Photoelectrochemical Ni-catalyzed cross-coupling of aryl bromides with amine at ultra-low potential.

Photoelectrochemical (PEC) cell is an ideal platform for organic transformation because of its green benefits and minimal energy consumption. As an emerging methodology, the reaction types of photoelectrocatalytic organic synthesis (PECOS) are limited to simple oxidation and C-H activation at current stage. Metal catalysis for the construction of C(sp2)-N bonds has not been touched yet in PECOS. We introduce here a PEC method that successfully engages Ni catalysis for the mild production of aniline derivatives. Experimental and computational investigations elucidate that the addition of photoanode-generated amine radical to Ni catalyst avoids the sluggish nucleophilic attack, enabling the reaction to proceed at an ultra-low potential (-0.4 V vs. Ag/AgNO3) and preventing the overoxidation of products in conventional electrochemical synthesis. This synergistic catalysis strategy exhibits good functional group tolerance and wide substrate scope on both aryl halides and amines, by which some important natural products and pharmaceutical chemicals have been successfully modified.

Customized Photoelectrochemical C-N and C-P Formation Enabled by Tailored Deposition on Photoanodes.

Photoelectrochemistry (PEC) is burgeoning as an innovative solution to organic synthesis. However, the current PEC system suffers limited reaction types and unsatisfactory performances. Herein, we employ efficient BiVO4 photoanode with tailored deposition layers for customizing two PEC approaches toward C-N and C-P formation. Notably, our process proceeds under mild reaction conditions, easily available substrates, and ultra-low potentials. Beyond photocatalysis and electrocatalysis, customized PEC offers high efficiency, good functional group tolerance, and substantial applicability for decorating drug molecules, highlighting its promising potential to enrich the synthetic toolbox for broader organic chemistry of practical applications.

Addition of α-synuclein aggregates to the intestinal environment recapitulates Parkinsonian symptoms in model systems.

The gut-brain axis plays a vital role in Parkinson's disease (PD). The mechanisms of gut-brain transmission mainly focus on α-synuclein deposition, intestinal inflammation and microbiota function. A few studies have shown the trigger of PD pathology in the gut. α-Synuclein is highly conserved in food products, which was able to form ß-folded aggregates and to infect the intestinal mucosa. In this study we investigated whether α-synuclein-preformed fibril (PFF) exposure could modulate the intestinal environment and induce rodent models replicating PD pathology. We first showed that PFF could be internalized into co-cultured Caco-2/HT29/Raji b cells in vitro. Furthermore, we demonstrated that PFF perfusion caused the intestinal inflammation and activation of enteric glial cells in an ex vivo intestinal organ culture and in an in vivo intestinal mouse coloclysis model. Moreover, we found that PFF exposure through regular coloclysis induced PD pathology in wild-type (WT) and A53T α-synuclein transgenic mice with various phenotypes. Particularly in A53T mice, PFF induced significant behavioral disorders, intestinal inflammation, α-synuclein deposition, microbiota dysbiosis, glial activation as well as degeneration of dopaminergic neurons in the substantia nigra. In WT mice, however, the PFF induced only mild behavioral abnormalities, intestinal inflammation, α-synuclein deposition, and glial activation, without significant changes in microbiota and dopaminergic neurons. Our results reveal the possibility of α-synuclein aggregates binding to the intestinal mucosa and modeling PD in mice. This study may shed light on the investigation and early intervention of the gut-origin hypothesis in neurodegenerative diseases.

Exercise Reduces Airway Smooth Muscle Contraction in Asthmatic Rats via Inhibition of IL-4 Secretion and Store-Operated Ca2+ Entry Pathway.

