Microbiota-derived acetate attenuates neuroinflammation in rostral ventrolateral medulla of spontaneously hypertensive rats.

BACKGROUND: Increased neuroinflammation in brain regions regulating sympathetic nerves is associated with hypertension. Emerging evidence from both human and animal studies suggests a link between hypertension and gut microbiota, as well as microbiota-derived metabolites short-chain fatty acids (SCFAs). However, the precise mechanisms underlying this gut-brain axis remain unclear. METHODS: The levels of microbiota-derived SCFAs in spontaneously hypertensive rats (SHRs) were determined by gas chromatography-mass spectrometry. To observe the effect of acetate on arterial blood pressure (ABP) in rats, sodium acetate was supplemented via drinking water for continuous 7 days. ABP was recorded by radio telemetry. The inflammatory factors, morphology of microglia and astrocytes in rostral ventrolateral medulla (RVLM) were detected. In addition, blood-brain barrier (BBB) permeability, composition and metabolomics of the gut microbiome, and intestinal pathological manifestations were also measured. RESULTS: The serum acetate levels in SHRs are lower than in normotensive control rats. Supplementation with acetate reduces ABP, inhibits sympathetic nerve activity in SHRs. Furthermore, acetate suppresses RVLM neuroinflammation in SHRs, increases microglia and astrocyte morphologic complexity, decreases BBB permeability, modulates intestinal flora, increases fecal flora metabolites, and inhibits intestinal fibrosis. CONCLUSIONS: Microbiota-derived acetate exerts antihypertensive effects by modulating microglia and astrocytes and inhibiting neuroinflammation and sympathetic output.

Probing Catalyst Function - Electronic Modulation of Chiral Polyborate Anionic Catalysts.

Boroxinate complexes of VAPOL and VANOL are a chiral anionic platform that can serve as a versatile staging arena for asymmetric catalysis. The structural underpinning of the platform is a chiral polyborate core that covalently links together alcohols (or phenols) and vaulted biaryl ligands. The polyborate platform is assembled in situ by the substrate of the reaction, and thus a multiplex of chiral catalysts can be rapidly assembled from various alcohols (or phenols) and bis-phenol ligands for screening of catalyst activity. In the present study, variations in the steric and electronic properties of the phenol/alcohol component of the boroxinate catalyst are probed to reveal their effects on the asymmetric induction in the catalytic asymmetric aziridination reaction. A Hammett study is consistent with a mechanism in which the two substrates are hydrogen-bonded to the boroxinate core in the enantiogenic step. The results of the Hammett study are supported by a computational study in which it is found that the H-O distance of the protonated imine hydrogen bonded to the anionic boroxinate core decreases with an increase in the electron releasing ability of the phenol unit incorporated into the boroxinate. The results are not consistent with a mechanism in which the boroxinate catalyst functions as a Lewis acid and activates the imine by a Lewis acid/Lewis base interaction.

CAF Proteins Help SOT1 Regulate the Stability of Chloroplast ndhA Transcripts.

Protein-mediated RNA stabilization plays profound roles in chloroplast gene expression. Genetic studies have indicated that chloroplast ndhA transcripts, encoding a key subunit of the NADH dehydrogenase-like complex that mediates photosystem I cyclic electron transport and facilitates chlororespiration, are stabilized by PPR53 and its orthologs, but the underlying mechanisms are unclear. Here, we report that CHLOROPLAST RNA SPLICING 2 (CRS2)-ASSOCIATED FACTOR (CAF) proteins activate SUPPRESSOR OF THYLAKOID FORMATION 1 (SOT1), an ortholog of PPR53 in Arabidopsis thaliana, enhancing their affinity for the 5' ends of ndhA transcripts to stabilize these molecules while inhibiting the RNA endonuclease activity of the SOT1 C-terminal SMR domain. In addition, we established that SOT1 improves the splicing efficiency of ndhA by facilitating the association of CAF2 with the ndhA intron, which may be due to the SOT1-mediated stability of the ndhA transcripts. Our findings shed light on the importance of PPR protein interaction partners in moderating RNA metabolism.

