Histone variant H2A.Z is required for plant salt response by regulating gene transcription.

As a well-conserved histone variant, H2A.Z epigenetically regulates plant growth and development as well as the interaction with environmental factors. However, the role of H2A.Z in response to salt stress remains unclear, and whether nucleosomal H2A.Z occupancy work on the gene responsiveness upon salinity is obscure. Here, we elucidate the involvement of H2A.Z in salt response by analysing H2A.Z disorder plants with impaired or overloaded H2A.Z deposition. The salt tolerance is dramatically accompanied by H2A.Z deficiency and reacquired in H2A.Z OE lines. H2A.Z disorder changes the expression profiles of large-scale of salt responsive genes, announcing that H2A.Z is required for plant salt response. Genome-wide H2A.Z mapping shows that H2A.Z level is induced by salt condition across promoter, transcriptional start site (TSS) and transcription ending sites (-1 kb to +1 kb), the peaks preferentially enrich at promoter regions near TSS. We further show that H2A.Z deposition within TSS provides a direct role on transcriptional control, which has both repressive and activating effects, while it is found generally H2A.Z enrichment negatively correlate with gene expression level response to salt stress. This study shed light on the H2A.Z function in salt tolerance, highlighting the complex regulatory mechanisms of H2A.Z on transcriptional activity for yielding appropriate responses to particularly environmental stress.

The importance of preoperative T3 stage substaging by 3D endorectal ultrasonography for the prognosis of middle and low rectal cancer.

OBJECTIVE: The study aimed to validate the role of 3D-endorectal ultrasonography in prognosis and recurrence for patients with T3-stage rectal cancer by evaluating the preoperative extramural depth of tumor invasion. METHODS: In this study, we investigated the medical records of rectal cancer patients who were admitted to Changhai Hospital's Colorectal Surgery Division. The sample group was categorized into three subgroups (T3a, T3b, and T3c) based on the extent of tumor progression (<5 mm, 5-10 mm, and >10 mm) to assess the endorectal ultrasonography diagnostic performance. The 5-year disease-free survival and overall survival were assessed using the Kaplan-Meier method and a log rank test. Cox regression analysis verified the tumor invasion depth's significance as a prognostic predictor, and it was also utilized to evaluate other independent risk variables for recurrence after surgery. RESULTS: The study included 72 individuals with low and middle rectal cancer from January 2014 to November 2019. Twenty-two individuals had stage T3a, 22 had stage T3b, and 28 had stage T3c based on preoperative endorectal ultrasonography. Endorectal ultrasonography had 88.0%, 86.8%, and 76.2% overall accuracy for stratifying subgroups, respectively. According to the Kaplan-Meier curve, 5-year OS was 100%, 83.5%, and 92.9% for T3a, T3b, and T3c (p = 0.172), and 5-year disease-free survival was 100%, 80.8%, and 72.9% for T3a, T3b, and T3c, respectively (p = 0.014). A distinct risk factor for 5-year disease-free survival was the degree of tumor infiltration (p = 0.039). CONCLUSION: Preoperative T3 stage subdivision allows for categorization of prognosis and survival. Endorectal ultrasonography reports should make explicit declarations of T3a, T3b, and T3c scales.

RP11-296E3.2 acts as an important molecular chaperone for YBX1 and promotes colorectal cancer proliferation and metastasis by activating STAT3.

BACKGROUND: RP11-296E3.2 is a novel long noncoding RNA (lncRNA) associated with colorectal cancer (CRC) metastasis, that was reported in our previous clinical studies. However, the mechanisms of RP11-296E3.2 in colorectal tumorigenesis remain elusive. METHODS: RNA sequencing (RNA-seq), Fluorescence in situ hybridization (FISH), Transwell assays and others, were performed to evaluate the function of RP11-296E3.2 for proliferation and metastasis in vitro. In situ and metastatic tumor models were performed to evaluate the function of RP11-296E3.2 for proliferation and metastasis in vivo. RNA-pulldown, RNA-interacting protein immunoprecipitation (RIP), tissue microarray (TMA) assay, a luciferase reporter assay, chromatin immunoprecipitation (ChIP) and others were performed to explore the mechanisms by which RP11-296E3.2 regulates CRC tumorigenesis. RESULTS: RP11-296E3.2 was confirmed to be associated with CRC cell proliferation and metastasis in vitro and in vivo. Mechanistically, RP11-296E3.2 directly bound to recombinant Y-Box Binding Protein 1 (YBX1) and enhanced signal transducer and activator of transcription 3 (STAT3) transcription and phosphorylation. YBX1 promoted the CRC cell proliferation and migration, while knockdown of RP11-296E3.2 attenuated the effects of YBX1 on CRC cell proliferation, and metastasis and the expression of several related downstream genes. We are the first to discover and confirm the existence of the YBX1/STAT3 pathway, a pathway dependent on RP11-296E3.2. CONCLUSION: Together, these novel findings show that the RP11-296E3.2/YBX1 pathway promotes colorectal tumorigenesis and progression by activating STAT3 transcription and phosphorylation, and suggest that RP11-296E3.2 is a potential diagnostic biomarker and therapeutic target in CRC.

