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Background and Objective: The ischemia-reperfusion (IR) injury is a main feature of pathophysiological process in peripheral artery disease (PAD). In PAD, an exaggerated blood pressure response increases cardiovascular and cerebrovascular risks for the disease. Considering that L-type voltage-gated calcium channel (Cav1.2) in arterial vascular smooth muscle cells (VSMCs) plays a crucial role in regulating blood pressure, the purpose of this study was to determine the activities of Cav1.2 following hindlimb IR as well as a contribution of endothelin-1 (ET-1), a potent vasoconstrictor, to the activities of Cav1.2. Hypothesis: We hypothesized that IR injury of PAD upregulates ET-1 signaling pathways in limb muscle and thereby amplifies the activities of Cav1.2 in VSMCs. Methods: An experimental PAD model with IR was induced by 6 hours of ischemia followed by 18 hours of reperfusion in rats (IR18h rats). ELISA and western blot analysis were used to examine the levels of ET-1 in the hindlimb muscle, and protein expression of Cav1.2 and ET-1 receptor ETA in VSM. Patch clamp was used to determine the Cav1.2 currents. Data are presented as mean ± standard deviation. Results: The hindlimb IR increased the levels of ET-1 in the hindlimb muscle, and expression of Cav1.2 and ET-1’s ETA in VSMCs. In particular, compared with the control group, there was a promising trend for the increasing Cav1.2 in VSM of the IR18h group (1.00±0.61 in control/n=4 vs. 8.77±8.04 in IR18h/n=5, P=0.09). Meanwhile, ETA expression was significantly higher in IR18h group than control group (1.00±1.12 in control/n=4 vs. 3.71±1.59 in IR18h/n=5, P NIH R01 HL141198 & HL164571; and American Heart Association grant # 940567 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

This paper proposes a saturated smooth adaptive controller for regulating a certain type of underactuated Euler–Lagrange systems (UELSs) with modeling uncertainties and control saturations based on a singular perturbation approach. Compared with relevent literature, the advantages of the proposed controller include: (1) it renders the UELS semiglobally asymptotically track the desired position without the violation of control input constraints; (2) high-order derivatives of positions are not required in its implementation. The Hoppensteadt’s Theorem is employed to show that the proposed saturated controller renders the UELS semiglobally asymptotically stable about the desired set point with the satisfaction of control input constraints. The control effectiveness is validated by simulations on a two-link compliant robot arm.

Noble metals loading was found to be a promising strategy to improve the photocatalytic performance of g-C3N4. In this, we synthesized Ag/g-C3N4 composite (Ag/CN-sr) by an improved chemical reduction via ultrasonic spray technology. This process avoided the agglomeration of g-C3N4 nanosheets and created a micron-scale reaction condition, which promoted the uniform distribution and size reduction of Ag nanoclusters. The results indicated that the apparent reaction rate constant for RhB degradation was 0.0322 min−1, which was about 3 and 7 times higher than that of Ag/CN composite prepared by the conventional chemical reduction method (Ag/CN-cr) and bare g-C3N4 nanosheets, respectively. Furthermore, the degradation pathway of RhB was proposed by LC-MS and Multiwfn wave function analysis. For the first time, the frontier molecular orbital (FMO) analysis, orbital-weighted dual descriptor (OW DD) analysis and Atoms-In-Molecules (AIM) topological analysis were combined to study the degradation path of RhB from the atomic point of view. The theoretical analysis results were in good agreement with the LC-MS results.

A palladium-catalyzed asymmetric hydrogenation of levulinic acid has been successful developed by using Zn(OTf) 2 as co-catalyst. The present method not only has provided a strategy in the palladium-catalyzed asymmetric hydrogenation of ketone, but also allowed the preparation of a wide range of chiral I³-valerolactones in good yields with excellent enantioselectivities.