Resolution of Vaulted Biaryl Ligands via Borate Esters of Quinine and Quinidine.

Given the sudden and unexplained rise in the cost of (+)- and (-)-sparteine, an alternative method for the resolution of vaulted biaryls has been developed. This method involves the reaction of a racemic vaulted biaryl ligand with one equivalent of BH3·SMe2 and one equivalent of either quinine or quinidine. A precipitate then forms from the resulting mixture of diastereomeric borates as a result of differential solubilities. Hydrolysis of the precipitate then liberates the (S)-ligand in the case of quinine and the (R)-ligand in the case of quinidine, both with >99% ee. This method has been applied to 16 different vaulted biaryl ligands, including 10 whose preparation is described here for the first time. In addition, proof of principle has been demonstrated for the dynamic thermodynamic resolution of the vaulted biaryl ligands with this method in combination with a nonchiral copper(II) complex that can racemize the ligand.

Catalytic Asymmetric Epoxidation of Aldehydes with Two VANOL-Derived Chiral Borate Catalysts.

A highly diastereo- and enantioselective method for the epoxidation of aldehydes with α-diazoacetamides has been developed with two different borate ester catalysts of VANOL. Both catalytic systems are general for aromatic, aliphatic, and acetylenic aldehydes, giving high yields and inductions for nearly all cases. One borate ester catalyst has two molecules of VANOL and the other only one VANOL. Catalysts generated from BINOL and VAPOL are ineffective catalysts. An application is shown for access to the side-chain of taxol.

Pyro-Borates, Spiro-Borates, and Boroxinates of BINOL-Assembly, Structures, and Reactivity.

VANOL and VAPOL ligands are known to react with three equivalents of B(OPh)3 to form a catalytic species that contains a boroxinate core with three boron atoms, and these have proven to be effective catalysts for a number of reactions. However, it was not known whether the closely related BINOL ligand will likewise form a boroxinate species. It had simply been observed that mixtures of BINOL and B(OPh)3 were very poor catalysts compared to the same mixtures with VANOL or VAPOL. Borate esters of BINOL have been investigated as chiral catalysts, and these include meso-borates, spiro-borates, and diborabicyclo-borate esters. Borate esters are often in equilibrium, and their structures can be determined by stoichiometry and/or thermodynamics, especially in the presence of a base. The present study examines the structures of borate esters of BINOL that are produced with different stoichiometric combinations of BINOL with B(OPh)3 in the presence and absence of a base. Depending on conditions, pyro-borates, spiro-borates, and boroxinate species can be generated and their effectiveness in a catalytic asymmetric aziridination was evaluated. The finding is that BINOL borate species are not necessarily inferior catalysts to those of VANOL and VAPOL but that, under the conditions, BINOL forms two different catalytic species (a boroxinate and a spiro-borate) that give opposite asymmetric inductions. However, many BINOL derivatives with substitutents in the 3- and 3'-positions gave only the boroxinate species and the 3,3'-Ph2BINOL ligand gave a boroxinate catalyst that gives excellent inductions in the aziridination reaction. BINOL derivatives with larger groups in the 3,3'-position will not form either spiro-borates or boroxinate species and thus are not effective catalysts at all.

Enantioselective Palladium-Catalyzed Carbonylative Carbocyclization of Enallenes via Cross-Dehydrogenative Coupling with Terminal Alkynes: Efficient Construction of α-Chirality of Ketones.

An enantioselective PdII /Brønsted acid-catalyzed carbonylative carbocyclization of enallenes ending with a cross-dehydrogenative coupling (CDC) with a terminal alkyne was developed. VAPOL phosphoric acid was found as the best co-catalyst among the examined 28 chiral acids, for inducing the enantioselectivity of α-chiral ketones. As a result, a number of chiral cyclopentenones were easily synthesized in good to excellent enantiomeric ratio with good yields.

