The role of TRPC6 calcium channels and P2 purinergic receptors in podocyte mechanical and metabolic sensing

Podocyte calcium (Ca2+) signaling plays important roles in the (patho)physiology of the glomerular filtration barrier. Overactivation of podocyte transient receptor potential canonical (TRPC) channels including TRPC6 and purinergic signaling via P2 receptors that are known mechanosensors can increase podocyte intracellular Ca2+ levels ([Ca2+]i) and cause cell injury, proteinuria and glomerular disease including in diabetes. However, important mechanistic details of the trigger and activation of these pathways in vivo in the intact glomerular environment are lacking. Here we show direct visual evidence that podocytes can sense mechanical overload (increased glomerular capillary pressure) and metabolic alterations (increased plasma glucose) via TRPC6 and purinergic receptors including P2Y2. Multiphoton microscopy of podocyte [Ca2+]i was performed in vivo using wild-type and TRPC6 or P2Y2 knockout (KO) mice expressing the calcium reporter GCaMP3/5 only in podocytes and in vitro using freshly dissected microperfused glomeruli. Single-nephron intra-glomerular capillary pressure elevations induced by obstructing the efferent arteriole lumen with laser-induced microthrombus in vivo and by a micropipette in vitro triggered >2-fold increases in podocyte [Ca2+]i. These responses were blocked in TRPC6 and P2Y2 KO mice. Acute elevations of plasma glucose caused >4-fold increases in podocyte [Ca2+]i that were abolished by pharmacological inhibition of TRPC6 or P2 receptors using SAR7334 or suramin treatment, respectively. This study established the role of Ca2+ signaling via TRPC6 channels and P2 receptors in mechanical and metabolic sensing of podocytes in vivo, which are promising therapeutic targets in conditions with high intra-glomerular capillary pressure and plasma glucose, such as diabetic and hypertensive nephropathy. © 2021 The Author(s)

A new view of macula densa cell microanatomy

Although macula densa (MD) cells are chief regulatory cells in the nephron with unique microanatomical features, they have been difficult to study in full detail due to their inaccessibility and limitations in earlier microscopy techniques. The present study used a new mouse model with a comprehensive imaging approach to visualize so far unexplored microanatomical features of MD cells, their regulation, and functional relevance. MD-GFP mice with conditional and partial induction of green fluorescent protein (GFP) expression, which specifically and intensely illuminated only single MD cells, were used with fluorescence microscopy of fixed tissue and live MD cells in vitro and in vivo with complementary electron microscopy of the rat, rabbit, and human kidney. An elaborate network of major and minor cell processes, here named maculapodia, were found at the cell base, projecting toward other MD cells and the glomerular vascular pole. The extent of maculapodia showed upregulation by low dietary salt intake and the female sex. Time-lapse imaging of maculapodia revealed highly dynamic features including rapid outgrowth and an extensive vesicular transport system. Electron microscopy of rat, rabbit, and human kidneys and three-dimensional volume reconstruction in optically cleared whole-mount MD-GFP mouse kidneys further confirmed the presence and projections of maculapodia into the extraglomerular mesangium and afferent and efferent arterioles. The newly identified dynamic and secretory features of MD cells suggest the presence of novel functional and molecular pathways of cell-to-cell communication in the juxtaglomerular apparatus between MD cells and between MD and other target cells.NEW & NOTEWORTHY This study illuminated a physiologically regulated dense network of basal cell major and minor processes (maculapodia) in macula densa (MD) cells. The newly identified dynamic and secretory features of these microanatomical structures suggest the presence of novel functional and molecular pathways of cell-to-cell communication in the juxtaglomerular apparatus between MD and other target cells. Detailed characterization of the function and molecular details of MD cell intercellular communications and their role in physiology and disease warrant further studies

Night shift work and stomach cancer risk in the MCC-Spain study

OBJECTIVES: Night shift work has been classified as a probable human carcinogen by the International Agency for Research on Cancer, based on experimental studies and limited evidence on human breast cancer risk. Evidence at other cancer sites is scarce. We evaluated the association between night shift work and stomach cancer risk in a population-based case-control study. METHODS: A total of 374 incident stomach adenocarcinoma cases and 2481 population controls were included from the MCC-Spain study. Detailed data on lifetime night shift work were collected including permanent and rotating shifts, and their cumulative duration (years). Adjusted unconditional logistic regression models were used in analysis. RESULTS: A total of 25.7% of cases and 22.5% of controls reported ever being a night shift worker. There was a weak positive, non-significant association between ever having had worked for at least 1?year in permanent night shifts and stomach cancer risk compared to never having worked night shifts (OR=1.2, 95% CI 0.9 to 1.8). However, there was an inverse 'U' shaped relationship with cumulative duration of permanent night shifts, with the highest risk observed in the intermediate duration category (OR 10-20?years=2.0, 95% CI 1.1 to 3.6) (p for trend=0.19). There was no association with ever having had worked in rotating night shifts (OR=0.9, 95% CI 0.6 to 1.2) and no trend according to cumulative duration (p for trend=0.68). CONCLUSION: We found no clear evidence concerning an association between night shift work and stomach cancer ris