Two New Species of Talaromyces Sect. Trachyspermi Discovered in China.

Two new species of sect. Trachyspermi isolated from soil are proposed, namely, T. albidus (ex-type AS3.26143T) and T. rubidus (ex-type AS3.26142T), based on the integrated taxonomic methods. Morphologically, T. albidus is characterized by slow growth, white gymnothecia, singly-borne asci and ellipsoidal echinulate ascospores. Talaromyces rubidus is distinguished by restricted growth, moderate to abundant red soluble pigment on CYA and YES, biverticillate penicilli, and  commonly ovoid to globose echinulate conidia. The two proposed novelties are further confirmed by the phylogenetic analyses of the concatenated BenA-CaM-Rpb2-ITS sequence matrix and the individual BenA, CaM, Rpb2 and ITS sequence matrices. Talaromyces albidus is closely related to T. assiutensis and T. trachyspermus, while T. rubidus is in the clade containing T. albobiverticillius, T. rubrifaciens, T. catalonicus, T. heiheensis, T. erythromellis, T. halophytorum, T. pernambucoensis, T. solicola and T. aerius.

[Treadmill exercise alleviates neuropathic pain by regulating mitophagy of the anterior cingulate cortex in rats].

This study aimed to investigate the effect of treadmill exercise on neuropathic pain and to determine whether mitophagy of the anterior cingulate cortex (ACC) contributes to exercise-mediated amelioration of neuropathic pain. Chronic constriction injury of the sciatic nerve (CCI) was used to establish a neuropathic pain model in Sprague-Dawley (SD) rats. Von-Frey filaments were used to assess the mechanical paw withdrawal threshold (PWT), and a thermal radiation meter was used to assess the thermal paw withdrawal latency (PWL) in rats. qPCR was used to evaluate the mRNA levels of Pink1, Parkin, Fundc1, and Bnip3. Western blot was used to evaluate the protein levels of PINK1 and PARKIN. To determine the impact of the mitophagy inducer carbonyl cyanide m-chlorophenylhydrazone (CCCP) on pain behaviors in CCI rats, 24 SD rats were randomly divided into CCI drug control group (CCI+Veh group), CCI+CCCP low-dose group (CCI+CCCP0.25), CCI+CCCP medium-dose group (CCI+CCCP2.5), and CCI+CCCP high-dose group (CCI+CCCP5). Pain behaviors were assessed on 0, 1, 3, 5, and 7 days after modeling. To explore whether exercise regulates pain through mitophagy, 24 SD rats were divided into sham, CCI, and CCI+Exercise (CCI+Exe) groups. The rats in the CCI+Exe group underwent 4-week low-moderate treadmill training one week after modeling. The mechanical pain and thermal pain behaviors of the rats in each group were assessed on 0, 7, 14, 21, and 35 days after modeling. Western blot was used to detect the levels of the mitophagy-related proteins PINK1, PARKIN, LC3 II/LC3 I, and P62 in ACC tissues. Transmission electron microscopy was used to observe the ultrastructure of mitochondrial morphology in the ACC. The results showed that: (1) Compared with the sham group, the pain thresholds of the ipsilateral side of the CCI group decreased significantly (P < 0.001). Meanwhile, the mRNA and protein levels of Pink1 were significantly higher, and those of Parkin were lower in the CCI group (P < 0.05). (2) Compared with the CCI+Veh group, each CCCP-dose group showed higher mechanical and thermal pain thresholds, and the levels of PINK1 and LC3 II/LC3 I were elevated significantly (P < 0.05, P < 0.01). (3) The pain thresholds of the CCI+Exe group increased significantly compared with those of the CCI group after treadmill intervention (P < 0.001, P < 0.01). Compared with the CCI group, the protein levels of PINK1 and P62 were decreased (P < 0.001, P < 0.01), and the protein levels of PARKIN and LC3 II/LC3 I were increased in the CCI+Exe group (P < 0.01, P < 0.05). Rod-shaped mitochondria were observed in the ACC of CCI+Exe group, and there were little mitochondrial fragmentation, swelling, or vacuoles. The results suggest that the mitochondrial PINK1/PARKIN autophagy pathway is blocked in the ACC of neuropathic pain model rats. Treadmill exercise could restore mitochondrial homeostasis and relieve neuropathic pain via the PINK1/PARKIN pathway.

