Spontaneous calcium activity in metanephric mesenchymal cells regulates branching morphogenesis in the embryonic kidney.

The central role of calcium signaling during development of early vertebrates is well documented, but little is known about its role in mammalian embryogenesis. We have used immunofluorescence and time-lapse calcium imaging of cultured explanted embryonic rat kidneys to study the role of calcium signaling for branching morphogenesis. In mesenchymal cells, we recorded spontaneous calcium activity that was characterized by irregular calcium transients. The calcium signals were dependent on release of calcium from intracellular stores in the endoplasmic reticulum. Down-regulation of the calcium activity, both by blocking the sarco-endoplasmic reticulum Ca2+-ATPase and by chelating cytosolic calcium, resulted in retardation of branching morphogenesis and a reduced formation of primitive nephrons but had no effect on cell proliferation. We propose that spontaneous calcium activity contributes with a stochastic factor to the self-organizing process that controls branching morphogenesis, a major determinant of the ultimate number of nephrons in the kidney.-Fontana, J. M., Khodus, G. R., Unnersjö-Jess, D., Blom, H., Aperia, A., Brismar, H. Spontaneous calcium activity in metanephric mesenchymal cells regulates branching morphogenesis in the embryonic kidney.

Impact of noise exposure on the circadian clock in the auditory system.

Circadian rhythms control the timing of all bodily functions, and misalignment in the rhythms can cause various diseases. Moreover, circadian rhythms are highly conserved and are regulated by a transcriptional-translational feedback loop of circadian genes that has a periodicity of approximately 24 h. The cochlea and the inferior colliculus (IC) have been shown to possess an autonomous and self-sustained circadian system as demonstrated by recording, in real time, the bioluminescence from PERIOD2::LUCIFERASE (PER2::LUC) mice. The cochlea and IC both express the core clock genes, Per1, Per2, Bmal1, and Rev-Erbα, where RNA abundance is rhythmically distributed with a 24 h cycle. Noise exposure alters clock gene expression in the cochlea and the IC after noise stimulation, although in different ways. These findings highlight the importance of circadian responses in the cochlea and the IC and emphasize the importance of circadian mechanisms for understanding the differences in central and peripheral auditory function and the subsequent molecular changes that occur after daytime (inactive phase) or nighttime (active phase) noise trauma.

WHOLE-BODY CRYOSTIMULATION: A REHABILITATION BOOSTER.

A growing body of work suggests that whole-body cryostimulation (WBC) could play a role as a promising adjuvant therapy in various conditions of rehabilitation interest. In fact, WBC is currently being used to relieve symptoms in rheumatoid arthritis, fibromyalgia, ankylosing spondylitis, depression and anxiety, multiple sclerosis, sleep disturbances, muscle soreness after strenuous physical exercise, post-Covid syndrome and obesity. WBC is not only a symptomatic physical therapy but rather represents an "adaptation therapy" because of the repeated shock-like cryogenic cold stimulus over the entire body surface that induces reactions in the autonomic, endocrine, circulatory, neuromuscular and immunological systems, resulting in an adaptation that contributes to the restoration of the homeostatic state. Therefore, based on the existing evidence, WBC can be described as follows:a "training method" for the autonomic nervous system;a novel anti-inflammatory and antioxidant treatment;a treatment with beneficial effects on body composition and adipose tissue. In our opinion, the powerful effects of thermal stress on the physiological responses of the human body present unique features that could potentially be exploited to boost rehabilitation outcomes in various conditions. Therefore, we believe it is important to highlight the potential use of WBC for medical use and emphasize its relevance in the field of rehabilitation with the aim of stimulating scientific studies on the efficacy of WBC as an adjuvant treatment in various conditions of rehabilitation interest.

Differential effects of noise exposure between substrains of CBA mice.