PURPOSE: Increased evidence has shown that aerobic exercise reduces airway hyperresponsiveness in asthmatic individuals. However, the underlying mechanisms of action remain elusive. This study aimed to investigate the effect of exercise on airway smooth muscle (ASM) contractile function in asthmatic rats, and uncover the possible involvement of interleukin 4 (IL-4) and the store-operated Ca2+ entry (SOCE) pathway. METHODS: In this study, chicken ovalbumin was used to induce asthma in male Sprague-Dawley rats. The exercise group received moderate-intensity aerobic exercise training for 4 weeks. IL-4 concentrations in bronchoalveolar lavage fluid (BALF) samples were evaluated by enzyme linked immunosorbent assay. The contractile function of the ASM was investigated using tracheal ring tension experiments and intracellular Ca2+ imaging techniques. Western blot analysis was used to evaluate expression levels of calcium-release activated calcium (CRAC) channel protein (Orai) and stromal interaction molecule 1 (STIM1) in ASM. RESULTS: Our data showed that the carbachol-stimulated, SOCE-mediated contraction of rat ASM was significantly increased in asthmatic rats, which could be abolished by exercise. Pharmacological studies revealed that GSK5498A and BTP-2, selective blockers of CRAC channels significantly inhibited SOCE-induced ASM contraction. In addition, exercise inhibited the up-regulation of IL-4 in BALF as well as STIM1 and Orai expression in the ASM of asthmatic rats. In line with these observations, we demonstrated that pretreatment of the ASM with IL-4 up-regulated the expression level of STIM1, Orai1 and Orai2, thereby promoting SOCE-mediated ASM contraction. CONCLUSIONS: The data in this study reveal that aerobic exercise may improve the ASM contractile function in asthmatic rats by inhibiting IL-4 secretion and by down-regulating the expression of STIM1, Orai1 and Orai2, thus decreasing excessive SOCE-mediated ASM contraction in asthmatic rats.

Role of Orai3-Mediated Store-Operated Calcium Entry in Radiation-Induced Brain Microvascular Endothelial Cell Injury.

Radiation-induced brain injury is a serious complication with complex pathogenesis that may accompany radiotherapy of head and neck tumors. Although studies have shown that calcium (Ca2+) signaling may be involved in the occurrence and development of radiation-induced brain injury, the underlying molecular mechanisms are not well understood. In this study, we used real-time quantitative polymerase chain reaction and Western blotting assays to verify our previous finding using next-generation sequencing that the mRNA and protein expression levels of Orai3 in rat brain microvascular endothelial cells (rBMECs) increased after X-ray irradiation. We next explored the role of Orai3 and Orai3-mediated store-operated Ca2+ entry (SOCE) in radiation-induced brain injury. Primary cultured rBMECs derived from wild-type and Orai3 knockout (Orai3(-/-)) Sprague-Dawley rats were used for in vitro experiments. Orai3-mediated SOCE was significantly increased in rBMECs after X-ray irradiation. However, X-ray irradiation-induced SOCE increase was markedly reduced in Orai3 knockout rBMECs, and the percentage of BTP2 (a nonselective inhibitor of Orai channels)-inhibited SOCE was significantly decreased in Orai3 knockout rBMECs. Functional studies indicated that X-ray irradiation decreased rBMEC proliferation, migration, and tube formation (a model for assessing angiogenesis) but increased rBMEC apoptosis, all of which were ameliorated by BTP2. In addition, occurrences of all four functional deficits were suppressed in X-ray irradiation-exposed rBMECs derived from Orai3(-/-) rats. Cerebrovascular damage caused by whole-brain X-ray irradiation was much less in Orai3(-/-) rats than in wild-type rats. These findings provide evidence that Orai3-mediated SOCE plays an important role in radiation-induced rBMEC damage and brain injury and suggest that Orai3 may warrant development as a potential therapeutic target for reducing or preventing radiation-induced brain injury.

X-Ray Causes mRNA Transcripts Change to Enhance Orai2-Mediated Ca2+ Influx in Rat Brain Microvascular Endothelial Cells.