HDAC4 promotes the growth and metastasis of gastric cancer via autophagic degradation of MEKK3.

BACKGROUND: Histone deacetylases (HDACs) have been shown to be involved in tumorigenesis, but their precise role and molecular mechanisms in gastric cancer (GC) have not yet been fully elucidated. METHODS: Bioinformatics screening analysis, qRT-PCR, and immunohistochemistry (IHC) were used to identify the expression of HDAC4 in GC. In vitro and in vivo functional assays illustrated the biological function of HDAC4. RNA-seq, GSEA pathway analysis, and western blot revealed that HDAC4 activated p38 MAPK signalling. Immunofluorescence, western blot, and IHC verified the effect of HDAC4 on autophagy. ChIP and dual-luciferase reporter assays demonstrated that the transcriptional regulation mechanism of HDAC4 and ATG4B. RESULTS: HDAC4 is upregulated in GC and correlates with poor prognosis. In vitro and in vivo assays showed that HDAC4 contributes to the malignant phenotype of GC cells. HDAC4 inhibited the MEF2A-driven transcription of ATG4B and prevented MEKK3 from p62-dependent autophagic degradation, thus activating p38 MAPK signalling. Reciprocally, the downstream transcription factor USF1 enhanced HDAC4 expression by regulating HDAC4 promoter activity, forming a positive feedback loop and continuously stimulating HDAC4 expression and p38 MAPK signalling activation. CONCLUSION: HDAC4 plays an oncogenic role in GC, and HDAC4-based targeted therapy would represent a novel strategy for GC treatment.

Amelioration of circadian disruption and calcium-handling protein defects by choline alleviates cardiac remodeling in abdominal aorta coarctation rats.

The key pathophysiological process leading to heart failure is cardiac remodeling, a term referring to cardiac hypertrophy, fibrosis, and apoptosis. We explored circadian rhythm disruption and calcium dyshomeostasis in cardiac remodeling and investigated the cardioprotective effect of choline. The experiments were conducted using a model of cardiac remodeling by abdominal aorta coarctation (AAC) in Sprague-Dawley rats. In vitro cardiomyocyte remodeling was induced by exposing neonatal rat cardiomyocytes to angiotensin II. The circadian rhythms of the transcript levels of the seven major components of the mammalian clock (Bmal1, Clock, Rev-erbα, Per1/2, and Cry1/2) were altered in AAC rat hearts during a normal 24 h light/dark cycle. AAC also upregulated the levels of proteins that mediate store-operated Ca2+ entry/receptor-operated Ca2+ entry (stromal interaction molecule 1 [STIM1], Orai1, and transient receptor potential canonical 6 [TRPC6]) in rat hearts. Moreover, choline ameliorated circadian rhythm disruption, reduced the upregulated protein levels of STIM1, Orai1, and TRPC6, and alleviated cardiac dysfunction and remodeling (evidenced by attenuated cardiac hypertrophy, fibrosis, and apoptosis) in AAC rats. In vitro analyses showed that choline ameliorated calcium overload, downregulated STIM1, Orai1, and TRPC6, and inhibited thapsigargin-induced store-operated Ca2+ entry and 1-oleoyl-2-acetyl-sn-glycerol-induced receptor-operated Ca2+ entry in angiotensin II-treated cardiomyocytes. In conclusion, choline attenuated AAC-induced cardiac remodeling and cardiac dysfunction, which was related to amelioration of circadian rhythm disruption and attenuation of calcium-handling protein defects. Modulation of vagal activity by choline targeting the circadian rhythm and calcium homeostasis may have therapeutic potential for cardiac remodeling and heart failure.