Noise trauma involves a plethora of mechanisms including reactive oxygen species, apoptosis, tissue damage, and inflammation. Recently, circadian mechanisms were also found to contribute to the vulnerability to noise trauma in mice, with greater damage occurring during their active phase (nighttime), when compared to similar noise exposures during their inactive phase (daytime). These effects seem to be regulated by mechanisms involving Bdnf responses to noise trauma and circulating levels of corticosterone (CORT). However, recent studies using different noise paradigms show contradicting results and it remains unclear how universal these findings are. Here we show that these findings differ even between substrains of mice and are restricted to a narrow window of noise intensity. We found that CBA/Sca mice exposed to 103 dB SPL display differential day/night noise sensitivity as measured by auditory brainstem responses (ABRs), but not at 100 (where full recovery is observed in day or night exposed mice) or 105 dB SPL (where permanent damage is found in both groups). In contrast, neither CBA/CaJ or CBA/JRj displayed such differences in day/night noise sensitivity, whatever noise intensity used. These effects appeared to be independent from outer hair cell function, as distortion product otoacoustic emissions appeared equally affected by day or night noise exposure, in all strains and in all noise conditions. Minor differences in ribbon counts or synaptic pairing were found in CBA/Sca mice, which were inconsistent with ABR wave 1 amplitude changes. Interestingly, CORT levels peaked in CBA/Sca mice at the onset of darkness at zeitgeber time 12 reaching levels of 43.8 ng/ml, while in the CBA/CaJ and the CBA/JRj, levels were 11.9 and 15.6 ng/ml respectively and peaking 4 h earlier (zeitgeber time 8). These findings were consistent with higher period of daily rhythm in CBA/Sca mice when measured in complete darkness using running wheels (23.7 h), than in CBA/CaJ (23.45 h) or CBA/JRj (23.13 h). In conclusion, our study suggests that the differential vulnerability to noise trauma between inactive and active phase is not universal and is as sensitive as substrain differences that might be governed by the circadian amplitude of the circulating CORT profiles.

Solute transporters and aquaporins are impaired in celiac disease.

BACKGROUND INFORMATION: Celiac disease is a chronic inflammatory disorder of the small bowel induced in genetically susceptible subjects by gluten ingestion. Diarrhoea, weight loss and malabsorption represent the major clinical presentation of the disease. Here we examined the possible alteration in the expression and localization of water channels [AQPs (aquaporins)] and some solute transporters in duodenal mucosa of celiac disease patients. Duodenal biopsies from untreated celiacs, treated celiacs, healthy controls and disease controls were considered in the present study. The expressions of some AQPs and transporter mRNAs in human duodenal biopsies were determined by semi-quantitative RT-PCR (reverse transcription PCR) and real-time RT-PCR. The localization of AQPs 3, 7 and 10 and of SGLT1 (Na+/glucose co-transporter 1), PEPT1 (H+/oligopeptide transporter 1) and NHE3 (Na+/H+ exchanger 3) was evaluated by immunohistochemistry. RESULTS: AQPs 3, 7, 10 and 11, SGLT, PEPT and NHE, CFTR (cystic fibrosis transmembrane conductance regulator) and NKCC (Na-K-2Cl co-transporter) mRNAs were expressed in duodenal biopsies of healthy controls, treated celiac patients and disease controls. The expression of transcripts was virtually absent in duodenal biopsies of untreated celiac disease patients except for CFTR and NKCC. In healthy controls, immunohistochemistry revealed a labelling in the apical membrane of surface epithelial cells of the duodenum. The immunolabelling was heavily reduced or absent in untreated celiac patients, while it was normal in patients consuming a gluten-free diet for at least 12 months. CONCLUSIONS: Our results indicate that the main routes for water and solute absorption are deficient in celiac disease and may play a role in the onset of malabsorption symptoms.

Super-resolution microscopy reveals that Na+/K+-ATPase signaling protects against glucose-induced apoptosis by deactivating Bad.