Colorectal cancer (CRC) is associated with high mortality worldwide and new targets are needed to overcome treatment resistance. Recent evidences highlight a role of the mitochondria calcium homeostasis in the development of CRC. In this context, we aimed to evaluate the role of the mitochondrial sodium-calcium-lithium exchanger (NCLX) and its targeting in CRC. We also identified curcumin as a new potential inhibitor of NCLX.In vitro, curcumin exerted strong anti-tumoral activity through its action on NCLX with mtCa2+ and reactive oxygen species overload associated with a mitochondrial membrane depolarization, leading to reduced ATP production and apoptosis through mitochondrial permeability transition pore opening concomitant with G2/M cell cycle arrest. NCLX inhibition with either CGP37157 (a benzodiazepine derivative), small interfering RNA-mediated knock-down or knockout approaches reproduced the effects of curcumin. Altered mitochondrial respiration, cellular aerobic glycolysis and endoplasmic reticulum–mitochondria membrane perturbations participated in these mechanisms. In a xenograft mouse model, NCLX inhibitors decreased CRC tumor growth. Both transcriptomic analysis of The Cancer Genome Atlas dataset and immunohistochemical analysis of tissue microarrays from 381 patients with microsatellite instability (MSI)-driven CRC demonstrated that higher NCLX expression was associated with MSI status and for the first time NCLX expression was significantly associated with recurrence-free survival in MSI CRC patients.Our findings provide strong evidence that blocking NCLX inhibits CRC in vitro and in vivo. We highlight a novel anti-tumoral mechanism of curcumin through its action on NCLX and mitochondria calcium overload that could benefit for therapeutic treatment of patients with MSI CRC.

The essential role of store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ (CRAC) channels in T cells is well established. In contrast, the contribution of individual Orai isoforms to SOCE and their downstream signaling functions in B cells are poorly understood. Here, we demonstrate changes in expression of Orai isoforms in response to B cell activation. We show that Orai3 and Orai1 are essential components of native CRAC channels in B cells and are critical for primary B cell proliferation and survival. The combined loss of Orai1 and Orai3 strongly impairs SOCE, nuclear factor for activated T cells (NFAT) activation, mitochondrial respiration, glycolysis, and the metabolic reprogramming of B cells in response to antigenic stimulation. Our results clarify the molecular composition and cellular functions of SOCE in B lymphocytes.

The novel nanocomposite Cu2O/MoS2-12 was synthesized by a simple two-step method. Cu2O nanospheres grow on the surface of MoS2 nanoflowers and have high photocatalytic activity. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM) X-ray photoelectron spectroscopy (XPS), ultraviolet-visible light (UV-vis) photoluminescence (PL) spectroscopy, UV-vis diffuse reflection (UV-DRS), and electrochemical impedance (EIS) were used to study the structure and properties of the samples. The photocatalytic properties of the materials were evaluated by degrading methyl orange (MO) under visible light. The results show that CM-12 can completely degrade MO in 30 min, and the pseudo-first-order kinetic constant of degradation is 8.76 times that of pure Cu2O, which can be attributed to the composite material that can greatly reduce the recombination rate of photogenerated electrons and holes, and it has good stability. After repeated use for 5 times, the degradation rate can still reach 40%. Through experiments and theoretical results, a possible photocatalytic mechanism is proposed. To the best of our knowledge, this work was the first example of combining MoS2 with Cu2O and applying it to photocatalytic degradation of organic pollutants. It was beneficial for developing new photocatalysts and improving the catalytic performance of conventional photocatalysts.