Review: Protein O-GlcNAcylation regulates DNA damage response: A novel target for cancer therapy.

The DNA damage response (DDR) safeguards the stable genetic information inheritance by orchestrating a complex protein network in response to DNA damage. However, this mechanism can often hamper the effectiveness of radiotherapy and DNA-damaging chemotherapy in destroying tumor cells, causing cancer resistance. Inhibiting DDR can significantly improve tumor cell sensitivity to radiotherapy and DNA-damaging chemotherapy. Thus, DDR can be a potential target for cancer treatment. Post-translational modifications (PTMs) of DDR-associated proteins profoundly affect their activity and function by covalently attaching new functional groups. O-GlcNAcylation (O-linked-N-acetylglucosaminylation) is an emerging PTM associated with adding and removing O-linked N-acetylglucosamine to serine and threonine residues of proteins. It acts as a dual sensor for nutrients and stress in the cell and is sensitive to DNA damage. However, the explanation behind the specific role of O-GlcNAcylation in the DDR remains remains to be elucidated. To illustrate the complex relationship between O-GlcNAcylation and DDR, this review systematically describes the role of O-GlcNAcylation in DNA repair, cell cycle, and chromatin. We also discuss the defects of current strategies for targeting O-GlcNAcylation-regulated DDR in cancer therapy and suggest potential directions to address them.

[Preliminary study of chitosan/pcDNA-EGFP-TGFbeta1 nanoparticles used in the transfection of synovial-derived mesenchymal stem cells].

The objective of this study is to explore the application possibility of chitosan/pcDNA-EGFP-TGFPbeta1 nanoparticles in the transfection of synovial-derived mesenchymal stem cells (SDMSCs). Chitosan/pcDNA-EGFP-TGFbeta1 nanoparticles were fabricated through method of ionic crosslinking. The SDMSCs were harvested from rabbit joints and cultured to passage 3. The SDMSCs were then transfected with chitosan/pcDNA-EGFP-TGFbeta1 nanoparticles. Scanning electronic microscope (SEM) was employed to detect the shape and diameter of the nanoparticles. The transfected SDMSCs were examined under the fluorescence microscope and detected through the flow cytometry (FCM). The SEM examination showed that the contour of the fabricated chitosan/pcDNA-EGFP-TGFbeta1 nanoparticles was round and its average diameter was 50 nm. After being cultured for 48 h, the SDMSCs transfected by chitosan/pcDNA-EGFP-TGFbeta1 nanoparticles could be detected under the fluorescence microscope, and the live SDMSCs could also be examined through FCM. The transfection rate was 8% - 10%. Therefore, it suggested that the chitosan/pcDNA-EGFP-TGFbeta1 nanoparticles fabricated through the method of ionic crosslinking could transfect the SDMSCs, but the transfection rate should be improved.

Poly-l-lactide-co-ε-caprolactone (PLCL) and poly-l-lactic acid (PLLA)/gelatin electrospun subacromial spacer improves extracellular matrix (ECM) deposition for the potential treatment of irreparable rotator cuff tears.

Biodegradable subacromial spacer implantation has become practicable for the treatment of irreparable rotator cuff tears (IRCT). However, the relative high degradation rate and inferior tissue regeneration properties of current subacromial spacer may lead to failure regards to long-term survival. It is reported that satisfactory clinical results lie in the surrounding extracellular matrix (ECM) deposition after implantation. This study aims to develop a biological subacromial spacer that would enhance tissue regeneration properties and results in better ECM deposition. Physicochemical properties were characterized on both poly-l-lactide-co-ε-caprolactone (PLCL) dip-coating spacer (monolayer spacer, MS) and PLCL dip-coating + Poly-l-Lactic Acid (PLLA)/Gelatin electrospun spacer (Bilayer Spacer, BS). Cytocompatibility, angiogenesis, and collagen inducibility were evaluated with tendon fibroblasts and endothelial cells. Ultrasonography and histomorphology were used to analyze biodegradability and surrounding ECM deposition after the implantation in vivo. BS was successfully fabricated with the dip-coating and electrospinning technique, based on the human humeral head data. In vitro studies demonstrated that BS showed a greater cytocompatibility, and increased secretion of ECM proteins comparing to MS. In vivo studies indicated that BS promoted ECM deposition and angiogenesis in the surrounding tissue. Our research highlights that BS exhibits better ECM deposition and reveals a potential candidate for the treatment of IRCT in future.

