Regioselective and Enantioselective Nickel-Catalyzed Intermolecular Reductive Coupling of Aliphatic Alkenes with Imines.

Unactivated aliphatic alkenes are particularly desirable as starting materials because they are readily accessible in large quantities, but the enantioselective intermolecular reductive coupling of unactivated alkenes with imines is challenging. In this paper, we report a method for nickel-catalyzed intermolecular reductive coupling reactions between aliphatic alkenes and imines to yield chiral amines with excellent enantioselectivities and good linear selectivities. The reaction conditions are compatible with a broad range of aliphatic alkenes, including those derived from bioactive molecules. The success of this method can be attributed to the use of newly developed monodentate chiral spiro phosphine ligands.

Organophosphine as an Alkyl Transfer Shuttle for the Direct ß-Alkylation of Chalcones Using Alkyl Halides.

We report an efficient alkyl transfer strategy for the direct ß-alkylation of chalcones using commercially available alkyl bromides as alkyl reagents. In this transformation, the ortho-phosphanyl substituent in the chalcones is crucial for controlling their reactivity and selectivity. It also serves as a reliable alkyl transfer shuttle to transform electrophilic alkyl bromides into nucleophilic alkyl species in the form of quaternary phosphonium salts and transfer the alkyl group effectively to the ß-position of the chalcones. This alkyl transfer strategy can be further extended to the alkenylation of ortho-phosphanyl benzaldehydes to assemble functionalized polyenes.

Phosphate stimulates myotube atrophy through autophagy activation: evidence of hyperphosphatemia contributing to skeletal muscle wasting in chronic kidney disease.

BACKGROUND: Accelerated muscle atrophy is associated with a three-fold increase in mortality in chronic kidney disease (CKD) patients. It is suggested that hyperphosphatemia might contribute to muscle wasting, but the underlying mechanisms remain unclear. Although evidence indicates that autophagy is involved in the maintenance of muscle homeostasis, it is not known if high phosphate levels can result in activation of autophagy, leading to muscle protein loss. METHODS: Immortalized rat L6 myotubes were exposed to a high concentration of phosphate, with or without autophagy inhibition. Myotube atrophy was examined by phase contrast microscopy. Autophagic activity was assessed by measuring the expression of microtubule-associated protein 1 light chain 3 (LC3) and p62 using quantitative real-time polymerase chain reaction and western blot. RESULTS: Phosphate induced cell atrophy in L6 myotubes in a dose- and time-dependent manner, and these responses were not associated with calcification or osteogenesis. Phosphate also dose- and time-dependently increased the LC3-II/LC3-I ratio. Inhibition of autophagy with wortmannin or knockdown of Atg5 significantly suppressed myotube atrophy caused by high phosphate concentration. CONCLUSIONS: High phosphate concentration induces muscle cell atrophy through the activation of autophagy. Targeting autophagy could be a therapeutic strategy for preventing muscle wasting caused by hyperphosphatemia.

Hepatitis B virus X protein modulates renal tubular epithelial cell-induced T-cell and macrophage responses.

Renal tubular epithelial cells (RTECs) have an active role in renal inflammation, functioning as antigen-presenting cells as they constitutively express major histocompatibility complex-II and co-stimulatory molecules that can activate T cells and macrophages. Previous studies indicate that inflammatory cell infiltration and tubulointerstitial fibrosis are present in renal biopsies from Hepatitis B virus (HBV)-associated glomerulonephritis (HBV-GN) patients. We hypothesized that disorder RTECs may be involved in the progression of HBV-GN. Here, we measured renal function and inflammatory cells infiltration in C57BL/6J-TgN mice, and data showed that in C57BL/6J-TgN mice HBV x protein (HBx) mainly deposited in RTECs, and CD4(+) T cells and macrophages infiltrated into the interstitium. In vitro HBx upregulated CD40 expression in RTECs. In HK-2/CD4(+) T cells co-culture system, we found that HBx-stimulated HK-2 cells could activate CD4(+) T cells, promote their proliferation, and lead to an imbalance of interleukin (IL)-4 and interferon-γ. In HK-2/macrophages co-culture system, we found that HBx-stimulated HK-2 cells also increased macrophage adherent capacity and promoted MCP-1 and tumor necrosis factor-α and IL-1ß secretion. These immune dysfunction may contribute to the pathogenesis of HBV-GN.

