Effect of acid sphingomyelinase on nonalcoholic fatty liver disease via PPARα- PGC-1α pathway / 中国药理学通报

Aim To investigate the effects of acid sphingomyelinase(ASMase)on high-fat induced nonalcoholic fatty liver disease in mice and its regulation of PPARα- PGC-1α pathway. Methods ASMase knockout mice based on C57BL/6 background were constructed. Closed group heterozygotes were obtained through hybridized with wild-type mice(ASMase+/-),together with the littermate WT mice were prepared for NAFLD model in this study. The experiment was divided into four groups:WT+Chow:the WT mice were fed with normal diet for 12 weeks; WT+HFD:the WT mice were fed with high-fat diet for 12 weeks; ASMase+/-+Chow:the ASMase+/- mice were fed with normal diet for 12 weeks; ASMase+/- +HFD:the ASMase+/- mice were fed with high fat diet for 12 weeks. Biochemical method was used to detect serum TC,TG and liver TC,TG contents and liver function such as ALT and AST. Oil red staining,HE staining,Masson staining and Sirius red staining were performed to detect liver lipid accumulation,hepatocyte morphology and liver fibrosis. AmplexTM red sphingomyelinase kit was applied to detect ASMase activity. Western blot was performed to detect protein expressions of ASMase,PPARα,PGC-1α and CPT1. Results WT+HFD group displayed hypercholesterolemia and liver dysfunction. Levels of liver triglyceride(TG)were significantly higher than those in WT+Chow group(P<0.05 or P<0.01). Meanwhile,the hepatocytes showed marked steatosis,balloon-like changes,and fibrosis. Protein expression and activity of ASMase in liver increased significantly(P<0.01 or P<0.001),whereas CPT1,PPARα and PGC-1α expressions were not statistically significant compared with matched control group. Heterozygously ASMase-deficient mice reduced the elevated liver TG induced by HFD,as well as improving balloon-like changes and liver fibrosis. Furthermore,the expressions of PPARα,PGC-1α and CPT1 were up-regulated in ASMase+/- +HFD mice compared with WT+Chow group.Conclusions ASMase promotes hepatic steatosis and fibrosis,which may be related to its inhibition of PPARα-PGC-1α pathway.

Advances in the diagnosis of acid sphingomyelinase deficiency / 中国医师杂志

Acid sphingomyelinase deficiency (ASMD), also known as type A and B Niemann-Pick disease, is a group of intra-lysosomal lipid storage diseases caused by mutations in the SMPD1 gene that decrease acid sphingomyelinase activity or even cause deletion, resulting in abnormal deposition of sphingolipids. This disease can be diagnosed by bone marrow aspiration, pathological biopsy, acid sphingomyelinase activity measurement and SMPD1 gene testing. In recent years, with the rapid progress of molecular diagnostic techniques, new insights have been gained in the laboratory diagnosis of ASMD by means of molecular genetic tests, biomarkers and acid sphingomyelinase activity assay. This article will review the diagnostic progress of ASMD, aiming to reduce the misdiagnosis and leakage of the disease and improve the clinicians′ understanding of the disease.

Effect of desipramine on apoptosis and endoplasmic reticulum stress in atherosclerotic plaque of rabbits / 中国药理学通报

Aim: To investigate the effect of desipramine (DES) on apoptosis and endoplasmic reticulum stress(ERS) in atherosclerotic model of rabbits. Methods: The rabbit model of atherosclerosis (AS) was established through abdominal aorta balloon injury and high fat diets for 12 weeks. They were divided into high-fat diet(HFD) group and HFD + DES group randomly. The same numbers of healthy rabbits with chow diet were divided randomly into normal control (NC) group and DES group. All interventions were given for the last 4 weeks. At the end of week 12, serum lipid was tested by conventional method. Plasma ox-LDL was measured by ELISA. Plasma and arterial acid sphingomyelinase(ASM) activity and ceramide levels were detected by UPLC analysis. Cell apoptosis in abdominal aorta was measured by TUNEL staining. Expression of GRP78 and CHOP proteins were detected by Western blot. Results: On the one hand, DES had no effect on serum lipid profiles including TG, TC, HDL-C.LDL-C and ox-LDL levels compared with either healthy or atherosclerosis rabbits. On the other hand, DES inhibited ASM and ceramide levels both in plasma and aorta, and decreased apoptotic cells and proteins of GRP78 and CHOP expression in abdominal aorta. Conclusions: DES attenuates AS via inhibition of ASM, down-regulating ceramide, attenuating ERS and thus reducing the apoptosis of AS plaques.

Analysis of the mutations of SMPD1 gene in Niemann-Pick disease / 临床儿科杂志

Objectives To study the molecular genetics of Niemann-Pick's disease (NPD), and its implication in the diagnosis of NPD. Methods The clinical data and blood samples of three unrelated families were collected. The genomic DNA was extracted from peripheral blood. The six coding exons and their lfanking intronic sequences of SMPD1 gene in all members of three pedigrees were ampliifed by polymerase chain reaction (PCR). The SMPD1 gene sequencing results were compared with the normal sequence from Genbank to identify possible causative mutations. The ampliifcation products of exons where mutations were located were cloned into TA vector for further conifrmation. Results Family 1 proband had homozygous T107C mutation and the parents had heterozygous T107C mutation. The homozygous delete mutation (c.108-113delGCTGGC) was detected and conifrmed by TA cloning in all members of family 2 and 3. The 20 normal control members did not have this delete mutation. Conclusions The genetic basis of NPD in the proband of family 1 is the homozygous T107C mutation in SMPD1 gene, while parents in family 1 are carriers of recessive T107C mutation. The homozygous mutation c.108-113delGCTGGC exists in SMPD1 gene in all members of the family 2 and 3. This delete mutation is considered to be genetic polymorphism.