Higher incidence of diffuse Pigmented Villonodular Synovitis in patients with ruptured cruciate ligament: A case report.

INTRODUCTION: Pigmented Villonodular Synovitis (PVNS) is a kind of extremely rare and not easily diagnosed disease, while the occurrence following the anterior cruciate ligament (ACL) rupture is comparably high. CASE PRESENTATION: Here we reported 2 patients presenting knee swelling, pain, and giving away symptoms following a rupture of ACL history. Clinical and radiological findings were supportive of ACL rupture and PVNS, prompting the patient to undergo surgery. The synovium was completely removed with the help of an arthroscope. Reconstruction of the ruptured ACL was carried out a few months later. At the last follow-up visit, both the patients were doing well with no recurrence of pain, swelling, or give way sensation. DISCUSSION: The diagnosis of PVNS is often difficult because in the early stages, symptoms are often non-specific and pathological examination remains the gold standard for the diagnosis of PVNS. We have reviewed some of the previously reported literature on PVNS, suggesting that joint instability may be an important risk factor for PVNS and summarizing the treatment options for PVNS. CONCLUSION: More attention should be paid to the incidence of PVNS in patients with joint instability, particularly in patients with cruciate ligament injuries. Early and reliable stabilization of the joint may significantly prevent PVNS and ensure a better clinical outcome.

Acetate suppresses myocardial contraction via the short-chain fatty acid receptor GPR43.

The heart has high energy requirements, with an estimated 40%-60% of myocardial ATP production derived from the oxidation of fatty acids under physiological conditions. However, the effect of short-chain fatty acids on myocardial contraction remains controversial, warranting further research. The present study sought to investigate the effects and mechanisms of acetate, a short-chain fatty acid, on myocardial contraction in rat ventricular myocytes. Echocardiography and Langendorff heart perfusion were used to evaluate cardiac function. Cell shortening and calcium transient were measured in isolated cardiomyocytes. The patch-clamp method determined the action potential and L-type Ca2+ current in cardiomyocytes. Moreover, the expression of GPR43, a type of short-chain fatty acid receptors in cardiomyocytes was examined by immunofluorescent staining and Western blot. We demonstrated that acetate transiently reduced left ventricular developmental pressure in isolated Langendorff heart perfusion model, with no effect on stroke volume and cardiac output in vivo. In addition, acetate transiently and reversibly inhibited cardiomyocyte contraction and calcium transient. Acetate did not affect the action potential and L-type Ca2+ currents in cardiomyocytes. As a short-chain fatty acid receptor, GPR43 was expressed in rat cardiomyocytes. Furthermore, the GPR43 antagonist GLPG0974 prevented the acetate-induced inhibitory effect on myocardial contraction. We conclude that acetate transiently inhibits contraction via the short-chain fatty acid receptor GPR43 in cardiomyocytes.

Expression of the interleukin-21 and phosphorylated extracellular signal regulated kinase 1/2 in Kimura disease.