The role of the toll-like receptor TLR4 in hepatitis B virus-associated glomerulonephritis.

Toll-like receptor 4 (TLR4) plays an important role in innate immunity. The aim of our study was to detect the expression of TLR4 in HBV-associated glomerulonephritis (HBV-GN) and explore the pathogenesis of TLR4 in inhibition of HBV replication in kidney. Immunohistochemical methods were used to detect the distribution of immunoglobulin, HBsAg, HBcAg and TLR4. Because TLR4 was mainly distributed in renal tubules and interstitial spaces, we used human proximal tubular epithelial cells (HK-2) as target cells, which were cultured with HBV-DNA-positive serum. Cells were divided into four groups: A, a normal control group; B, an HBV-induced group; C, an HBV and 10 µg/ml LPS (TLR4-stimulating factor) group; and D, an HBV and 5 µg/ml CLI095 (TLR4 inhibitor) group. The morphology of HK-2 cells was observed by microscopy, and the expression of α-SMA was examined by immunofluorescence before and after culturing with HBV-DNA-positive serum. MTT was used to detect HK2 proliferation. The expression of TLR4 protein was detected by immunofluorescence and western-blotting assays, HBsAg and HBeAg levels in supernatants were measured by ELISA, and the expression of HBV-DNA was measured by semi-quantitative reverse transcription-PCR (RT-PCR). The immunohistochemical staining for TLR4 in the normal control group was negative. The expression of TLR4 in HBV-GN was significantly higher than in the HBV-antigen-positive and -negative primary glomerulonephritis (PGN) groups and was mainly distributed in renal tubules and the interstitial area, where the distribution of HBsAg had similar intensity. The expression of TLR4 was significantly associated with renal tubular and interstitial lesions. In an in vitro study with prolonged infection with HBV-DNA-positive serum, more irregularly shaped cells and fewer HK-2 were observed. The expression of α-SMA in the cytoplasm of HK-2 was significantly increased after HBV infection. Immunofluorescence results showed that almost no expression of TLR4 in HK2 cells cultured with normal serum (group A), while the expression of TLR4 was increased after HBV infection (group B). With increasing LPS concentration, the rate of the proliferation of HK2 cells, the levels of HBV-DNA in the supernatant, and the expression of HBsAg and HBeAg decreased. TLR4 was mainly expressed in HBV-GN in renal tubules and interstitial spaces and was significantly associated with renal tubular and interstitial lesions. The stimulation of TLR4 not only inhibited HBV replication but also inevitably induced immune injury to cells. Therefore, we speculate that TLR4 may be involved in an immune inflammatory reaction by inhibiting HBV replication in HK2 cells, which could have an antiviral effect during HBV infection in the kidney.

[Related factors and prognostic significance of intradialytic blood pressure variability in patients on maintenance hemodialysis].