Activation of the apoptotic pathway is a major cause of progressive loss of function in chronic diseases such as neurodegenerative and diabetic kidney diseases. There is an unmet need for an anti-apoptotic drug that acts in the early stage of the apoptotic process. The multifunctional protein Na+,K+-ATPase has, in addition to its role as a transporter, a signaling function that is activated by its ligand, the cardiotonic steroid ouabain. Several lines of evidence suggest that sub-saturating concentrations of ouabain protect against apoptosis of renal epithelial cells, a common complication and major cause of death in diabetic patients. Here, we induced apoptosis in primary rat renal epithelial cells by exposing them to an elevated glucose concentration (20 mM) and visualized the early steps in the apoptotic process using super-resolution microscopy. Treatment with 10 nM ouabain interfered with the onset of the apoptotic process by inhibiting the activation of the BH3-only protein Bad and its translocation to mitochondria. This occurred before the pro-apoptotic protein Bax had been recruited to mitochondria. Two ouabain regulated and Akt activating Ca2+/calmodulin-dependent kinases were found to play an essential role in the ouabain anti-apoptotic effect. Our results set the stage for further exploration of ouabain as an anti-apoptotic drug in diabetic kidney disease as well as in other chronic diseases associated with excessive apoptosis.

The -374T/A RAGE polymorphism protects against future cardiac events in nondiabetic patients with coronary artery disease.

BACKGROUND: The -374T/A polymorphism of the Receptor for Advanced Glycation End products (RAGE) may exert a protective effect toward the development of atherosclerosis. No data are currently available on the potential prognostic role of this polymorphism in patients with angiographically proven coronary artery disease (CAD). Hereto we sought to address this issue in a large consecutive cohort of patients undergoing coronary revascularization. METHODS: A total of 643 CAD patients who underwent myocardial revascularization were followed for 4.2 years (interquartile range: 2.2-8.1 years). The rates of major cardiac adverse events (death, nonfatal myocardial infarction, and unstable angina) were compared according to the -374T/A RAGE polymorphism. RESULTS: During a median follow-up period of 4.2 years, the study endpoint was reached by 126/643 patients (19.6%). We observed adverse cardiac events in 13.4% of patients with AA, 17.5% of those with AT, and 24.2% of those with TT genotype (p <0.05). In univariate Cox proportional hazard analysis, the AA genotype was significantly related to a better outcome in nondiabetic patients (hazard ratio: 0.47, 95% CI: 0.20-0.96; p <0.05). No association was found with adverse events in diabetic subjects. After allowance for potential confounders, the AA genotype remained a significant prognostic factor in the nondiabetic group (adjusted HR: 0.41, 95% CI: 0.17-0.94, p <0.05). CONCLUSIONS: The -374T/A RAGE polymorphism is an independent protective factor for cardiac events in nondiabetic patients with CAD. The effect of this genetic variant seems to be attenuated in diabetics, who have chronic RAGE upregulation.

Transport and release of colloidal 3-mercaptopropionic acid-coated CdSe-CdS/ZnS core-multishell quantum dots in human umbilical vein endothelial cells.

Colloidal semiconductor quantum dots (QDs) have been extensively researched and developed for biomedical applications, including drug delivery and biosensing assays. Hence, it is pivotal to understand their behavior in terms of intracellular transport and toxicological effects. In this study, we focused on 3-mercaptopropionic acid-coated CdSe-CdS/ZnS core-multishell quantum dots (3MPA-QDs) converted from the as-grown octadecylamine-coated quantum dots (ODA-QDs) and their direct and dynamic interactions with human umbilical vein endothelial cells (HUVECs). Live cell imaging using confocal fluorescence microscopy showed that 3MPA-QDs first attached to and subsequently aggregated on HUVEC plasma membrane ~25 min after QD deposition. The aggregated QDs started being internalized at ~2 h and reached their highest internalization degree at ~24 h. They were released from HUVECs after ~48 h. During the 48 h period, the HUVECs responded normally to external stimulations, grew, proliferated and wound healed without any perceptible apoptosis. Furthermore, 1) 3MPA-QDs were internalized in newly formed LysoTracker-stained early endosomes; 2) adenosine 5'-triphosphate-induced [Ca2+]i modulation caused a transient decrease in the fluorescence of 3MPA-QDs that were attached to the plasma membrane but a transient increase in the internalized 3MPA-QDs; and 3) fluorescence signal modulations of co-stained LysoTracker and QDs induced by the lysosomotropic agent Gly-Phe-ß-naphthylamide were spatially co-localized and temporally synchronized. Our findings suggest that 3MPA-QDs converted from ODA-QDs are a potential nontoxic fluorescent probe for future use in clinical applications. Moreover, the photophysical strategy and techniques reported in this work are easily applicable to study of direct interactions between other nanoparticles and live cells; contributing to awareness and implementation of the safe applications of nanoparticles.

