases, obstetric and ocular pathologies, and cancers. To block the undesirable effects of this molecule, therapeutic antibodies have been developed. Herein, we review the multifaceted functions of CD146 in physiological and pathological angiogenesis and summarize the interest of using monoclonal antibodies for therapeutic purposes.

CD146 is a cell adhesion molecule expressed on endothelial cells, as well as on other cells such as mesenchymal stem cells and Th17 lymphocytes. This protein also exists in a soluble form, whereby it can be detected in biological fluids, including the serum or the cerebrospinal fluid (CSF). Some studies have highlighted the significance of CD146 and its soluble form in angiogenesis and inflammation, having been shown to contribute to the pathogenesis of many inflammatory autoimmune diseases, such as systemic sclerosis, mellitus diabetes, rheumatoid arthritis, inflammatory bowel diseases, and multiple sclerosis. In this review, we will focus on how CD146 and sCD146 contribute to the pathogenesis of the aforementioned autoimmune diseases and discuss the relevance of considering it as a biomarker in these pathologies.

The objective of the study was to use CD146 mRNA to predict the evolution of patients with non-metastatic clear cell renal cell carcinoma (M0 ccRCC) towards metastatic disease, and to use soluble CD146 (sCD146) to anticipate relapses on reference treatments by sunitinib or bevacizumab in patients with metastatic ccRCC (M1). Methods : A retrospective cohort of M0 patients was used to determine the prognostic role of intra-tumor CD146 mRNA. Prospective multi-center trials were used to define plasmatic sCD146 as a predictive marker of sunitinib or bevacizumab efficacy for M1 patients. Results : High tumor levels of CD146 mRNA were linked to shorter disease-free survival (DFS) and overall survival (OS). ccRCC patients from prospective cohorts with plasmatic sCD146 variation <120% following the first cycle of sunitinib treatment had a longer progression-free survival (PFS) and OS. The plasmatic sCD146 variation did not correlate with PFS or OS for the bevacizumab-based treatment. In vitro, resistant cells to sunitinib expressed high levels of CD146 mRNA and protein in comparison to sensitive cells. Moreover, recombinant CD146 protected cells from the sunitinib-dependent decrease of cell viability. Conclusion : CD146/sCD146 produced by tumor cells is a relevant biological marker of ccRCC aggressiveness and relapse on sunitinib treatment., Competing Interests: Competing Interests: The authors have declared that no competing interest exists.

CD146 is an adhesion molecule present on many tumors (melanoma, kidney, pancreas, breast, ...). In addition, it has been shown to be expressed on vascular endothelial and smooth muscle cells. Generating an antibody able to specifically recognize CD146 in cancer cells (designated as tumor CD146), but not in normal cells, would thus be of major interest for targeting tumor CD146 without affecting the vascular system. We thus generated antibodies against the extracellular domain of the molecule produced in cancer cells and selected an antibody that specifically recognizes tumor CD146. This antibody (TsCD146 mAb) was able to detect CD146-positive tumors in human biopsies and in vivo , by PET imaging, in a murine xenograft model. In addition, TsCD146 mAb antibody was able to specifically detect CD146-positive cancer microparticles in the plasma of patients. TsCD146 mAb displayed also therapeutic effects since it was able to reduce the growth of human CD146-positive cancer cells xenografted in nude mice. This effect was due to a decrease in the proliferation and an increase in the apoptosis of CD146-positive cancer cells after TsCD146-mediated internalization of the cell surface CD146. Thus, TsCD146 mAb could be of major interest for diagnostic and therapeutic strategies against CD146-positive tumors in a context of personalized medicine., Competing Interests: CONFLICTS OF INTEREST The authors have no conflicts of interest to disclose.

