Downregulation of exosomal miR-192-5p and miR-204-5p in subjects with nonclassic apparent mineralocorticoid excess

Adipose Tissue Dysfunction and the Role of Adipocyte-Derived Extracellular Vesicles in Obesity and Metabolic Syndrome

Obesity is a major public health issue that is associated with metabolic diseases including diabetes mellitus type 2 and metabolic syndrome. This pathology leads to detrimental cardiovascular health and secondary effects, such as lipotoxicity, inflammation, and oxidative stress. Recently, extracellular vesicles (EVs) have been highlighted as novel players participating in human physiology and pathophysiology. In obesity, adipose tissue is related to the active shedding of adipocyte-derived extracellular vesicles (AdEVs). The current review explores and highlights the role of AdEVs and their cargo in obesity and metabolic syndrome. AdEVs are proposed to play an important role in obesity and its comorbidities. AdEVs are biological nanoparticles mainly shed by visceral and subcutaneous adipose tissue, acting in physiological and pathophysiological conditions, and also carrying different cargo biomolecules, such as RNA, microRNA (miRNA), proteins, and lipids, among others. RNA and miRNA have local and systemic effects affecting gene expression in target cell types via paracrine and endocrine actions. State of the art analyses identified some miRNAs, such as miR-222, miR-23b, miR-4429, miR-148b, and miR-4269, that could potentially affect cell pathways involved in obesity-related comorbidities, such as chronic inflammation and fibrosis. Similarly, AdEVs-proteins (RBP4, perilipin-A, FABP, mimecan, TGFBI) and AdEVs-lipids (sphingolipids) have been linked to the obesity pathophysiology. The current knowledge about AdEVs along with further research would support and reveal novel pathways, potential biomarkers, and therapeutic options in obesity.

Low Cortisone as a Novel Predictor of the Low-Renin Phenotype

A large proportion of patients with low-renin hypertension (LRH) correspond to primary aldosteronism (PA). However, some of these subjects have low to normal aldosterone. Since low renin is driven by excessive mineralocorticoids or glucocorticoids acting on mineralocorticoid receptors (MRs), we hypothesize that a low-cortisone condition, associated classically with 11βHSD2 deficiency, is a proxy of chronic MR activation by cortisol, which can also lead to low renin, elevated blood pressure, and renal and vascular alterations.

Objective

To evaluate low cortisone as a predictor of low renin activity and its association with parameters of kidney and vascular damage.

Methods

A cross-sectional study was carried out in 206 adult subjects. The subjects were classified according to low plasma renin activity (<1 ng/mL × hours) and low cortisone (<25th percentile).

Results

Plasma renin activity was associated with aldosterone (r = 0.36; P < .001) and cortisone (r = 0.22; P = .001). A binary logistic regression analysis showed that serum cortisone per ug/dL increase predicted the low-renin phenotype (OR 0.4, 95% CI 0.21-0.78). The receiver operating characteristic curves for cortisone showed an area under the curve of 0.6 to discriminate subjects with low renin activity from controls. The low-cortisone subjects showed higher albuminuria and PAI-1 and lower sodium excretion. The association study also showed that urinary cortisone was correlated with blood pressure and serum potassium (P < .05).

Conclusion

This is the first study showing that low cortisone is a predictor of a low-renin condition. Low cortisone also predicted surrogate markers of vascular and renal damage. Since the aldosterone to renin ratio is used in the screening of PA, low cortisone values should be considered additionally to avoid false positives in the aldosterone-renin ratio calculation.

Urinary extracellular vesicles carry valuable hints through mRNA for the understanding of endocrine hypertension