Cellular senescence has evolved as a protective mechanism to arrest growth of cells with oncogenic potential but is accompanied by the often pathologically deleterious senescence-associated secretory phenotype (SASP). Here we demonstrate an H2O2-dependent functional disruption controlling senescence-associated Ca2+ homeostasis and the SASP. Senescent cells fail to respond to H2O2-dependent plasma lamellar Ca2+ entry when compared to pre-senescent cells. Limiting exposure to senescence-associated H2O2 restores H2O2-dependent Ca2+ entry as well as transient receptor potential cation channel subfamily C member 6 (TRPC6) function. SA-TRPC6 and SASP expression is blocked by restoring Ca2+ entry with the TRP channel antagonist SKF-96365 or by the mTOR inhibitors rapamycin and Ku0063794. Together, our findings provide compelling evidence that redox and mTOR-mediated regulation of Ca2+ entry through TRPC6 modulates SASP gene expression and approaches which preserve normal Ca2+ homeostasis may prove useful in disrupting SASP activity. Impact statement Through its ability to evoke responses from cells in a paracrine fashion, the senescence-associated secretory phenotype (SASP) has been linked to numerous age-associated disease pathologies including tumor invasion, cardiovascular dysfunction, neuroinflammation, osteoarthritis, and renal disease. Strategies which limit the amplitude and duration of SASP serve to delay age-related degenerative decline. Here we demonstrate that the SASP regulation is linked to shifts in intracellular Ca2+ homeostasis and strategies which rescue redox-dependent calcium entry including enzymatic H2O2 scavenging, TRP modulation, or mTOR inhibition block SASP and TRPC6 gene expression. As Ca2+ is indispensable for secretion from both secretory and non-secretory cells, it is exciting to speculate that the expression of plasma lamellar TRP channels critical for the maintenance of intracellular Ca2+ homeostasis may be coordinately regulated with the SASP.

Voltage-gated L-type Ca2+ channel (Cav1.2) blockers (LCCBs) are major drugs for treating hypertension, the preeminent risk factor for heart failure. Vascular smooth muscle cell (VSMC) remodeling is a pathological hallmark of chronic hypertension. VSMC remodeling is characterized by molecular rewiring of the cellular Ca2+ signaling machinery, including down-regulation of Cav1.2 channels and up-regulation of the endoplasmic reticulum (ER) stromal-interacting molecule (STIM) Ca2+ sensor proteins and the plasma membrane ORAI Ca2+ channels. STIM/ORAI proteins mediate store-operated Ca2+ entry (SOCE) and drive fibro-proliferative gene programs during cardiovascular remodeling. SOCE is activated by agonists that induce depletion of ER Ca2+, causing STIM to activate ORAI. Here, we show that the three major classes of LCCBs activate STIM/ORAI-mediated Ca2+ entry in VSMCs. LCCBs act on the STIM N terminus to cause STIM relocalization to junctions and subsequent ORAI activation in a Cav1.2-independent and store depletion-independent manner. LCCB-induced promotion of VSMC remodeling requires STIM1, which is up-regulated in VSMCs from hypertensive rats. Epidemiology showed that LCCBs are more associated with heart failure than other antihypertensive drugs in patients. Our findings unravel a mechanism of LCCBs action on Ca2+ signaling and demonstrate that LCCBs promote vascular remodeling through STIM-mediated activation of ORAI. Our data indicate caution against the use of LCCBs in elderly patients or patients with advanced hypertension and/or onset of cardiovascular remodeling, where levels of STIM and ORAI are elevated.

The essential role of ORAI1 channels in receptor-evoked Ca2+ signaling is well understood, yet little is known about the physiological activation of the ORAI channel trio natively expressed in all cells. The roles of ORAI2 and ORAI3 have remained obscure. We show that ORAI2 and ORAI3 channels play a critical role in mediating the regenerative Ca2+ oscillations induced by physiological receptor activation, yet ORAI1 is dispensable in generation of oscillations. We reveal that ORAI2 and ORAI3 channels multimerize with ORAI1 to expand the range of sensitivity of receptor-activated Ca2+ signals, reflecting their enhanced basal STIM1-binding and heightened Ca2+-dependent inactivation. This broadened bandwidth of Ca2+ influx is translated by cells into differential activation of NFAT1 and NFAT4 isoforms. Our results uncover a long-sought role for ORAI2 and ORAI3, revealing an intricate control mechanism whereby heteromerization of ORAI channels mediates graded Ca2+ signals that extend the agonist-sensitivity to fine-tune transcriptional control.