A phase 1 study of LY3076226, a fibroblast growth factor receptor 3 (FGFR3) antibody-drug conjugate, in patients with advanced or metastatic cancer.

Background We report a Phase 1 study of LY3076226, an antibody-drug conjugate composed of human IgG1 monoclonal antibody against the human FGFR3 attached with a cleavable linker to the maytansine derivative DM4 in patients with advanced or metastatic cancer. Methods This study was comprised of two parts: (A) dose escalation in patients with advanced or metastatic cancer and (B) dose expansion in patients with urothelial carcinoma with locally determined FGFR3 alterations. The dose range of LY3076226 tested was 0.2-5.0 mg/kg as an intravenous infusion on Day 1 of each 21-day cycle. The primary objective was to determine a recommended phase 2 dose (RP2D). Results Twenty-five patients were enrolled (Part A: 22, Part B: 3) and received ≥ 1 dose of LY3076226. No dose-limiting toxicities were reported. LY3076226 was generally well tolerated; most of the toxicities were Grade 1 or 2. Two patients experienced treatment-related Grade 3 toxicity (embolism and decreased platelet count). Four patients experienced serious adverse events (not treatment-related), all in Part A. Dose-proportional exposure was observed, with an estimated half-life of 2-7 days. No responses were seen with LY3076226 treatment. Stable disease persisting for > 6 months was observed in 1 patient receiving 3.2 mg/kg of LY3076226. Conclusion The study demonstrates acceptable safety and tolerability of LY3076226 up to the 5.0 mg/kg dose. Recruitment was stopped due to pipeline prioritization. Dose escalation of LY3076226 beyond 5.0 mg/kg in patients with advanced tumors may be possible. The trial was registered on August 19, 2015 under identifier NCT02529553 with ClinicalTrials.gov.

Activation of M3AChR (Type 3 Muscarinic Acetylcholine Receptor) and Nrf2 (Nuclear Factor Erythroid 2-Related Factor 2) Signaling by Choline Alleviates Vascular Smooth Muscle Cell Phenotypic Switching and Vascular Remodeling.

OBJECTIVE: Phenotypic switching of vascular smooth muscle cells (VSMCs) plays a critical role in atherosclerosis, vascular restenosis, and hypertension. Choline exerts cardioprotective effects; however, little is known about its effects on VSMC phenotypic switching and vascular remodeling. Here, we investigated whether choline modulates VSMC phenotypic changes and explored the underlying mechanisms. Approach and Results: In cultured VSMCs, choline promoted Nrf2 (nuclear factor erythroid 2-related factor 2) nuclear translocation, inducing the expression of HO-1 (heme oxygenase-1) and NQO-1 (NAD[P]H quinone oxidoreductase-1). Consequently, choline ameliorated Ang II (angiotensin II)-induced increases in NOX (NAD[P]H oxidase) expression and the mitochondrial reactive oxygen species level, thereby attenuating Ang II-induced VSMC phenotypic switching, proliferation, and migration, presumably via M3AChRs (type 3 muscarinic acetylcholine receptors). Downregulation of M3AChR or Nrf2 diminished choline-mediated upregulation of Nrf2, HO-1, and NQO-1 expression, as well as inhibition of VSMC phenotypic transformation, suggesting that M3AChR and Nrf2 activation are responsible for the protective effects of choline. Moreover, activation of the Nrf2 pathway by sulforaphane suppressed Ang II-induced VSMC phenotypic switching and proliferation, indicating that Nrf2 is a key regulator of VSMC phenotypic switching and vascular homeostasis. In a rat model of abdominal aortic constriction in vivo, choline attenuated VSMC phenotypic transformation and vascular remodeling in a manner related to activation of the Nrf2 pathway. CONCLUSIONS: These results reveal that choline impedes VSMC phenotypic switching, proliferation, migration, and vascular remodeling by activating M3AChR and Nrf2-antioxidant signaling and suggest a novel role for Nrf2 in VSMC phenotypic modulation.

Expression of fatty acid-binding protein-4 in gastrointestinal stromal tumors and its significance for prognosis.