Urinary extracellular vesicles (uEVs), released from cells of the urogenital tract organs, carry precious information about originating tissues. The study of molecules transported through uEVs such as proteins, lipids and nucleic acids provides a deeper understanding of the function of the kidney, an organ involved in the pathogenesis of hypertension and a target of hypertension-mediated organ damage. Molecules derived from uEVs are often proposed for the study of disease pathophysiology or as possible disease diagnostic and prognostic biomarkers. Analysis of mRNA loading within uEVs may be a unique and readily obtainable way to assess gene expression patterns of renal cells, otherwise achievable only by an invasive biopsy procedure. Interestingly, the only few studies investigating transcriptomics of hypertension-related genes through the analysis of mRNA from uEVs are inherent to mineralocorticoid hypertension. More specifically, it has been observed that perturbation in human endocrine signalling through mineralcorticoid receptors (MR) activation parallels changes of mRNA transcripts in urine supernatant. Furthermore, an increased copy number of uEVs-extracted mRNA transcripts of the 11β-hydroxysteroid dehydrogenase type 2 (HSD11B2) gene were detected among subjects affected by apparent mineralocorticoid excess (AME), a hypertension-inducing autosomal recessive disorder due to a defective enzyme function. Moreover, by studying uEVs mRNA, it was observed that the renal sodium chloride cotransporter (NCC) gene expression is modulated under different conditions related to hypertension. Following this perspective, we illustrate here the state of the art and the possible future of uEVs transcriptomics towards a deeper knowledge of hypertension pathophysiology and ultimately more tailored investigational, diagnostic-prognostic approaches.

Apparent mineralocorticoid excess: comprehensive overview of molecular genetics

Apparent mineralocorticoid excess is an autosomal recessive form of monogenic disease characterized by juvenile resistant low-renin hypertension, marked hypokalemic alkalosis, low aldosterone levels, and high ratios of cortisol to cortisone metabolites. It is caused by defects in the HSD11B2 gene, encoding the enzyme 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2), which is primarily involved in the peripheral conversion of cortisol to cortisone. To date, over 50 deleterious HSD11B2 mutations have been identified worldwide. Multiple molecular mechanisms function in the lowering of 11β-HSD2 activity, including damaging protein stability, lowered affinity for the substrate and cofactor, and disrupting the dimer interface. Genetic polymorphism, environmental factors as well as epigenetic modifications may also offer an implicit explanation for the molecular pathogenesis of AME. A precise diagnosis depends on genetic testing, which allows for early and specific management to avoid the morbidity and mortality from target organ damage. In this review, we provide insights into the molecular genetics of classic and non-classic apparent mineralocorticoid excess and aim to offer a comprehensive overview of this monogenic disease.

Diagnostic and Therapeutic Roles of Extracellular Vesicles in Aging-Related Diseases

Aging shows a decline in overall physical function, and cellular senescence is the powerful catalyst leading to aging. Considering that aging will be accompanied with the emergence of various aging-related diseases, research on new antiaging drugs is still valuable. Extracellular vesicles (EVs), as tools for intercellular communication, are important components of the senescence-associated secretory phenotype (SASP), and they can play pathological roles in the process of cellular senescence. In addition, EVs are similar to their original cells in functions. Therefore, EVs derived from pathological tissues or body fluids may be closely related to the progression of diseases and become potential biomarkers, while those from healthy cells may have therapeutic effects. Moreover, EVs are satisfactory drug carriers. At present, numerous studies have supported the idea that engineered EVs could improve drug targeting ability and utilization efficiency. Here, we summarize the characteristics of EVs and cellular senescence and focus on the diagnostic and therapeutic potential of EVs in various aging-related diseases, including Alzheimer disease, osteoporosis, cardiovascular disease, diabetes mellitus and its complications, and skin aging.

Clinical, biochemical, and miRNA profile of subjects with positive screening of primary aldosteronism and nonclassic apparent mineralocorticoid excess

Primary aldosteronism (PA) and nonclassic apparent mineralocorticoid excess (NCAME) have been recognized as endocrine-related conditions having a broad clinical-biochemical spectrum, spanning from normotension to severe arterial hypertension (AHT). However, the coexistence of both phenotypes have not been reported to date.

AIM

To identify and characterize clinical and biochemical parameters of subjects with both PA and NCAME conditions (NCAME&PA) and study the miRNA cargo in their urinary extracellular vesicles as potential biomarkers for this novel condition.

METHODS

We performed a cross-sectional study of 206 Chilean adult subjects from a primary care cohort. We measured blood pressure (BP), cortisol (F), cortisone (E), aldosterone, plasma renin activity (PRA), microalbuminuria (MAC), plasma NGAL, MMP9, fractional-potassium-excretion (FEK). Subjects were classified as NCAME&PA, PA, NCAME, essential hypertensives (EH), or healthy controls (CTL). EV-miRNAs were quantified by Taqman-qPCR.