OBJECTIVE: To investigate the expressions of interleukin (IL)-21 and phosphorylated extracellular signal regulated kinase 1/2 (pERK1/2) in Kimura disease (KD) and to correlate the findings with clinical and prognostic variables. METHODS: Immunohistochemical analysis of IL-21 and pERK1/2 was performed in 18 cases of KD and five gender- and age-matched control samples. Clinical data were extracted and patients followed up for a mean period of 32.1 months. RESULTS: After a mean follow-up period of 32.1 months (range 1-102 months), recurrence was diagnosed as the end point for seven patients-that is, a 44% (7/16) cumulative recurrence rate. In comparison with gender- and age-matched controls, patients showed strong in situ expressions of IL-21 and pERK1/2, respectively (p<0.05). Patients with strong IL-21 staining intensity and overexpression of pERK1/2 had a lower recurrence rate than those with moderate staining intensity (p=0.049, p=0.019, respectively). However, differences were not statistically significant by gender, age, eosinophils, location, multiplicity, laterality, size, duration and primary outbreak. pERK1/2 was the independent prognostic factor (p=0.020), while age, gender, eosinophils, multiplicity, laterality, size, duration, primary outbreak and expression of IL-21 were not. CONCLUSIONS: This study suggests that the IL-21/pERK1/2 pathway is activated in KD, and pERK1/2 might be considered as a potential prognostic indicator in KD.

[Expressions of interleukin-21 and interleukin-22 in Kimura's disease].

OBJECTIVE: To investigate the expressions of interleukin (IL)-21 (IL-21) and IL-22 in patients with Kimura's disease (KD). METHODS: Expressions of IL-21 and IL-22 were examined immunohistochemically in 36 patients with KD and 7 normal controls. The integral absorbance (IA) of the two groups was compared. Meanwhile, clinical data were reviewed. RESULTS: The IA of IL-21 [M(Q): 1 373 418 (1 800 926)] and IL-22 [M(Q): 462 086(484 672)] in KD was significantly higher than those in normal controls [M(Q): 70 445(44 658), 51 599(71 241), P < 0.05]. The overexpression of IL-21 was significantly associated with pruritus (Z = -1.993, P < 0.05). Moreover, IL-21 was identified for disease recurrence (Z = -2.303, P < 0.05). There was a significant association between the expression of IL-22 and the number of affected sites (Z = -1.979, P < 0.05). In addition, IL-22 was significantly higher in the high-eosinophils group than in the low-eosinophils group (Z = -2.025, P < 0.05). There was no association between IL-21, IL-22 and age, gender, laterality, maximum size. CONCLUSIONS: IL-21 and IL-22 may be involved in the pathogenesis of KD.

[Reconstruction of zygomatic-facial massive defect using modified bilobed flap after resection of skin cancer].

OBJECTIVE: To investigate the clinical application of the modified bilobed flap in the reconstruction of zygomatic-facial massive defect after resection of skin cancer. METHODS: Between August 2009 and October 2011, 15 patients with skin cancer in the zygomatic-facial region underwent defect reconstruction using modified bilobed flaps after surgical removal. There were 12 males and 3 females, aged 52-78 years (mean, 64.1 years). The disease duration was 1-14 months (mean, 4.6 months). Among the patients, there were 11 cases of basal cell carcinoma and 4 cases of squamous cell carcinoma; 1 patient had infection and the others had no skin ulceration; and tumor involved the skin layer in all patients. According to TNM staging, 13 cases were rated as T2N0M2 and 2 cases as T3N0M3. The defect size ranged from 4.0 cm x 2.5 cm to 6.5 cm x 4.0 cm after cancer resection. The modified bilobed flaps consisting of pre-auricular flap and post-auricular flap was used to repair the defect after cancer resection. The size ranged from 4.0 cm x 2.5 cm to 6.5 cm x 4.0 cm of the first flap and from 3.0 cm x 2.0 cm to 5.0 cm x 3.0 cm of the second flap. RESULTS: Partial incision dehiscence occurred in 1 case, and was cured after dressing change; the flaps survived and incision healed primarily in the other cases. Fourteen patients were followed up 12-24 months (mean, 18.7 months). No recurrence was found, and the patients had no obvious face asymmetry or skin scar with normal closure of eyelid and facial nerve function. At last follow-up, the results were very satisfactory in 5 cases, satisfactory in 7 cases, generally satisfactory in 1 case, and dissatisfactory in 1 case. CONCLUSION: The pre- and post-auricular bilobed flaps could be used to reconstruct the massive defects in the zygomatic-facial region after resection of skin cancer.