OBJECTIVE: To evaluate intradialytic blood pressure variability (BPV) in patients on maintenance hemodialysis (MHD), and to investigate the correlated factors of BPV in MHD process and its correlation with prognosis. METHODS: Patients with end stage renal disease on MHD before January 1, 2009 were enrolled and analyzed retrospectively. Blood pressure at the first hemodialysis every quarter during January, 2009 and December, 2010 were recorded. The systolic pressure, diastolic pressure were calculated, and dialysis systolic and diastolic BPV were expressed with discrete coefficients. As for patients with follow-up time less than 2 years, blood pressures in evenly distributed 6-8 courses were used for calculation.Cardiovascular events and death were recorded and the follow-up was lasted till December 31, 2011. RESULTS: A total of 280 patients were enrolled, with intradialytic systolic BPV of 0.119 ± 0.029, and intradialytic diastolic BPV of 0.118 ± 0.028. Intradialytic systolic BPV in the elderly group (n = 114) was significantly higher than that in the younger group (n = 166) (0.126 ± 0.029 vs 0.114 ± 0.028, P = 0.012), while no significant difference was found in diastolic BPV (0.117 ± 0.031 vs 0.119 ± 0.025, P = 0.498). Intradialytic systolic BPV was used as variates in multivariable regression analysis, and results showed that age, systolic blood pressure before dialysis, intradialytic weight gain (IDWG) rate during dialysis and hemoglobin level were independent influential factors for intradialytic systolic BPV. The intradialytic diastolic BPV was used as variates in multivariable regression analysis, and results showed that IDWG rate and average dehydration volume were independent influential factors for intradialytic diastolic BPV. During 3 years of follow-up, 64 patients died (22.9%). The survival analysis showed that the dialysis systolic BPV elevation was associated with the mortality rate (P < 0.01). CONCLUSIONS: Older age, high systolic pressure before hemodialysis, high IDWG rate, and low hemoglobin level were independent risk factors of high intradialytic systolic BPV increase. Intradialytic high IDWG is an independent risk factor of high intradialytic diastolic BPV increase in patients on MHD. Intradialytic systolic BPV increase is associated with all-cause mortality in patients on MHD.

[Autophagy-lysosome pathway in skeletal muscle of diabetic nephropathy rats and the effect of low-protein diet plus α-keto acids on it].

OBJECTIVE: To explore the regulation of autophagy-lysosome pathway (ALP) in skeletal muscle of diabetic nephropathy and examine the effect of low protein diet plus α-keto acid on ALP. METHODS: A total of 45 24-week-old Goto-Kakizaki rats were randomized to receive normal protein (22%) diet (NPD), low-protein (6%) diet (LPD) or low-protein (5%) plus α-keto acids (1%) diet (Keto) (n = 15 each). Wistar control rats had a normal protein diet. The mRNA and protein levels of ALP markers LC3B, Bnip3, Cathepsin L in soleus muscle were evaluated at 48 weeks. Electron microscopy was used to confirm the changes of autophagy. RESULTS: Compared with CTL group, the mRNA levels of LC3B, Bnip3, Cathepsin L in soleus muscle of rats on NPD were higher, and protein levels of LC3B-I, LC3B-II, Bnip3, Cathepsin L in soleus muscle of rats on NPD also higher than CTL group (0.82 ± 0.33 vs 0.25 ± 0.07, 0.76 ± 0.38 vs 0.20 ± 0.12, 1.25 ± 0.30 vs 0.56 ± 0.19, 1.29 ± 0.40 vs 0.69 ± 0.20). The mRNA levels of LC3B, Bnip3 and Cathepsin L in LPD group were slightly lower, compared with NPD group. However there was no statistical significance. Similarly the protein levels of LC3B-I, LC3B-II, Bnip3 and Cathepsin L in LPD group were slightly lower with no statistical significance. In contrast, the mRNA levels of LC3B, Bnip3 and Cathepsin L were greatly lower in Keto group in comparison with NPD and LPD. And protein levels of LC3B-I, LC3B-II, Bnip3 and Cathepsin L were also greatly lower in Keto group in comparison with NPD and LPD. Additionally, autophagosome or auto-lysosome was found in NPD and LPD groups by electron microscopy. CONCLUSIONS: ALP is activated in skeletal muscle of diabetic nephropathy rats. And low protein plus α-keto acid decrease the activation of ALP and improve muscle wasting.

Dearomative Periphery Modification of Quinolinium Salts to Assemble Ring-Encumbered Pyrrolidine-Tetrahydroquinoline Polycycles.