B-natriuretikus peptid meghatározás jelentősége gyermekkori szívbetegségekben = Utility of B-type natriuretic peptide in children

A natriuretikus peptid mérés kamra diszfunkciót jelző szerepe már bizonyítást nyert, felnőttkori alkalmazásáról már hazánkban is beszámoltak. Célunk volt a gyermekkori BNP vizsgálataink klinikai szerepének felmérése, melyet 107 gyermekben történt 157 mérés adatai alapján értékeltünk, szisztémás jobb kamra, illetve bal kamra funkció megítélésére. Célunk volt továbbá a BNP és az MRI vizsgálattal és echocardiographiás módszerrel mért kamra funkció paraméterek összevetése. Betegek: életkor 4 hó-20 év, átl.: 12,5 év. Betegcsoportok: I. Senning műtött nagyértranspositiós, II. dilatatív és III. hypertrophiás cardiomyopathiás és IV. aorta insufficientiában szenvedő betegek. Módszerek: BNP mérés elektrokemilumineszcenciás (Elecsys-10 Roche) módszerrel, a kamra volumeneket és EF értéket MRI volumetriás (MASS–Medis software) meghatározással értékeltük, echocardiographiával a standard M-mode mérések mellett totál ejectiós izovolumetriás (TEI) index indexet határoztunk meg. Eredmények:a BNP érték szignifikánsan magasabb volt az összes betegségcsoportban a normál értékhez képest: I. csoport: 318 ± 285 pg/ml, p < 0,01, II. csoport: 7262 ± 10970 pg/ml, p < 0,001, III. csoport: 1558 ± 2765 pg/ml, p < 0,01, IV. csoport: 1076 ± 2791 pg/ml, p < 0,001, vs 58 ± 31 pg/ml. A BNP korrelált az MRI JK EF értékkel (r: –0,51, p < 0,05) és TEI index-szel (0,43 ± 0,18) p < 0,05. Sebészi vagy 3 hetes gyógyszeres kezelés után a BNP szignifikáns csökkenését igazoltuk. 4 beteg halt meg a vizsgálati időszak alatt, mindegyiknek az adott betegségcsoportban a legmagasabb értékű volt a BNP szintje. Konklúzió: A BNP mérés egy hasznos, prognosztikai értékű biomarker a kamra funkció monitorizálásában gyermekekben. A BNP tükrözi a szisztémás jobb kamra funkció károsodását Senning műtött nagyértranspositiós betegekben, ahol a komplex jobbkamrai geometria miatt különösen nehéz a jobb kamra funkció megítélése. Emiatt ajánljuk a BNP sorozatos mérését ezen betegcsoportokban. Serum brain natriuretic peptide (BNP) has been reported to indicate ventricular dysfunction, however, in children it has not been studied yet in our country. Purpose: 157 BNP tests were performed in 107 children, on the one hand, to evaluate, its clinical value, to assess LV or sytemic RV function in patients with transposition of great arteries after Senning operation, on the other hand, to prove the relation between BNP, MRI and echocardiographic ventricular function parameters. Patients’ age: 4 months-20 years, mean 12.5 yrs. Group I: Senning patients, Groups II and III: patients with dilated or hypertrophic cardiomyopathy, Group IV: patients with aortic insufficiency. Methods: BNP was determined using the electrochemiluminesce method (Elycsys-10 Roche). During the functional MRI Mass – Medis software RV LV EF, enddiastolic, endsystolic volumes were calculated. Echo M-mode, TEI index were calculated. Results: BNPs were significantly as higher compared to normal in each group of patients. Group I: 318 ± 285 pg/ml, p < 0.01, Group II: 7262 ± 10970 pg/ml, p < 0.01, Group III: 1558 ± 2765 pg/ml, p < 0.01, Group IV: 1076 ± 2791 pg/ml, p < 0.00l, vs 58 ± 31 pg/ml. BNP were negatively correlated with MRI RV EF (r: –0.51, p < 0.05) and showed good correlation with TEI index (0.43 ± 0.18, p < 0.05). After 3 weeks of medical or surgical treatment BNP decreased significantly. 4 patients died during the follow-up period, these had the highest BNP levels in each patients group. Conclusions: BNP is a useful, prognostically valuable method in children to monitor ventricular function. BNP levels reflect the severity of the impairment of systemic RV function in Senning patients in whom a complex RV geometry is present causing the assessment of RV function more difficult, so we recommend BNP measurements as a longitudinal test in this patient group

Essential role and therapeutic targeting of the glomerular endothelial glycocalyx in lupus nephritis

Lupus nephritis (LN) is a major organ complication and cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE). There is an unmet medical need for developing more efficient and specific, mechanism-based therapies, which depends on improved understanding of the underlying LN pathogenesis. Here we present direct visual evidence from high-power intravital imaging of the local kidney tissue microenvironment in mouse models showing that activated memory T cells originated in immune organs and the LN-specific robust accumulation of the glomerular endothelial glycocalyx played central roles in LN development. The glomerular homing of T cells was mediated via the direct binding of their CD44 to the hyaluronic acid (HA) component of the endothelial glycocalyx, and glycocalyx-degrading enzymes efficiently disrupted homing. Short-course treatment with either hyaluronidase or heparinase III provided long-term organ protection as evidenced by vastly improved albuminuria and survival rate. This glycocalyx/HA/memory T cell interaction is present in multiple SLE-affected organs and may be therapeutically targeted for SLE complications, including LN