This study used constitutive CD226 gene knockout (KO) mice as a model to investigate the functions and mechanisms of CD226 in megakaryocyte (MK) maturation and platelet activation. Although CD226 deficiency did not cause MK polyploidization or platelet granule abnormalities, increased MK counts were detected in the femora bone marrow (BM) and spleen of CD226 KO mice. Particularly, CD226 KO mice have a more extensive membrane system in MKs and platelets than wild-type (WT) mice. We also demonstrated that CD226 KO mice displayed increased platelet counts, shortened bleeding time, and enhanced platelet aggregation. CD226 KO platelets had an increased mature platelet ratio compared to the control platelets. In addition, the observed reduction in bleeding time may be due to decreased nitric oxide (NO) production in the platelets. Platelet-specific CD226-deficient mice showed similar increased MK counts, shortened bleeding time, enhanced platelet aggregation, and decreased NO production in platelets. Furthermore, we performed middle cerebral artery occlusion-reperfusion surgery on WT and CD226 KO mice to explore the potential effect of CD226 on acute ischemia-reperfusion injury; the results revealed that CD226 deficiency led to significantly increased infarct area. Thus, CD226 is a promising candidate for the treatment of thrombotic disorders.

Store-operated calcium (Ca2+) entry is an important homeostatic mechanism in cells, whereby the release of Ca2+ from intracellular endoplasmic reticulum stores triggers the activation of a Ca2+ influx pathway. Mediated by Orai1, this Ca2+ influx has specific and essential roles in biological processes as diverse as lactation to immunity. Although pharmacological inhibitors of this Ca2+ influx mechanism have helped to define the role of store-operated Ca2+ entry in many cellular events, the lack of isoform specific modulators and activators of Orai1 has limited our full understanding of these processes. Here we report the identification and synthesis of an Orai1 activity enhancer that concurrently potentiated Orai1 Ca2+-dependent inactivation (CDI). This unique enhancer of Orai1 had only a modest effect on Orai3 with weak inhibitory effects at high concentrations in intact MCF-7 breast cancer cells. The Orai1 enhancer heightened vascular smooth muscle cell migration induced by platelet-derived growth factor and the unique store-operated Ca2+ entry pathway present in skeletal muscle cells. These studies show that IA65 is an exemplar for the translation and development of Orai isoform selective agents. The ability of IA65 to activate CDI demonstrates that agents can be developed that can enhance Orai1-mediated Ca2+ influx but avoid the cytotoxicity associated with sustained Orai1 activation. IA65 and/or future analogues with similar Orai1- and CDI-activating properties could function to fine-tune physiological processes important in specific disease states, such as cellular migration and immune cell function.

The first ring-opening addition of a benzylic C(sp3)-H bond to azabenzonorbornadienes is demonstrated. The reaction proceeded under the catalytic system of [Cp*CoI2(CO)], AgSbF6 and Fe(OAc)2 in PhOMe. The methodology showed a good substrate scope with up to 96% yield. The relative configuration of the product was determined as cis-configuration by X-ray crystallography.

Concern about rising rates of obesity has prompted searches for its genetic risk determinants in genome-wide association studies (GWAS). Most genetic variants that contribute to the increased risk of a given trait are probably regulatory single nucleotide polymorphisms (SNPs). However, identifying plausible regulatory SNPs is difficult because of their varied locations relative to their target gene and linkage disequilibrium, which makes most GWAS-derived SNPs only proxies for many fewer functional SNPs. We developed a systematic approach to prioritizing GWAS-derived obesity SNPs using detailed epigenomic and transcriptomic analysis in adipose tissue vs. heterologous tissues. From 50 obesity-related GWAS and 121,064 expanded SNPs, we prioritized 47 potential causal regulatory SNPs (Tier-1 SNPs) for 14 gene loci. A detailed examination of seven of these genes revealed that four (CABLES1, PC, PEMT, and FAM13A) had Tier-1 SNPs that might regulate alternative use of transcription start sites resulting in different polypeptides being generated or different amounts of an intronic microRNA gene being expressed. HOXA11 and long noncoding RNA gene RP11-392O17.1 had Tier-1 SNPs in their 3’ or promoter region, respectively, and strong preferences for expression in subcutaneous vs. visceral adipose tissue. ZBED3-AS1 had two intragenic Tier-1 SNPs, each of which might contribute to mediating obesity risk through modulating long-distance chromatin interactions. We conclude that prioritization of regulatory SNP candidates should focus on their surrounding epigenetic features in a trait-relevant tissue. Our approach not only revealed especially credible novel regulatory SNPs, but also helped evaluate previously highlighted obesity GWAS SNPs that were candidates for transcription regulation.