We report an unexpected dearomative periphery modification strategy for transforming quinolinium salts into structurally crowded pyrrolidine-tetrahydroquinoline polycyclic systems with complete regio- and diastereoselectivity. Importantly, the reaction pathway was regulated by simply tuning the substituents, achieving substituent-directed divergent synthesis. The notable features of this transformation include readily available starting materials, green conditions, a simple workup procedure, high bond- and ring-forming efficiency, and substituent-directed diverse synthesis.

[The expression and role of Toll receptor 4 in renal tubular epithelial cells in hepatitis B virus infection].

OBJECTIVE: To explore the expression and role of Toll receptor 4 (TLR4) in human proximal tubular epithelial cell line HK-2, infected by HBV. METHODS: The serum of HBV DNA copies between 10(7) - 10(8)/ml was collected. Before and after infected by HBV DNA positive serum, the HK-2 cells' morphology and the expression of α-smooth muscle actin (α-SMA) were observed by microscopy and immunofluorescence, and the effects of different concentrations of lipopolysaccharides (LPS, TLR4-stimulating factor) and CLI-095 (TLR4 Inhibitor) on the proliferation rate of HK-2 cells were observed by MTT assays. After HBV serum and 10 µg/ml LPS and 5 µl/ml CLI-095 acted on HK-2 cells, TLR4 protein expression was measured by immunofluorescence and Western-blotting assay, and HBsAg and HBeAg in cell culture medium were detected by ELISA, and HBV DNA copies by fluorescence quantitative PCR. RESULTS: The longer HBV infected HK-2 cells, the more irregular of the cells' shape, the fewer number of the cells were left. But compared with HBV infected after 24 hours, α-SMA was more expressed after HBV infected 12 hours.After infected by HBV serum in 24 hours, HK-2 cells' proliferation rate was positively correlation in a dose range of LPS, but was negatively correlated with the CLI-095 (P < 0.05). The levels of HBsAg and HBeAg in cell culture medium were largest when the LPS concentration was at 10 µg/ml and CLI-095 at 5 µg/ml. The expression of TLR4 significantly increased in HK-2 cells treated with LPS compared with those with CLI-095, but HBV DNA levels and HBsAg and HBeAg expression levels were lower. CONCLUSIONS: HBV infection may promote cell transdifferentiation and cell injury. The stimulation of HK-2 infected with HBV by LPS may upregulate the expression of TLR4 and reduce the copies of HBV DNA.

[Toll-like receptor 4 deposition and its significance in hepatitis B virus associated nephropathy].

OBJECTIVE: To investigate the expression and distribution of Toll-like receptor 4 (TLR4) in renal tissue of HBV associated nephropathy (HBV-GN) and its role in the pathogenesis and clinical manifestations of HBV-GN. METHODS: Renal tissues were sampled from 48 HBV-GN patients confirmed by renal biopsy and 154 non-HBV-GN patients. The distribution of TLR4 in renal tissue and the relationship between the distribution of TLR4 and HBsAg were detected by immunohistochemistry. Integrating case record, correlations between the expression of TLR4 with clinical parameters including pathology, glomeruli, kidney tubules lesions, renal interstitial inflammatory infiltration and blood serum HBV were analyzed. RESULTS: TLR4 mainly distributed in the renal tubular epithelial cells and interstitial areas as brownish red and granular, which was in consistent with HBsAg distribution. The TLR4 positive rate and score in HBV-GN group were higher than those in non-HBV-GN group (P < 0.05). TLR4 positive score was slightly higher in mesangial proliferative glomerulonephritis group and focal segmental glomerulosclerosis group, which had no significant difference (P > 0.05). Kidney tubules lesions were strongly associated with TLR4 expression (r = 0.748, P < 0.001) which increased with aggravation of renal interstitial fibrosis (r = 0.569, P < 0.001), tubular atrophy (r = 0.577, P < 0.001) and inflammatory cell infiltration (r = 0.684, P < 0.001). No obvious correlation with glomeruli lesions was observed (r = 0.293, P = 0.053). Negative correlation could be seen between TLR4 and the renal function (R(2) = 0.784), systolic blood pressure (R(2) = 0.869), high sensitivity C-reactive protein (R(2) = 0.979) and urinary protein (R(2) = 0.615) by regression analysis. Other clinical parameters had no statistical significances. CONCLUSIONS: The expression of TLR4 is abnormal in the renal tissue of HBV-GN patients, mainly in renal tubular epithelial cells and interstitial, which is consistent with the distribution of HBsAg. Its intensity is closely related with renal interstitial lesions, renal function changes and inflammatory cell infiltration. A speculation, that HBV can promote abnormal expression of TLR4 in renal tissues of HBV-GN which may be involved in the lesion progress of HBV-GN, is made upon our study.