BACKGROUND: Fatty acid-binding proteins (FABPs) have been found to be involved in tumorigenesis and development. However, the role of FABP4, a member of the FABPs, in GISTs (Gastrointestinal stromal tumors) remains unclear. This study aimed to investigate the expression of FABP4 and its prognostic value in GISTs. METHODS: FABP4 expression in 125 patients with GISTs was evaluated by immunohistochemical analysis of tissue microarrays. The relationship between FABP4 expression and clinicopathological features and prognosis of GISTs was analyzed. RESULTS: Multiple logistic regression analysis showed that expression of FABP4 correlated with tumor size and mitotic index. Furthermore, FABP4 level, tumor size, mitotic index, and high AFIP-Miettinen risk were independent prognostic factors in GISTs. The Kaplan-Meier survival curve showed that the 5-year survival rate of patients with high-FABP4 expression GISTs was lower. CONCLUSIONS: These results suggested that high-FABP4 expression might be a marker of malignant phenotype of GISTs and poor prognosis.

Pyridostigmine regulates glucose metabolism and mitochondrial homeostasis to reduce myocardial vulnerability to injury in diabetic mice.

Diabetic patients are more susceptible to myocardial ischemia damage than nondiabetic patients, with worse clinical outcomes and greater mortality. The mechanism may be related to glucose metabolism, mitochondrial homeostasis, and oxidative stress. Pyridostigmine may improve vagal activity to protect cardiac function in cardiovascular diseases. Researchers have not determined whether pyridostigmine regulates glucose metabolism and mitochondrial homeostasis to reduce myocardial vulnerability to injury in diabetic mice. In the present study, autonomic imbalance, myocardial damage, mitochondrial dysfunction, and oxidative stress were exacerbated in isoproterenol-stimulated diabetic mice, revealing the myocardial vulnerability of diabetic mice to injury compared with mice with diabetes or exposed to isoproterenol alone. Compared with normal mice, the expression of glucose transporters (GLUT)1/4 phosphofructokinase (PFK) FB3, and pyruvate kinase isoform (PKM) was decreased in diabetic mice, but increased in isoproterenol-stimulated normal mice. Following exposure to isoproterenol, the expression of (GLUT)1/4 phosphofructokinase (PFK) FB3, and PKM decreased in diabetic mice compared with normal mice. The downregulation of SIRT3/AMPK and IRS-1/Akt in isoproterenol-stimulated diabetic mice was exacerbated compared with that in diabetic mice or isoproterenol-stimulated normal mice. Pyridostigmine improved vagus activity, increased GLUT1/4, PFKFB3, and PKM expression, and ameliorated mitochondrial dysfunction and oxidative stress to reduce myocardial damage in isoproterenol-stimulated diabetic mice. Based on these results, it was found that pyridostigmine may reduce myocardial vulnerability to injury via the SIRT3/AMPK and IRS-1/Akt pathways in diabetic mice with isoproterenol-induced myocardial damage. This study may provide a potential therapeutic target for myocardial damage in diabetic patients.

Synthesis and Evaluation of Aminothiazole Derivatives as Hedgehog Pathway Inhibitors.

A series of aminothiazole derivatives bearing the benzimidazole moiety were synthesized and evaluated in Gli luciferase reporter assays. Lead optimization led to the discovery of potent hedgehog pathway antagonist 18 (2-[3-(1H-benzimidazol-2-yl)-4-chloroanilino]-N-[4-(trifluoromethyl)phenyl]-1,3-thiazole-4-carboxamide), with IC50 values in nanomolar range. The molecular basis ascribed to hindering sonic hedgehog-driven Smoothened (Smo) localization within the primary cilium (PC). Moreover, compound 18 inhibited Gli1 mRNA expression in mutant Smo cell line and displayed moderate cytotoxicity against DAOY cancer cell.

[Recent progress on obesity-induced myocardial remodeling and its possible mechanism of mitochondrial dyshomeostasis].