Background: Radiation-induced brain injury is a serious and treatment-limiting complication of brain radiation therapy. Although endothelial cell dysfunction plays a critical role in the development of this pathogenesis, the underlying molecular mechanisms remain elusive. Methods: Primary cultured rat brain microvascular endothelial cells (BMECs) were divided into five groups without or with exposure of x-rays delivered at 5 Gy or 20 Gy. For the irradiated groups, cells were continued to cultivate for 12 or 24 h after being irradiated. Then the mRNA libraries of each group were established and applied for next-generation sequencing. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were conducted to analyze the sequencing results. Quantitative polymerase chain reaction, western blotting, cck8 assay and intracellular calcium concentration assays were conducted to analyze the role of Orai2-associated SOCE in x-ray induced cellular injury. Results: In total, 3,005 transcripts in all the four x-ray-exposed groups of BMECs showed expression level changes compared with controls. With the dose of x-ray augment and the following cultured time extension, the numbers of differentially expressed genes (DEGs) increased significantly in BMECs. Venn diagrams identified 40 DEGs common to all four exposure groups. Functional pathway enrichment analyses indicated that those 40 DEGs were enriched in the calcium signaling pathway. Among those 40 DEGs, mRNA and protein expression levels of Orai2 were significantly upregulated for 24 h. Similarly, calcium influx via store-operated calcium entry, which is modulated by Orai2, was also significantly increased for 24 h in x-ray-exposed BMECs. Moreover, the change in SOCE was suppressed by btp-2, which is a non-selective inhibitor of Orai. Additionally, x-ray exposure induced a significant decrease of proliferation in BMECs in the dose- and time-dependent manner. Conclusion: These findings provide evidence for molecular mechanisms underlying BMECs dysfunction in development of radiation-induced brain injury and suggest new approaches for therapeutic targets.

IL-17 stimulates neutrophils to release S100A8/A9 to promote lung epithelial cell apoptosis in Mycoplasma pneumoniae-induced pneumonia in children.

Mycoplasma pneumoniae-induced pneumonia (MPP) is a common cause of community-acquired respiratory tract infections, increasing risk of morbidity and mortality, in children. However, diagnosing early-stage MPP is difficult owing to the lack of good diagnostic methods. Here, we examined the protein profile of bronchoalveolar lavage fluid (BALF) and found that S100A8/A9 was highly expressed. Enzyme-linked immunosorbent assays used to assess protein levels in serum samples indicated that S100A8/A9 concentrations were also increased in serum obtained from children with MPP, with no change in S100A8/A9 levels in children with viral or bacterial pneumonia. In vitro, S100A8/A9 treatment significantly increased apoptosis in a human alveolar basal epithelial cell line (A549 cells). Bioinformatics analyses indicated that up-regulated S100A8/A9 proteins participated in the interleukin (IL)-17 signaling pathway. The origin of the increased S100A8/A9 was investigated in A549 cells and in neutrophils obtained from children with MPP. Treatment of neutrophils, but not of A549 cells, with IL-17A released S100A8/A9 into the culture medium. In summary, we demonstrated that S100A8/A9, possibly released from neutrophils, is a new potential biomarker for the clinical diagnosis of children MPP and involved in the development of this disease through enhancing apoptosis of alveolar basal epithelial cells.

Effect of oxLDL on transcriptional expression of human lens epithelial cells.

Age-related cataract patients regularly have hypertension, hyperglycemia, and hyperlipidemia. In oxidative conditions, increased reactive oxygen species can oxidize natural low-density lipoprotein into oxidative low-density lipoprotein (oxLDL). However, the relationship between oxLDL and the occurrence of cataracts is still unclear. In this study, 1515 differentially expressed transcripts were identified by analyzing the results of RNA sequencing in a human lens epithelial cell line (HLEpiC). Compared with control groups, oxLDL-treated HLEpiC had 806 up-regulated transcripts and 709 down-regulated transcripts. Our genome-wide transcriptome results showed that differentially expressed genes, such as Rho signaling (Rho A and Cdc42) and Na+/K+-ATPase family (ATP1B1), are involved in lens epithelial cell differentiation and cell homeostasis. In conclusion, oxLDL greatly influences transcriptional expression and these differentially expressed genes may play an important role in the development of cataracts. Our findings may provide new targets in the treatment for cataracts.