RESULTS

We found that 30.6% subjects had an abnormal endocrine phenotype: NCAME&PA (6.8%), PA (11.2%) or NCAME (12.6%), and the prevalence of AHT was 92.9%, 82.6%, and 65%, respectively. NCAME&PA subjects had both lower cortisone (p < 0.05) and lower PRA (p < 0.0001), higher FEK (p = 0.02) and higher MAC (p = 0.01) than EH or CTL. NCAME&PA subjects had also higher NGAL levels than CTL and PA (p < 0.05). Exosome miR-192, miR-133a and miR-21 expression decreased with phenotype severity and correlated with BP and PRA (p < 0.05).

CONCLUSION

We identified adult subjects with a combined condition of NCAME and PA associated with higher BP, increased renal and endothelial damage markers than control and EH. Additionally, we observed a differential expression of a specific miRNAs, suggesting a potential role of these miRNAs associated to this novel combined phenotype.

Development of Electrochemical Biosensor for miR204-Based Cancer Diagnosis

With increase in cancer burden worldwide and poor survival rates due to delayed diagnosis, it is pertinent to develop a device for early diagnosis. We report an electrochemical biosensor for quantification of miRNA-204 (miR-204) biomarker that is dysregulated in most of the cancers. The proposed methodology uses the gold nanoparticles-modified carbon screen-printed electrode for immobilization of single-stranded DNA probe against miR-204. Colloidal gold nanoparticles were synthesized using L-glutamic acid as reducing agent. Nanoparticles were characterized by UV-visible spectroscopy and transmission electron microscopy. Spherical gold nanoparticles were of 7-28 nm in size. Biosensor fabricated using these nanoparticles was characterized by cyclic voltammetry after spiking 0.1 fg/mL-0.1 µg/mL of miR-204 in fetal bovine serum. Response characteristics of the miR-204 biosensor displayed high sensitivity of 8.86 µA/µg/µL/cm² with wide detection range of 15.5 aM to 15.5 nM. The low detection limit makes it suitable for early diagnosis and screening of cancer.

Exosome-derived miR-127-5p promotes embryonic-like stem cells differentiation into pacemaker cell through NKx2.5 down-regulation

Available evidence suggests the involvement of microRNAs (miRNAs) in the pathological process of several diseases. Nonetheless, molecular mechanism underlying biological effects of miRNAs such as pacemaker exosome-derived miR-127-5p in embryonic-like stem cells (ESCs) differentiation into pacemaker cell is yet to be clarified. Through real time quantitative polymerase chain reaction (qPCR) or western blotting (WB) techniques, levels of miRNAs, miR-127-5p, and NKx2.5 expressions were quantitatively measured. Cellular differentiation (CD) was probed with flow cytometric (FC) and WB techniques. Prediction of miR-127-5p association with NKx2.5 was studied through bioinformatics tools before verification with luciferase assays. Promotion of ESCs differentiation to pacemaker through miR-127-5p was measured with qPCR and WB techniques. Through the same assaying methods, up-regulation of pace-making genes (Shox2, HCN4, Cx45, Tbx3 and Tbx18) expression was observed in Nkx2.5 knockdown group. However, Nkx2.5 expression was down-regulated during differentiation of pacemaker-like cells into ESCs. Furthermore, techniques (such as qPCR, WB, immunofluorescent staining and FC) were employed to demonstrate that overexpressed miR-127-5p could suppress NKx2.5 expression. Through NKx2.5 targeting, ESCs could be differentiated into pacemaker-like cells with miR-127-5p possibly serving as a crucial positive regulator. On the account of our findings, further researches are needed to unearth the possible underlying mechanism and role of exosome-derived miRNAs in cell signaling.

Aldosterone and renin concentrations were abnormally elevated in a cohort of normotensive pregnant women

BACKGROUND

During pregnancy, the renin-angiotensin-aldosterone system (RAAS) undergoes major changes to preserve normal blood pressure (BP) and placental blood flow and to ensure a good pregnancy outcome. Abnormal aldosterone-renin metabolism is a risk factor for arterial hypertension and cardiovascular risk, but its association with pathological conditions in pregnancy remains unknown. Moreover, potential biomarkers associated with these pathological conditions should be identified.