ORAI1 Activates Proliferation of Lymphatic Endothelial Cells in Response to Laminar Flow Through Krüppel-Like Factors 2 and 4

RationaleLymphatic vessels function to drain interstitial fluid from a variety of tissues. Although shear stress generated by fluid flow is known to trigger lymphatic expansion and remodeling, the molecular basis underlying flow-induced lymphatic growth is unknown.ObjectiveWe aimed to gain a better understanding of the mechanism by which laminar shear stress activates lymphatic proliferation.Methods and resultsPrimary endothelial cells from dermal blood and lymphatic vessels (blood vascular endothelial cells and lymphatic endothelial cells [LECs]) were exposed to low-rate steady laminar flow. Shear stress-induced molecular and cellular responses were defined and verified using various mutant mouse models. Steady laminar flow induced the classic shear stress responses commonly in blood vascular endothelial cells and LECs. Surprisingly, however, only LECs showed enhanced cell proliferation by regulating the vascular endothelial growth factor (VEGF)-A, VEGF-C, FGFR3, and p57/CDKN1C genes. As an early signal mediator, ORAI1, a pore subunit of the calcium release-activated calcium channel, was identified to induce the shear stress phenotypes and cell proliferation in LECs responding to the fluid flow. Mechanistically, ORAI1 induced upregulation of Krüppel-like factor (KLF)-2 and KLF4 in the flow-activated LECs, and the 2 KLF proteins cooperate to regulate VEGF-A, VEGF-C, FGFR3, and p57 by binding to the regulatory regions of the genes. Consistently, freshly isolated LECs from Orai1 knockout embryos displayed reduced expression of KLF2, KLF4, VEGF-A, VEGF-C, and FGFR3 and elevated expression of p57. Accordingly, mouse embryos deficient in Orai1, Klf2, or Klf4 showed a significantly reduced lymphatic density and impaired lymphatic development.ConclusionsOur study identified a molecular mechanism for laminar flow-activated LEC proliferation

Night shift work and stomach cancer risk in the MCC-Spain study

OBJECTIVES: Night shift work has been classified as a probable human carcinogen by the International Agency for Research on Cancer, based on experimental studies and limited evidence on human breast cancer risk. Evidence at other cancer sites is scarce. We evaluated the association between night shift work and stomach cancer risk in a population-based case-control study. METHODS: A total of 374 incident stomach adenocarcinoma cases and 2481 population controls were included from the MCC-Spain study. Detailed data on lifetime night shift work were collected including permanent and rotating shifts, and their cumulative duration (years). Adjusted unconditional logistic regression models were used in analysis. RESULTS: A total of 25.7% of cases and 22.5% of controls reported ever being a night shift worker. There was a weak positive, non-significant association between ever having had worked for at least 1 year in permanent night shifts and stomach cancer risk compared to never having worked night shifts (OR=1.2, 95% CI 0.9 to 1.8). However, there was an inverse 'U' shaped relationship with cumulative duration of permanent night shifts, with the highest risk observed in the intermediate duration category (OR 10-20 years=2.0, 95% CI 1.1 to 3.6) (p for trend=0.19). There was no association with ever having had worked in rotating night shifts (OR=0.9, 95% CI 0.6 to 1.2) and no trend according to cumulative duration (p for trend=0.68). CONCLUSION: We found no clear evidence concerning an association between night shift work and stomach cancer risk

Night shift work and stomach cancer risk in the MCC-Spain study

OBJECTIVES: Night shift work has been classified as a probable human carcinogen by the International Agency for Research on Cancer, based on experimental studies and limited evidence on human breast cancer risk. Evidence at other cancer sites is scarce. We evaluated the association between night shift work and stomach cancer risk in a population-based case-control study. METHODS: A total of 374 incident stomach adenocarcinoma cases and 2481 population controls were included from the MCC-Spain study. Detailed data on lifetime night shift work were collected including permanent and rotating shifts, and their cumulative duration (years). Adjusted unconditional logistic regression models were used in analysis. RESULTS: A total of 25.7% of cases and 22.5% of controls reported ever being a night shift worker. There was a weak positive, non-significant association between ever having had worked for at least 1 year in permanent night shifts and stomach cancer risk compared to never having worked night shifts (OR=1.2, 95% CI 0.9 to 1.8). However, there was an inverse 'U' shaped relationship with cumulative duration of permanent night shifts, with the highest risk observed in the intermediate duration category (OR 10-20 years=2.0, 95% CI 1.1 to 3.6) (p for trend=0.19). There was no association with ever having had worked in rotating night shifts (OR=0.9, 95% CI 0.6 to 1.2) and no trend according to cumulative duration (p for trend=0.68). CONCLUSION: We found no clear evidence concerning an association between night shift work and stomach cancer risk