Quantum dots modulate intracellular Ca2+ level in lung epithelial cells.

While adverse effects of nanoparticles on lung health have previously been proposed, few studies have addressed the direct effects of nanoparticle exposure on the airway epithelium. In this work, we examine the response of the pulmonary airway to nanoparticles by measuring intracellular Ca2+ concentration ([Ca2+]i) in the Calu-3 epithelial layer stimulated by 3-mercaptopropionic-acid (3MPA) coated CdSe-CdS/ZnS core-multishell quantum dots (QDs). Simultaneous transient transepithelial electrical resistance (TEER) decrease and global [Ca2+]i increase in Calu-3 epithelial layer, accompanied by cell displacements, contraction, and expansion, were observed under QD deposition. This suggests that a QD-induced global [Ca2+]i increase in the Calu-3 epithelial layer caused the transient TEER decrease. The [Ca2+]i increase was marked and rapid in the apical region, while [Ca2+]i decreased in the basolateral region of the epithelial layer. TEER transient response and extracellular Ca2+ entry induced by QD deposition were completely inhibited in cells treated with stretched-activated (SA) inhibitor GdCl3 and store-operated calcium entry (SOCE) inhibitor BTP2 and in cells immersed in Ca2+-free medium. The voltage-gated calcium channel (VGCC) inhibitor nifedipine decreased, stabilized, and suppressed the TEER response, but did not affect the [Ca2+]i increase, due to QD deposition. This demonstrates that the Ca2+ influx activated by QDs' mechanical stretch occurs through activation of both SA and SOCE channels. QD-induced [Ca2+]i increase occurred in the Calu-3 epithelial layer after culturing for 15 days, while significant TEER drop only occurred after 23 days. This work provides a new perspective from which to study direct interactions between airway epithelium and nanoparticles and may help to reveal the pathologies of pulmonary disease.

Calcium oscillations triggered by cardiotonic steroids.

Na(+), K(+)-ATPase (NKA) is well known for its function as an ion pump. Studies during the last decade have revealed an additional role for NKA as a signal transducer. In this brief review, we describe how cardiotonic steroids, which are highly specific NKA ligands, trigger slow Ca(2+) oscillations by promoting the interaction between NKA and the inositol trisphosphate receptor, and how this Ca(2+) signal activates the NF-κB subunit p65 and increases the expression of the antiapoptotic factor Bcl-xL. The potential tissue-protective effects of this signal are discussed.

Preliminary evidence of a genetic association between chromosome 9p21.3 and human longevity.

BACKGROUND: Emerging evidence suggests that there is a significant genetic component to human longevity. One or more genetic variants located on chromosome 9p21.3 and tagged by the single-nucleotide polymorphism (SNP) rs1333049 (G/C) are major risk factors for age-related disorders, including acute myocardial infarction (AMI), stroke, and dementia. We hypothesized that this locus may have widespread effects on aging phenotypes and, as such, influences the ability to achieve a long and healthy life. AIM: The aim of this study was to assess whether the rs1333049 polymorphism is associated with human longevity. METHODS: We tested the rs1333049 polymorphism in a sample of 80 healthy centenarians (39 men and 41 women, aged 100-104), 218 patients younger than 40 who experienced an AMI, and a control group of 258 healthy young volunteers matched to AMI patients for age and sex. RESULTS: The frequency of the C allele of rs1333049 was significantly lower in centenarians compared to young controls, whereas AMI patients showed a higher frequency. After adjustment for gender and traditional vascular risk factors, the C allele of rs1333049 remained significantly associated with a reduced likelihood to reach longevity: Odds ratio (OR) 0.64, 95% confidence interval (CI) 0.39-0.89, p < 0.01. CONCLUSIONS: Our data suggest that the rs1333049 polymorphism at 9p21.3 may influence successful human longevity, possibly by modulating the risk of age-related disorders.