TRPV4 Complexes With the Na+/Ca2+ Exchanger and IP3 Receptor 1 to Regulate Local Intracellular Calcium and Tracheal Tension in Mice.

Intracellular Ca2+ is critical for regulating airway smooth muscle (ASM) tension. A rapid rise in the intracellular Ca2+ concentration ([Ca2+]i) of ASM cells is crucial for modulating the intensity and length of the ASM contraction. Because this rapid increase in [Ca2+]i largely depends on the balance between Ca2+ released from intracellular Ca2+ stores and extracellular Ca2+ entry, exploring the mechanisms mediating Ca2+ transport is critical for understanding ASM contractility and the pathogenesis of bronchial contraction disorders. Transient receptor potential vanilloid 4 (TRPV4) is a highly Ca2+-permeable non-selective cation channel that mediates Ca2+ influx to increase [Ca2+]i, which then directly or indirectly regulates the contraction and relaxation of ASM. The [Ca2+]i returns to basal levels through several uptake and extrusion pumps, such as the sarco(endo)plasmic reticulum Ca2+ ATPase and inositol 1,4,5-trisphosphate receptors (IP3Rs), the plasmalemmal Ca2+ ATPase, and the plasma membrane Na+/Ca2+ exchanger (NCX). Thus, to further understand ASM tension regulation in normal and diseased tissue, the present study examined whether an interaction exists among TRPV4, IP3Rs, and NCX. The TRPV4-specific and potent agonist GSK1016790A increased [Ca2+]i in mouse ASM cells, an effect that was completely blocked by the TRPV4-specific antagonist HC067047. However, GSK1016790A induced relaxation in mouse tracheal rings precontracted with carbachol in vitro. To determine the mechanism underlying this TRPV4-induced relaxation of ASM, we blocked specific downstream molecules. We found that the GSK1016790A-induced relaxation was abolished by the NCX inhibitors KB-R7943 and LiCl but not by specific inhibitors of the Ca2+-activated large-, intermediate-, or small-conductance K+ channels (BKCa, IK, and SK3, respectively). The results of co-immunoprecipitation (co-IP) assays showed an interaction of TRPV4 and IP3R1 with NCXs. Taken together, these findings support a physical and functional interaction of TRPV4 and IP3R1 with NCXs as a novel TRPV4-mediated Ca2+ signaling mechanism and suggest a potential target for regulation of ASM tension and treatment of respiratory diseases, especially tracheal spasm.

Ratiometric Piezochromism of Electrospun Polymer Films: Intermolecular Interactions for Enhanced Sensitivity and Color Difference.

Many piezochromic luminescent (PCL) dyes are known for their fluorescent switching capacity in the powdered phase, but they are usually difficult to utilize practically owing to poor mechanical properties. Herein, a nanofiber film fabricated through an electrospinning process is doped with PCL dye. The electrospun film not only reveals the mechanics of macromolecular materials, but also achieves precise, gradient pressure recognition (ratiometric PCL behavior). The PCL sensitivity and color difference of the dye in a crystalline state are calculated to be 15.7 nm GPa-1 and 149 nm, respectively. The sensitivity of an electrospun film containing 0.1 % (w/w) dye decreased to 3.6 nm GPa-1 . Moreover, the individual effects of molecular conformation and intermolecular interaction on the PCL properties have been clearly distinguished through in situ high-pressure experiments. Intermolecular interactions play a more significant role in PCL color difference and sensitivity. The film fabricated through an electrospinning process contributes to understanding of the working mechanism and real applications of piezochromic materials.