AIM

To study a cohort of normotensive pregnant women according to their serum aldosterone and plasma renin levels and assay their small extracellular vesicles (sEVs) and a specific protein cargo (LCN2, AT1R).

METHODS

A cohort of 54 normotensive pregnant women at term gestation was included. We determined the BP, serum aldosterone, and plasma renin concentrations. In a subgroup, we isolated their plasma sEVs and semiquantitated two EV proteins (AT1R and LCN2).

RESULTS

We set a normal range of aldosterone and renin based on the interquartile range. We identified 5/54 (9%) pregnant women with elevated aldosterone and low renin levels and 5/54 (9%) other pregnant women with low aldosterone and elevated renin levels. No differences were found in sEV-LCN2 or sEV-AT1R.

CONCLUSION

We found that 18% of normotensive pregnant women had either high aldosterone or high renin levels, suggesting a subclinical status similar to primary aldosteronism or hyperreninemia, respectively. Both could evolve to pathological conditions by affecting the maternal vascular and renal physiology and further the BP. sEVs and their specific cargo should be further studied to clarify their role as potential biomarkers of RAAS alterations in pregnant women.

Primary Aldosteronism, Aldosterone, and Extracellular Vesicles

Primary aldosteronism (PA) is an endocrine related condition leading to arterial hypertension due to inappropriately high and unregulated aldosterone concentration. Recently, a broad spectrum of PA has been recognized, which brings new challenges associated with early identification of this condition that affect renal epithelial and extrarenal tissues. Reports have shown the potential role of extracellular vesicles (EVs) and EV cargo as novel and complementary biomarkers in diagnosis and prognosis of PA. In vivo and in vitro studies have identified specific EV surface antigens, EV-proteins, and EV microRNAs that can be useful to develop novel diagnostic algorithms to detect, confirm, or follow up the PA. Moreover, the study of EVs in the field of PA provides further insight in the pathophysiological mechanism of the PA disease.

Serum Alpha-1-Acid Glycoprotein-1 and Urinary Extracellular Vesicle miR-21-5p as Potential Biomarkers of Primary Aldosteronism

Primary aldosteronism (PA) is the most common cause of secondary hypertension and reaches a prevalence of 6-10%. PA is an endocrine disorder, currently identified as a broad-spectrum phenotype, spanning from normotension to hypertension. In this regard, several studies have made advances in the identification of mediators and novel biomarkers of PA as specific proteins, miRNAs, and lately, extracellular vesicles (EVs) and their cargo.

Aim

To evaluate lipocalins LCN2 and AGP1, and specific urinary EV miR-21-5p and Let-7i-5p as novel biomarkers for PA.

Subjects and Methods

A cross-sectional study was performed in 41 adult subjects classified as normotensive controls (CTL), essential hypertensives (EH), and primary aldosteronism (PA) subjects, who were similar in gender, age, and BMI. Systolic (SBP) and diastolic (DBP) blood pressure, aldosterone, plasma renin activity (PRA), and aldosterone to renin ratio (ARR) were determined. Inflammatory parameters were defined as hs-C-reactive protein (hs-CRP), PAI-1, MMP9, IL6, LCN2, LCN2-MMP9, and AGP1. We isolated urinary EVs (uEVs) and measured two miRNA cargo miR-21-5p and Let-7i-5p by Taqman-qPCR. Statistical analyses as group comparisons were performed by Kruskall-Wallis, and discriminatory analyses by ROC curves were performed with SPSS v21 and Graphpad-Prism v9.

Results

PA and EH subjects have significantly higher SBP and DBP (p <0.05) than the control group. PA subjects have similar hs-CRP, PAI-1, IL-6, MMP9, LCN2, and LCN2-MMP9 but have higher levels of AGP1 (p <0.05) than the CTL&EH group. The concentration and size of uEVs and miRNA Let-7i-5p did not show any difference between groups. In PA, we found significantly lower levels of miR-21-5p than controls (p <0.05). AGP1 was associated with aldosterone, PRA, and ARR. ROC curves detected AUC for AGP1 of 0.90 (IC 95 [0.79 - 1.00], p <0.001), and combination of AGP1 and EV-miR-21-5p showed an AUC of 0.94 (IC 95 [0.85 - 1.00], p<0.001) to discriminate the PA condition from EH and controls.