Calpain 6 inhibits autophagy in inflammatory environments: A preliminary study on myoblasts and a chronic kidney disease rat model.

A non­classical calpain, calpain 6 (CAPN6), can inhibit skeletal muscle differentiation and regeneration. In the present study, the role of CAPN6 in the regulation of the autophagy of myoblasts in vitro was investigated. The underlying molecular events and the CAPN6 level in atrophic skeletal muscle in a rat model of chronic kidney disease (CKD) were also investigated. In vitro, CAPN6 was overexpressed, or knocked down, in rat L6 myoblasts to assess autophagy and related gene expression and co­localization. Subsequently, myoblasts were treated with a mixture of cytokines, and relative gene expression and autophagy were assessed. A rat model of CKD for muscle atrophy was established, and blood chemical level and the expression of CAPN6 in muscle were assessed. The data revealed that the knockdown of CAPN6 in rat myoblasts resulted in increased microtubule­associated protein 1 light chain 3 (LC3) levels, while its overexpression decreased LC3 levels and impaired autophagy. Additionally, it was observed that the co­localization of mammalian target of rapamycin (mTOR) and lysosomal­associated membrane protein 1 (LAMP1), a lysosomal marker, proteins was increased. In addition, mTOR, Raptor and α­tubulin (a marker of microtubules) increased in the CAPN6 overexpression group. However, inflammatory cytokines, such as interleukin (IL)­6, tumor necrosis factor (TNF)­α, interferon (INF)­Î³ and lipopolysaccharides upregulated CAPN6 expression, inhibited L6 myoblast autophagy and stabilized mTOR activity. Furthermore, the animal model successfully mimicked human disease as regards an increase in body weight, and a reduction in muscle mass, cross­sectional area and blood biomarker concentrations; a slight increase in CAPN6 mRNA and protein levels in muscles was observed. Finally, the data of the present study suggested that CAPN6 reduced autophagy via the maintenance of mTOR signaling, which may play a role in CKD­related muscle atrophy. However, future studies are required to determine whether CAPN6 may be used as an intervention target for CKD­related skeletal muscle atrophy.

CKD autophagy activation and skeletal muscle atrophy-a preliminary study of mitophagy and inflammation.

BACKGROUND/OBJECTIVES: Long-lived proteins and organelles, such as mitochondria and the sarcoplasmic reticulum, are degraded by autophagy. However, the specific role of autophagy in chronic kidney disease (CKD) muscle atrophy is still undefined. SUBJECTS/METHODS: This was a cross-sectional study with 20 subjects and 11 controls. Autophagy induction was studied in human skeletal muscle biopsies from CKD patients and controls by comparing the cross-sectional areas of muscle fibers, protein, and mRNA expression of autophagy-related genes and the appearance of autophagosomes. RESULTS: The cross-sectional area of muscle fibers was decreased in CKD patients as compared with the control group. CKD was associated with activated autophagy and mitophagy, as measured by the elevated mRNA and protein expression of BNIP3, (microtubule-associated proteins 1 A/1B light chain 3, also MAP1LC3) LC3, p62, PINK1, and PARKIN in the skeletal muscle and isolated mitochondria of the CKD group. Electron microscopy and immunohistofluorescence analysis showed mitochondrial engulfment by autophagosomes. Mitophagy was further demonstrated by the colocalization of LC3 and p62 puncta with the mitochondrial outer membrane protein TOM20. In addition, degradative FOXO3 (Forkhead box O3) was activated and synthetic mTOR (mammalian target of rapamycin) was inhibited, whereas the upstream mediators VPS34 (class III PI3-kinase) and AKT (protein kinase B, PKB) were activated in CKD patients. CONCLUSIONS: Hyperactive autophagy and mitophagy may play important roles in CKD muscle atrophy. Autophagy was activated by FOXO3 translational factors in the skeletal muscle tissues of CKD patients, which maybe a new way of intervention for CKD muscle atrophy.