Analysis of Acid Sphingomyelinase Activity in Dried Blood Spots Using Tandem Mass Spectrometry

BACKGROUND: Niemann Pick disease (NP) is a rare, lysosomal storage disorder due to deficiency of the intra-lysosomal enzyme acid sphingomyelinase (ASM) resulting in intracellular accumulation of sphingomyelin. We evaluated a tandem mass spectrometry (MS/MS) method to analyze ASM activity in dried blood spots (DBS) that may be suitable for laboratory diagnosis of NP including high throughput screening of at-risk populations and potentially for newborn screening. METHODS: ASM activity was measured in 3.2 mm punches from DBS. The eluate was incubated with the ASM substrate (N-Hexanoyl-D-erythro-sphingosylphosphorylcholine [C6-sphingomyelin (C29H59N2O6P)]) and an internal standard (N-butyroyl-D-erythro-sphingosine [C4-ceramide (C22H43NO3)]). ASM product and IS were analyzed using MS/MS in multiple reaction monitoring mode for transitions m/z 370.6>264.3 (ASM internal standard) and m/z 398.6>264.3 (ASM product). RESULTS: ASM activities were stable for up to 2 months at or below 4degrees C. Position of the punch in the DBS and/or hematocrit of the DBS had a limited effect on ASM activities. Both intra- and inter-assay variability were below 10%. There was no carry-over. The median ASM activity in 2,085 newborn infants was 9.5 micromol/h/L (mean 10.6) with a SD of 5.06 micromol/h/L. Six of 2,085 (0.3%) infants were found to have ASM activities below the cut-off of 2.5 micromol/h/L. ASM activities were below the cut-off level in all 10 previously diagnosed cases with NP (range: 0.16 to 2.08 micromol/h/L). CONCLUSIONS: This MS/MS method for the measurement of ASM activity in DBS is robust and suitable for laboratory diagnosis of NP.

Analysis of Acid Sphingomyelinase Activity in Dried Blood Spots Using Tandem Mass Spectrometry

BACKGROUND: Niemann Pick disease (NP) is a rare, lysosomal storage disorder due to deficiency of the intra-lysosomal enzyme acid sphingomyelinase (ASM) resulting in intracellular accumulation of sphingomyelin. We evaluated a tandem mass spectrometry (MS/MS) method to analyze ASM activity in dried blood spots (DBS) that may be suitable for laboratory diagnosis of NP including high throughput screening of at-risk populations and potentially for newborn screening. METHODS: ASM activity was measured in 3.2 mm punches from DBS. The eluate was incubated with the ASM substrate (N-Hexanoyl-D-erythro-sphingosylphosphorylcholine [C6-sphingomyelin (C29H59N2O6P)]) and an internal standard (N-butyroyl-D-erythro-sphingosine [C4-ceramide (C22H43NO3)]). ASM product and IS were analyzed using MS/MS in multiple reaction monitoring mode for transitions m/z 370.6>264.3 (ASM internal standard) and m/z 398.6>264.3 (ASM product). RESULTS: ASM activities were stable for up to 2 months at or below 4degrees C. Position of the punch in the DBS and/or hematocrit of the DBS had a limited effect on ASM activities. Both intra- and inter-assay variability were below 10%. There was no carry-over. The median ASM activity in 2,085 newborn infants was 9.5 micromol/h/L (mean 10.6) with a SD of 5.06 micromol/h/L. Six of 2,085 (0.3%) infants were found to have ASM activities below the cut-off of 2.5 micromol/h/L. ASM activities were below the cut-off level in all 10 previously diagnosed cases with NP (range: 0.16 to 2.08 micromol/h/L). CONCLUSIONS: This MS/MS method for the measurement of ASM activity in DBS is robust and suitable for laboratory diagnosis of NP.

The role of acid sphingomyelinase in the development and progression of tumors and its application value / 肿瘤

Acid sphingomyelinase (aSMase) is an important enzyme in sphingolipid metabolism. Studies concerning the relationship between aSMase and tumor are relatively rare. However, the relationship between aSMase and the development and progression of tumors has already been demonstrated in previously published research. In this review, the mechanism of aSMase activation and the role of aSMase in the development and progression of tumors as well as its application value are summarized. Copyright © 2012 by TUMOR.

Potential role of acid sphingomyelinase in environmental health / 中南大学学报(医学版)

Acid sphingomyelinase (ASM) is one enzyme responsible for the production of ceramide via the hydrolysis of sphingomyelin.Recent findings have revealed the important role of ASM in the initiation of ceramide-induced cell apoptosis,as well as in the pathophysiology of many common diseases (e.g.cardiovascular diseases,diabetes,pulmonary diseases,and neurological diseases).Other studies have also shown that ASM activation may occur through the production of reactive oxygen species (ROS) and reactive nitrogen species (RNS),as well as by inflammatory mechanisms that may be induced by environmental and occupational stresses.ASM activation,in turn,may create excess or abnormally distributed ceramides,which could lead to tissue and organ injuries,including to the pulmonary,liver,kidney,and nervous systems.This review will discuss the basic biology of ASM and focus on the role and regulation of ASM in environmental stress responses.We propose that ASM activation is an important factor in environmental health,and that ASM-based therapeutics may have a key role in preventing environmental-induced tissue injury.