Rationale: CD146, a transmembrane immunoglobulin mainly expressed at the intercellular junction of endothelial cells, is involved in cell-cell cohesion, paracellular permeability, monocyte transmigration and angiogenesis. CD146 exists as 2 isoforms, short (sh) and long (lg), but which isoform is involved remains undefined., Objective: The recently described role of CD146 in angiogenesis prompted us to investigate which isoform was involved in this process in human late endothelial progenitors (EPCs), with the objective of increasing their proangiogenic potential., Methods and Results: Immunofluorescence experiments showed that, in subconfluent EPCs, shCD146 was localized in the nucleus and at the migrating edges of the membrane, whereas lgCD146 was intracellular. In confluent cells, shCD146 was redistributed at the apical membrane and lgCD146 was directed toward the junction. In contrast to lgCD146, shCD146 was overexpressed in EPCs as compared to mature endothelial cells and upregulated by vascular endothelial growth factor and SDF-1 (stromal cell-derived factor 1). Study of the properties of both isoforms in vitro provided evidence that shCD146 was involved in EPC adhesion to activated endothelium, migration, and proliferation, with a paracrine secretion of interleukin-8 or angiopoietin 2, whereas lgCD146 was implicated in stabilization of capillary-like structures in Matrigel and transendothelial permeability. In an animal model of hindlimb ischemia, transplantation of shCD146-modified EPCs selectively promoted both EPC engraftment and blood flow., Conclusions: Altogether, these findings establish that CD146 isoforms display distinct functions in vessels regeneration. Selective improvement of therapeutic angiogenesis by shCD146 overexpression suggests a potential interest of shCD146-transduced EPCs for the treatment of peripheral ischemic disease.

Effects of aldosterone on its target cells have long been considered to be mediated exclusively through the genomic pathway; however, evidence has been provided for rapid effects of the hormone that may involve nongenomic mechanisms. Whether an interaction exists between these two signaling pathways is not yet established. In this study, the authors show that aldosterone triggers both early nongenomic and late genomic increase in sodium transport in the RCCD(2) rat cortical collecting duct cell line. In these cells, the early (up to 2.5 h) aldosterone-induced increase in short-circuit current (Isc) is not blocked by the mineralocorticoid receptor (MR) antagonist RU26752, it does not require mRNA or protein synthesis, and it involves the PKCalpha signaling pathway. In addition, this early response is reproduced by aldosterone-BSA, which acts at the cell surface and presumably does not enter the cells (aldo-BSA is unable to trigger the late response). The authors also show that MR is rapidly phosphorylated on serine and threonine residues by aldosterone or aldosterone-BSA. In contrast, the late (4 to 24 h) aldosterone-induced increase in ion transport occurs through activation of the MR and requires mRNA and protein synthesis. Interestingly, nongenomic and genomic aldosterone actions appear to be interdependent. Blocking the PKCalpha pathway results in the inhibition of the late genomic response to aldosterone, as demonstrated by the suppression of aldosterone-induced increase in MR transactivation activity, alpha1 Na(+)/K(+)/ATPase mRNA, and Isc. These data suggest cross-talk between the nongenomic and genomic responses to aldosterone in renal cells and suggest that the aldosterone-MR mediated increase in mRNA/protein synthesis and ion transport depends, at least in part, upon PKCalpha activation. E-mail: marcel.blot-chabaud@pharmacie.univ-mrs.fr

The regulation of plasma membrane Na(+)-K(+)-ATPases (NKA) expression by aldosterone and arginin vasopressin (AVP) in the cortical collecting duct (CCD) has been examined in a new rat CCD cell line, designated as RCCD(2). This cell line has maintained many characteristics of the CCD-in particular, the expression of the mineralocorticoid receptor. Mineralocorticoid receptor is expressed at the protein level and binds (3)H-aldosterone (approximately 15 to 20 fmol/mg protein). Short-circuit current (Isc) experiments showed approximately a twofold increase in Isc associated with a decrease in transepithelial resistance when cells were treated with aldosterone concentrations as low as 10(-9) M. This effect on Isc was significant 2 h after aldosterone addition and was still present after 24 h. It was accompanied by an increase in the amount of mRNA encoding for the alpha subunit of the epithelial sodium channel (sixfold) and the alpha1 subunit of NKA (fourfold) after 24 h of hormone treatment. In addition, mRNA expression of the serum- and glucocorticoid-induced kinase (Sgk) was increased by 10(-9) M aldosterone treatment as early as 45 min after hormone addition. As had already been documented in native CCD obtained by microdissection, incubation of RCCD(2) cells for 24 h with aldosterone resulted in the constitution of a latent pool of NKA that could be rapidly recruited by AVP (15 min). NKA biotinylation experiments and preparation of membrane fractions show that this latent pool of NKA is present in the intracellular compartment of the cells and is recruited by AVP in the basolateral membrane through a translocation process. This mechanism is accompanied by dephosphorylation of the alpha(1) catalytic subunit of NKA.