Obesity is an important risk factor for cardiovascular diseases, which can lead to a variety of cardiovascular diseases including myocardial remodeling. Obesity may induce myocardial dysfunction by affecting hemodynamics, inducing autonomic imbalance, adipose tissue dysfunction, and mitochondrial dyshomeostasis. The key necessary biochemical functions for metabolic homeostasis are performed in mitochondria, and mitochondrial homeostasis is considered as one of the key determinants for cell viability. Mitochondrial homeostasis is regulated by dynamic regulation of mitochondrial fission and fusion, as well as mitochondrial cristae remodeling, biogenesis, autophagy, and oxidative stress. The mitochondrial fission-fusion and morphological changes of mitochondrial cristae maintain the integrity of the mitochondrial structure. The mitochondria maintain a "healthy" state by balancing biogenesis and autophagy, while reactive oxygen species can act as signaling molecules to regulate intracellular signaling. The excessive accumulation of lipids and lipid metabolism disorder in obesity leads to mitochondrial dyshomeostasis, which activate the apoptotic cascade and lead to myocardial remodeling. In this review, we provide an overview of the recent research progress on obesity-induced myocardial remodeling and its possible mechanism of mitochondrial dyshomeostasis.

Hypoxia selectively upregulates cation channels and increases cytosolic [Ca2+] in pulmonary, but not coronary, arterial smooth muscle cells.

Ca2+ signaling, particularly the mechanism via store-operated Ca2+ entry (SOCE) and receptor-operated Ca2+ entry (ROCE), plays a critical role in the development of acute hypoxia-induced pulmonary vasoconstriction and chronic hypoxia-induced pulmonary hypertension. This study aimed to test the hypothesis that chronic hypoxia differentially regulates the expression of proteins that mediate SOCE and ROCE [stromal interacting molecule (STIM), Orai, and canonical transient receptor potential channel TRPC6] in pulmonary (PASMC) and coronary (CASMC) artery smooth muscle cells. The resting cytosolic [Ca2+] ([Ca2+]cyt) and the stored [Ca2+] in the sarcoplasmic reticulum were not different in CASMC and PASMC. Seahorse measurement showed a similar level of mitochondrial bioenergetics (basal respiration and ATP production) between CASMC and PASMC. Glycolysis was significantly higher in PASMC than in CASMC. The amplitudes of cyclopiazonic acid-induced SOCE and OAG-induced ROCE in CASMC are slightly, but significantly, greater than in PASMC. The frequency and the area under the curve of Ca2+ oscillations induced by ATP and histamine were also larger in CASMC than in PASMC. Na+/Ca2+ exchanger-mediated increases in [Ca2+]cyt did not differ significantly between CASMC and PASMC. The basal protein expression levels of STIM1/2, Orai1/2, and TRPC6 were higher in CASMC than in PASMC, but hypoxia (3% O2 for 72 h) significantly upregulated protein expression levels of STIM1/STIM2, Orai1/Orai2, and TRPC6 and increased the resting [Ca2+]cyt only in PASMC, but not in CASMC. The different response of essential components of store-operated and receptor-operated Ca2+ channels to hypoxia is a unique intrinsic property of PASMC, which is likely one of the important explanations why hypoxia causes pulmonary vasoconstriction and induces pulmonary vascular remodeling, but causes coronary vasodilation.

Pyridostigmine protects against cardiomyopathy associated with adipose tissue browning and improvement of vagal activity in high-fat diet rats.

Obesity, a major contributor to the development of cardiovascular diseases, is associated with an autonomic imbalance characterized by sympathetic hyperactivity and diminished vagal activity. Vagal activation plays important roles in weight loss and improvement of cardiac function. Pyridostigmine is a reversible acetylcholinesterase inhibitor, but whether it ameliorates cardiac lipid accumulation and cardiac remodeling in rats fed a high-fat diet has not been determined. This study investigated the effects of pyridostigmine on high-fat diet-induced cardiac dysfunction and explored the potential mechanisms. Rats were fed a normal or high-fat diet and treated with pyridostigmine. Vagal discharge was evaluated using the BL-420S system, and cardiac function by echocardiograms. Lipid deposition and cardiac remodeling were determined histologically. Lipid utility was assessed by qPCR. A high-fat diet led to a significant reduction in vagal discharge and lipid utility and a marked increase in lipid accumulation, cardiac remodeling, and cardiac dysfunction. Pyridostigmine improved vagal activity and lipid metabolism disorder and cardiac remodeling, accompanied by an improvement of cardiac function in high-fat diet-fed rats. An increase in the browning of white adipose tissue in pyridostigmine-treated rats was also observed and linked to the expression of UCP-1 and CIDEA. Additionally, pyridostigmine facilitated activation of brown adipose tissue via activation of the SIRT-1/AMPK/PGC-1α pathway. In conclusion, a high-fat diet resulted in cardiac lipid accumulation, cardiac remodeling, and a significant decrease in vagal discharge. Pyridostigmine ameliorated cardiomyopathy, an effect related to reduced cardiac lipid accumulation, and facilitated the browning of white adipose tissue while activating brown adipose tissue.