Conclusion

Serum AGP1 protein was found to be increased, and miR-21-5p in uEVs was decreased in subjects classified as PA. Association of AGP1 with aldosterone, renin activity, and ARR, besides the high discriminatory capacity of AGP1 and uEV-miR-21-5p to identify the PA condition, place both as potential biomarkers of PA.

Role of microRNAs in Obesity-Related Kidney Disease

Obesity is a major global health problem and is associated with a significant risk of renal function decline. Obesity-related nephropathy, as one of the complications of obesity, is characterized by a structural and functional damage of the kidney and represents one of the important contributors to the morbidity and mortality worldwide. Despite increasing data linking hyperlipidemia and lipotoxicity to kidney injury, the apprehension of molecular mechanisms leading to a development of kidney damage is scarce. MicroRNAs (miRNAs) are endogenously produced small noncoding RNA molecules with an important function in post-transcriptional regulation of gene expression. miRNAs have been demonstrated to be important regulators of a vast array of physiological and pathological processes in many organs, kidney being one of them. In this review, we present an overview of miRNAs, focusing on their functional role in the pathogenesis of obesity-associated renal pathologies. We explain novel findings regarding miRNA-mediated signaling in obesity-related nephropathies and highlight advantages and future perspectives of the therapeutic application of miRNAs in renal diseases.

Novel metabolomic profile of subjects with non-classic apparent mineralocorticoid excess

Nonclassic apparent mineralocorticoid excess (NC-AME) is proposed as a novel clinical condition with a mild phenotypic spectrum that ranges from normotension to severe hypertension. This condition is mainly characterized by a high serum cortisol to cortisone ratio (F/E) and concomitant low cortisone (E), however further metabolic changes in NC-AME have not been studied. A cross-sectional study was performed in a primary-care cohort of 396 Chilean subjects, which were classified in two groups: NC-AME (n = 28) and healthy controls (n = 27). A discovery study based in untargeted metabolomics assay in serum samples from both groups was performed by UPLC-Q-TOF/MS. Global metabolomic variations were assayed by principal component analysis and further compared by orthogonal partial least-squares discriminant analysis (OPLS-DA). NC-AME subjects exhibited higher values of blood pressure, fractional excretion of potassium, and lower plasma renin activity and urinary sodium to potassium ratio. Metabolomic analyses showed 36 differentially regulated metabolites between NC-AME and control subjects. A ROC curve analyses identified eight metabolites with high discriminatory capacity between NC-AME and control subjects. Moreover, gamma-l-glutamyl-l-methionine sulfoxide and 5-sulfoxymethylfurfural, exhibited significant association with cortisone, which are potential biomarkers of NC-AME, however further assays should elucidate its biological role in setup and progression of this phenotype.

Proteomic Profile of Urinary Extracellular Vesicles Identifies AGP1 as a Potential Biomarker of Primary Aldosteronism

CONTEXT

Primary aldosteronism (PA) represents 6% to 10% of all essential hypertension patients and is diagnosed using the aldosterone-to-renin ratio (ARR) and confirmatory studies. The complexity of PA diagnosis encourages the identification of novel PA biomarkers. Urinary extracellular vesicles (uEVs) are a potential source of biomarkers, considering that their cargo reflects the content of the parent cell.

OBJECTIVE

We aimed to evaluate the proteome of uEVs from PA patients and identify potential biomarker candidates for PA.

METHODS

Second morning spot urine was collected from healthy controls (n = 8) and PA patients (n = 7). The uEVs were isolated by ultracentrifugation and characterized. Proteomic analysis on uEVs was performed using LC-MS Orbitrap.

RESULTS

Isolated uEVs carried extracellular vesicle markers, showed a round shape and sizes between 50 and 150 nm. The concentration of uEVs showed a direct correlation with urinary creatinine (r = 0.6357; P = 0.0128). The uEV size mean (167 ± 6 vs 183 ± 4nm) and mode (137 ± 7 vs 171 ± 11nm) was significantly smaller in PA patients than in control subjects, but similar in concentration. Proteomic analysis of uEVs from PA patients identified an upregulation of alpha-1-acid glycoprotein 1 (AGP1) in PA uEVs, which was confirmed using immunoblot. A receiver operating characteristic curve analysis showed an area under the curve of 0.92 (0.82 to 1; P = 0.0055).