Significance Stromal-interacting molecule 1 (STIM1) proteins are essential for the function of store-operated Ca2+ entry (SOCE). Using transcriptomics, metabolomics, imaging, and inducible smooth muscle–specific STIM1 knockout mice expressing genetically encoded Ca2+ sensors, we reveal a crucial function of STIM1 in airway remodeling and airway hyperresponsiveness in asthma. STIM1-mediated Ca2+ oscillations in airway smooth muscle (ASM) cells are critical for ASM remodeling through metabolic and transcriptional reprogramming and cytokine secretion, including IL-6. These effects are driven by Ca2+-dependent activation of the transcription factor isoform NFAT4 specifically in ASM. Our data provide evidence that ASM STIM1 and SOCE are central triggers of asthma manifestations and advocate for the future use of STIM1 as a molecular target in asthma therapy., Airway remodeling and airway hyperresponsiveness are central drivers of asthma severity. Airway remodeling is a structural change involving the dedifferentiation of airway smooth muscle (ASM) cells from a quiescent to a proliferative and secretory phenotype. Here, we show up-regulation of the endoplasmic reticulum Ca2+ sensor stromal-interacting molecule 1 (STIM1) in ASM of asthmatic mice. STIM1 is required for metabolic and transcriptional reprogramming that supports airway remodeling, including ASM proliferation, migration, secretion of cytokines and extracellular matrix, enhanced mitochondrial mass, and increased oxidative phosphorylation and glycolytic flux. Mechanistically, STIM1-mediated Ca2+ influx is critical for the activation of nuclear factor of activated T cells 4 and subsequent interleukin-6 secretion and transcription of pro-remodeling transcription factors, growth factors, surface receptors, and asthma-associated proteins. STIM1 drives airway hyperresponsiveness in asthmatic mice through enhanced frequency and amplitude of ASM cytosolic Ca2+ oscillations. Our data advocates for ASM STIM1 as a target for asthma therapy.

Protein kinase C (PKC)-ε is required for membrane addition during IgG-mediated phagocytosis, but its role in this process is ill defined. Here, we performed high-resolution imaging, which reveals that PKC-ε exits the Golgi and enters phagosomes on vesicles that then fuse. TNF and PKC-ε colocalize at the Golgi and on vesicles that enter the phagosome. Loss of PKC-ε and TNF delivery upon nocodazole treatment confirmed vesicular transport on microtubules. That TNF+ vesicles were not delivered in macrophages from PKC-ε null mice, or upon dissociation of the Golgi-associated pool of PKC-ε, implies that Golgi-tethered PKC-ε is a driver of Golgi-to-phagosome trafficking. Finally, we established that the regulatory domain of PKC-ε is sufficient for delivery of TNF+ vesicles to the phagosome. These studies reveal a novel role for PKC-ε in focal exocytosis – its regulatory domain drives Golgi-derived vesicles to the phagosome, whereas catalytic activity is required for their fusion. This is one of the first examples of a PKC requirement for vesicular trafficking and describes a novel function for a PKC regulatory domain.This article has an associated First Person interview with the first author of the paper.