Acetylcholine attenuated TNF-α-induced intracellular Ca2+ overload by inhibiting the formation of the NCX1-TRPC3-IP3R1 complex in human umbilical vein endothelial cells.

The endoplasmic reticulum (ER) forms discrete junctions with the plasma membrane (PM) that play a critical role in the regulation of Ca2+ signaling during cellular bioenergetics, apoptosis and autophagy. We have previously confirmed that acetylcholine can inhibit ER stress and apoptosis after inflammatory injury. However, limited research has focused on the effects of acetylcholine on ER-PM junctions. In this work, we evaluated the structure and function of the supramolecular sodium-calcium exchanger 1 (NCX1)-transient receptor potential canonical 3 (TRPC3)-inositol 1,4,5-trisphosphate receptor 1 (IP3R1) complex, which is involved in regulating Ca2+ homeostasis during inflammatory injury. The width of the ER-PM junctions of human umbilical vein endothelial cells (HUVECs) was measured in nanometres using transmission electron microscopy and a fluorescent probe for Ca2+. Protein-protein interactions were assessed by immunoprecipitation. Ca2+ concentration was measured using a confocal microscope. An siRNA assay was employed to silence specific proteins. Our results demonstrated that the peripheral ER was translocated to PM junction sites when induced by tumour necrosis factor-alpha (TNF-α) and that NCX1-TRPC3-IP3R1 complexes formed at these sites. After down-regulating the protein expression of NCX1 or IP3R1, we found that the NCX1-mediated inflow of Ca2+ and the release of intracellular Ca2+ stores were reduced in TNF-α-treated cells. We also observed that acetylcholine attenuated the formation of NCX1-TRPC3-IP3R1 complexes and maintained calcium homeostasis in cells treated with TNF-α. Interestingly, the positive effects of acetylcholine were abolished by the selective M3AChR antagonist darifenacin and by AMPK siRNAs. These results indicate that acetylcholine protects endothelial cells from TNF-alpha-induced injury, [Ca2+]cyt overload and ER-PM interactions, which depend on the muscarinic 3 receptor/AMPK pathway, and that acetylcholine may be a new inhibitor for suppressing [Ca2+]cyt overload.

Vagal nerve stimulation improves mitochondrial dynamics via an M3 receptor/CaMKKß/AMPK pathway in isoproterenol-induced myocardial ischaemia.

Mitochondrial dynamics-fission and fusion-are associated with ischaemic heart disease (IHD). This study explored the protective effect of vagal nerve stimulation (VNS) against isoproterenol (ISO)-induced myocardial ischaemia in a rat model and tested whether VNS plays a role in preventing disorders of mitochondrial dynamics and function. Isoproterenol not only caused cardiac injury but also increased the expression of mitochondrial fission proteins [dynamin-related peptide1 (Drp1) and mitochondrial fission protein1 (Fis-1)) and decreased the expression of fusion proteins (optic atrophy-1 (OPA1) and mitofusins1/2 (Mfn1/2)], thereby disrupting mitochondrial dynamics and leading to increase in mitochondrial fragments. Interestingly, VNS restored mitochondrial dynamics through regulation of Drp1, Fis-1, OPA1 and Mfn1/2; enhanced ATP content and mitochondrial membrane potential; reduced mitochondrial permeability transition pore (MPTP) opening; and improved mitochondrial ultrastructure and size. Furthermore, VNS reduced the size of the myocardial infarction and ameliorated cardiomyocyte apoptosis and cardiac dysfunction induced by ISO. Moreover, VNS activated AMP-activated protein kinase (AMPK), which was accompanied by phosphorylation of Ca2+ /calmodulin-dependent protein kinase kinase ß (CaMKKß) during myocardial ischaemia. Treatment with subtype-3 of muscarinic acetylcholine receptor (M3 R) antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide or AMPK inhibitor Compound C abolished the protective effects of VNS on mitochondrial dynamics and function, suggesting that M3 R/CaMKKß/AMPK signalling are involved in mediating beneficial effects of VNS. This study demonstrates that VNS modulates mitochondrial dynamics and improves mitochondrial function, possibly through the M3 R/CaMKKß/AMPK pathway, to attenuate ISO-induced cardiac damage in rats. Targeting mitochondrial dynamics may provide a novel therapeutic strategy in IHD.