CONCLUSION

Proteomic and further immunoblot analyses of uEVs highlights AGP1 as potential biomarker for PA.

Detection of Urinary Exosomal HSD11B2 mRNA Expression: A Useful Novel Tool for the Diagnostic Approach of Dysfunctional 11β-HSD2-Related Hypertension

OBJECTIVE

Apparent mineralocorticoid excess (AME) is an autosomal recessive disorder caused by the 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) enzyme deficiency, traditionally assessed by measuring either the urinary cortisol metabolites ratio (tetrahydrocortisol+allotetrahydrocortisol/tetrahydrocortisone, THF+5αTHF/THE) or the urinary cortisol/cortisone (F/E) ratio. Exosomal mRNA is an emerging diagnostic tool due to its stability in body fluids and its biological regulatory function. It is unknown whether urinary exosomal HSD11B2 mRNA is related to steroid ratio or the HSD11B2 662 C>G genotype (corresponding to a 221 A>G substitution) in patients with AME and essential hypertension (EH).

AIM OF THE STUDY

To detect and quantify HSD11B2 mRNA from urinary exosomes in samples from family members affected by AME and EH, and to evaluate the relationship between exosomal HSD11B2 mRNA, steroid ratio, 662C>G genotype, and hypertension.

METHODS

In this observational case-control study, urinary steroid ratios and biochemical parameters were measured. Urinary exosomes were extracted from urine and exosomal HSD11B2 mRNA was quantified by Droplet Digital PCR (ddPCR). B2M (β-2 microglobulin) gene was selected as the reference housekeeping gene.

RESULTS

Among family members affected by AME, exosomal urinary HSD11B2 mRNA expression was strictly related to genotypes. The two homozygous mutant probands showed the highest HSD11B2 mRNA levels (median 169, range 118-220 copies/µl) that progressively decreased in 221 AG heterozygous with hypertension (108, range 92-124 copies/µl), 221 AG heterozygous normotensives (23.35, range 8-38.7 copies/µl), and wild-type 221 AA subjects (5.5, range 4.5-14 copies/µl). Heterozygous hypertensive subjects had more HSD11B2 mRNA than heterozygous normotensive subjects. The F/E urinary ratio correlated with HSD11B2 mRNA copy number (p < 0.05); HSD11B2 mRNA strongly decreased while THF+5αTHF/THE increased in the two probands after therapy. In the AME family, HSD11B2 copy number correlated with both F/E and THF+5αTHF/THE ratios, whereas in EH patients, a high F/E ratio reflected a reduced HSD11B2 mRNA expression.

CONCLUSIONS

HSD11B2 mRNA is detectable and quantifiable in urinary exosomes; its expression varies according to the 662 C>G genotype with the highest levels in homozygous mutant subjects. The HSD11B2 mRNA overexpression in AME could be due to a compensatory mechanism of the enzyme impairment. Exosomal mRNA is a useful tool to investigate HSD11B2 dysregulation in hypertension.

Overview of Monogenic Forms of Hypertension Combined With Hypokalemia

Hypertension is an important risk factor in many conditions and creates a heavy burden of disease and mortality globally. Polygenic hypertension is the most common form; however, it is increasingly recognized that monogenic hypertension is not rare, especially in patients with electrolyte disorders. Single genetic alterations are associated with plasma volume expansion and catecholamines/sympathetic excess with simultaneously increased potassium excretion in the urine and potassium intracellular shift. Early-onset refractory hypertension and profound hypokalemia are characteristics of monogenic hypertension. However, accumulated evidence shows the existence of phenotypic heterogeneity in monogenic hypertension meaning that, even for mild symptoms, clinicians cannot easily exclude the possibility of monogenic hypertension. Genetic, epigenetic and non-genetic factors are all possible mechanisms influencing phenotypic diversity. Genetic sequencing is a precise and efficient method that can broaden the mutant gene spectrum of the disease and is very helpful for understanding the pathophysiology of monogenic hypertension. Genetic sequencing, along with biochemical tests and imaging modalities, is essential for the early diagnosis and targeted management of monogenic hypertension to avoid long-term catastrophic complications.