Mitochondrial Ca2+ uptake tailors the strength of stimulation of plasma membrane phospholipase C–coupled receptors to that of cellular bioenergetics. However, how Ca2+ uptake by the mitochondrial Ca2+ uniporter (MCU) shapes receptor-evoked interorganellar Ca2+ signaling is unknown. Here, we used CRISPR/Cas9 gene knockout, subcellular Ca2+ imaging, and mathematical modeling to show that MCU is a universal regulator of intracellular Ca2+ signaling across mammalian cell types. MCU activity sustains cytosolic Ca2+ signaling by preventing Ca2+-dependent inactivation of store-operated Ca2+ release–activated Ca2+ channels and by inhibiting Ca2+ extrusion. Paradoxically, MCU knockout (MCU-KO) enhanced cytosolic Ca2+ responses to store depletion. Physiological agonist stimulation in MCU-KO cells led to enhanced frequency of cytosolic Ca2+ oscillations, endoplasmic reticulum Ca2+ refilling, nuclear translocation of nuclear factor for activated T cells transcription factors, and cell proliferation, without altering inositol-1,4,5-trisphosphate receptor activity. Our data show that MCU has dual counterbalancing functions at the cytosol–mitochondria interface, whereby the cell-specific MCU-dependent cytosolic Ca2+ clearance and buffering capacity of mitochondria reciprocally regulate interorganellar Ca2+ transfer and nuclear factor for activated T cells nuclear translocation during receptor-evoked signaling. These findings highlight the critical dual function of the MCU not only in the acute Ca2+ buffering by mitochondria but also in shaping endoplasmic reticulum and cytosolic Ca2+ signals that regulate cellular transcription and function., SCOPUS: ar.j, info:eu-repo/semantics/published

Antigen receptor stimulation triggers cytosolic Ca

In this paper, two saturated nonlinear control strategies are proposed for regulation of SEA-driven robots based on singular perturbation (SP) and Energy Shaping (ES). The SP-based saturated controller is designed with two saturated control terms for cascaded two subsystems, and the ES-based saturated controller is proposed by a saturated PD control term plus a static gravity compensator. In comparison of the two controllers, the SP-based saturated controller requires the stiffness being relative large, while the ES-based saturated controller requires accurate stiffness knowledge. Satisfaction of the control saturation is guaranteed by using the hyperbolic tangent function in controllers design. Asymptotical control stability is analyzed using the Hoppensteadts Theorem and the Krasovskii-LaSalle theorem, and the control effectiveness is illustrated by simulations and experiments.

Rejection is a common complication of allogeneic tissue transplantation. Fixation of splenocytes (SP) with 1‐ethyl‐3‐(3'‐dimethylaminopropyl)‐carbodiimide (ECDI) induces immune tolerance in recipients post‐transplantation; however, the mechanism underlying this effect remains unclear. Here, we determined the mechanisms of ECDI‐fixed donor SP (ECDI‐SP) in inducing tolerance in skin allograft transplantation. C57BL/6‐recipient mice that received Balb/c full‐thickness skin transplants with two infusions of donor‐derived ECDI‐SP, along with rapamycin showed superior skin allograft survival and lower inflammatory cell infiltration than mice that received rapamycin‐only treatment. In ECDI‐SP‐treated mice, the levels of anti‐inflammatory cytokines such as interleukin (IL)‐10 in sera were markedly increased, whereas the expression of inflammatory cytokines was significantly suppressed. Splenic macrophages were significantly polarized to the alternative activated macrophage (M2) phenotype, with expansion of CD4+Foxp3+ regulatory T cells (Tregs) in the spleen and draining lymph nodes. Allostimulatory activity of ECDI‐SP in vitro and donor‐specific ex vivo hyporesponsiveness were observed. C57BL/6 macrophages engulfed allogeneic Balb/c‐derived ECDI‐SP, polarized to the M2 phenotype, with pronounced cAMP response element‐binding (CREB) protein phosphorylation. By facilitating increased IL‐10 expression, ECDI‐SP induced M2 polarization and Treg production, inhibiting effector T‐cell proliferation. Thus, ECDI‐SP modulates macrophage M2 polarization by increasing CREB phosphorylation and promoting Treg production to suppress allogeneic skin graft rejection.