Helicobacter pylori cytotoxin-associated gene A impairs the filtration barrier function of podocytes via p38 MAPK signaling pathway.

Helicobacter pylori (Hp) specific antigens were found deposited in the glomeruli in some kidney diseases. However, the underlying molecular mechanisms remain to be elucidated. The aim of this study was to investigate the effect of cytotoxin associated gene A protein (CagA), a key virulence factor of Hp, on mouse podocytes. Cells were cultured and treated with recombinant CagA protein. The expression of the tight junction protein ZO-1 and p38 MAPK signaling pathway activation were measured with real-time RT-PCR and western blotting. The filtration barrier function of podocytes was evaluated with albumin influx assay. CagA decreased the expression and membrane distribution of ZO-1, impaired the filtration barrier function of podocytes, while activating p38 MAPK signaling pathway in these cells. Selective p38 MAPK inhibition partly prevented CagA-induced filtration barrier dysfunction of podocytes through ameliorating ZO-1 downregulation. Taken together, the results suggested that CagA, at least via p38 MAPK signaling pathway, may induce podocyte injury. Anti-Hp therapy may be beneficial for the treatment of kidney diseases related to Hp antigen deposition.

Effect of a low-protein diet supplemented with keto-acids on autophagy and inflammation in 5/6 nephrectomized rats.

Ketoacids (KA) are known to preserve muscle mass among patients with chronic kidney disease (CKD) on a low-protein diet (LPD). The present study was to compare the effects of KA supplemented diet therapy in autophagy and inflammation in CKD rats' skeletal muscle. Rats with 5/6 nephrectomy were randomly divided into three groups and fed with either 11 g/kg/day protein [normal-protein diet (NPD)], 3 g/kg/day protein (LPD) or 3 g/kg/day protein which including 5% protein plus 1% KA (LPD + KA) for 24 weeks. Sham-operated rats with NPD intake were used as control. LPD could improve body weight, gastrocnemius muscle mass, as well as gastrocnemius muscle cross-sectional area, with the effect being more obvious in the LPD + KA group. The autophagy marker LC3 (microtubule-associated protein 1 light chain 3), p62, Parkin and PTEN induced putative kinase 1 (PINK1) were significantly attenuate in LPD + KA group than LPD group. LPD + KA group had the lower total mtDNA (mitochondiral DNA) and cytosol mtDNA, NACHT-PYD-containing protein 3 (NALP3) inflammasome than LPD group, but its reactive oxygen species (ROS), caspase-1 and apoptosis-associated speck-like protein containing a CARD (ASC) level was higher. Immunoblotting showed IL-1ß (interleukin-1-beta) was lower in LPD and LPD + KA group than the NPD group, but IL-18 showed no significant difference among control and CKD group; toll-like receptor signalling-dependent IL-6 was higher in LPD + KA group than LPD group, but tumor necrosis factor-α (TNF-α) was not significantly changed between LPD + KA and LPD group. Systematic changes of the four cytokines were different from that of the tissue. Although LPD + KA could further ameliorate-activated autophagy than LPD, its effect on the activated inflammation state in CKD was not distinctly. Further study is still required to explore the method of ameliorating inflammation to provide new therapeutic approaches for CKD protein energy wasting (PEW).