Long-term administration of pyridostigmine attenuates pressure overload-induced cardiac hypertrophy by inhibiting calcineurin signalling.

Cardiac hypertrophy is associated with autonomic imbalance, characterized by enhanced sympathetic activity and withdrawal of parasympathetic control. Increased parasympathetic function improves ventricular performance. However, whether pyridostigmine, a reversible acetylcholinesterase inhibitor, can offset cardiac hypertrophy induced by pressure overload remains unclear. Hence, this study aimed to determine whether pyridostigmine can ameliorate pressure overload-induced cardiac hypertrophy and identify the underlying mechanisms. Rats were subjected to either sham or constriction of abdominal aorta surgery and treated with or without pyridostigmine for 8 weeks. Vagal activity and cardiac function were determined using PowerLab. Cardiac hypertrophy was evaluated using various histological stains. Protein markers for cardiac hypertrophy were quantitated by Western blot and immunoprecipitation. Pressure overload resulted in a marked reduction in vagal discharge and a profound increase in cardiac hypertrophy index and cardiac dysfunction. Pyridostigmine increased the acetylcholine levels by inhibiting acetylcholinesterase in rats with pressure overload. Pyridostigmine significantly attenuated cardiac hypertrophy based on reduction in left ventricular weight/body weight, suppression of the levels of atrial natriuretic peptide, brain natriuretic peptide and ß-myosin heavy chain, and a reduction in cardiac fibrosis. These effects were accompanied by marked improvement of cardiac function. Additionally, pyridostigmine inhibited the CaN/NFAT3/GATA4 pathway and suppressed Orai1/STIM1 complex formation. In conclusion, pressure overload resulted in cardiac hypertrophy, cardiac dysfunction and a significant reduction in vagal discharge. Pyridostigmine attenuated cardiac hypertrophy and improved cardiac function, which was related to improved cholinergic transmission efficiency (decreased acetylcholinesterase and increased acetylcholine), inhibition of the CaN/NFAT3/GATA4 pathway and suppression of the interaction of Orai1/STIM1.

Specific α7 nicotinic acetylcholine receptor agonist ameliorates isoproterenol-induced cardiac remodelling in mice through TGF-ß1/Smad3 pathway.

It is well-accepted that inflammation plays an important role in the development of cardiac remodelling and that therapeutic approaches targeting inflammation can inhibit cardiac remodelling. Although a large amount of evidence indicates that activation of α7 nicotinic acetylcholine receptor (α7nAChR) causes an anti-inflammatory effect, the role of α7nAChR in cardiac remodelling and the underlying mechanism have not been established. To investigate the effect of the specific α7nAChR agonist, PNU282987, on cardiac remodelling induced by isoproterenol (ISO 60 mg/kg per day) in mice, the cardiomyocyte cross-sectional area (CSA) and collagen volume fraction were evaluated by hematoxylin and eosin (HE) and Masson staining, respectively. Cardiac function and ventricular wall thickness were measured by echocardiography. The protein expressions of collagen I, matrix metalloproteinase 9 (MMP-9), transforming growth factor ß1 (TGF-ß1), and Smad3 were analyzed by Western blot. ISO-induced cardiac hypertrophy, characterized by an increase in the heart weight/body weight ratio, CSA and ventricular wall thickness. Moreover, cardiac fibrosis indices, such as collagen volume fraction, MMP-9 and collagen I protein expression, were also increased by ISO. PNU282987 not only attenuated cardiac hypertrophy but also decreased the cardiac fibrosis induced by ISO. Furthermore, PNU282987 suppressed TGF-ß1 protein expression and the phosphorylation of Smad3 induced by ISO. In conclusion, PNU282987 ameliorated the cardiac remodelling induced by ISO, which may be related to the TGF-ß1/Smad3 pathway. These data imply that the α7nAChR may represent a novel therapeutic target for cardiac remodelling in many cardiovascular diseases.