Clinical characteristics of Danon disease / 中华心血管病杂志

Objective: To review the clinical data of 7 patients with Danon disease and analyze their clinical characteristics. Methods: The medical records of 7 patients with Danon disease, who were hospitalized in Peking Union Medical College Hospital of Chinese Academy of Medical Sciences from April 2008 to July 2021, were reviewed and summarized, of which 6 cases were diagnosed as Danon disease by lysosomal-associated membrane protein-2 (LAMP-2) gene mutation detection and 1 case was diagnosed by clinicopathological features. Clinical manifestations, biochemical indexes, electrocardiogram, echocardiography, skeletal muscle and myocardial biopsy and gene detection results were analyzed, and patients received clinical follow-up after discharge. Results: Six patients were male and average age was (15.4±3.5) years and the average follow-up time was (27.7±17.0) months. The main clinical manifestations were myocardial hypertrophy (6/7), decreased myodynamia (2/7) and poor academic performance (3/7). Electrocardiogram features included pre-excitation syndrome (6/7) and left ventricular hypertrophy (7/7). Echocardiography examination evidenced myocardial hypertrophy (6/7), and left ventricular dilatation and systolic dysfunction during the disease course (1/7). The results of skeletal muscle biopsy in 6 patients were consistent with autophagy vacuolar myopathy. Subendocardial myocardial biopsy was performed in 3 patients, and a large amount of glycogen deposition with autophagosome formation was found in cardiomyocytes. LAMP-2 gene was detected in 6 patients, and missense mutations were found in all these patients. During the follow-up period, implantable cardioverter defibrillator implantation was performed in 1 patient because of high atrioventricular block 4 years after diagnosis, and there was no death or hospitalization for cardiovascular events in the other patients. Conclusion: The main clinical manifestations of Danon disease are cardiomyopathy, myopathy and mental retardation. Pre-excitation syndrome is a common electrocardiographic manifestation. Autophagy vacuoles can be seen in skeletal muscle and myocardial pathological biopsies. LAMP-2 gene mutation analysis is helpful in the diagnose of this disease.

Identification of LAMP2 mutations in early-onset hypertrophic cardiomyopathy by targeted exome sequencing

X-linked dominant mutations in lysosome-associated membrane protein 2 (LAMP2) gene have been shown to be the cause of Danon disease, which is a rare disease associated with clinical triad of cardiomyopathy, skeletal myopathy, and mental retardation. Cardiac involvement is a common manifestation and is the leading cause of death in Danon disease. We report a case of a 24-month-old boy with hemizygous LAMP2 mutation who presented with failure to thrive and early-onset hypertrophic cardiomyopathy. We applied targeted exome sequencing and found a novel hemizygous c.692del variant in exon 5 of the LAMP2 gene, resulting a frameshift mutation p.Thr231Ilefs*11. Our study indicates that target next-generation sequencing can be used as a fast and highly sensitive screening method for inherited cardiomyopathy.

Effect of chaperone-mediated autophagy in MPP(+) -induced SH-SY5Y cells and interventional effect of puerarin / 中国中药杂志

<p><b>OBJECTIVE</b>To study the protective effect of puerarin on MPP(+) -induced SH-SY5Y cells by chaperone-mediated autophagy (CMA).</p><p><b>METHOD</b>The Parkinson's disease cell model was established by injuring SH-SY5Y cells with 1 mmol x L(-1) MPP+. The CCK-8 staining was adopted to detect the effect the puerarin of different concentrations on the survival rate of MPP(+)-induced SH-SYSY cells. The autophagosome formation was observed under transmission electron microscope. The AO staining showed the changes in the lysosome activity. RT-PCR was used to detect the changes in Lamp2a and Hsc70 mRNA expressions. The western blotting was adopted to test the expressions of Lamp2a, Hsc70 and alpha-synuclein protein in cells.</p><p><b>RESULT</b>Within the concentration range of 12. 5-50.0 micromol x L(-1), the pretreatment with puerain for 30 minutes could protect the injury of MPP+ in SH-SY5Y cells, and showed a certain dose-effect relationship. The AO staining and electron microscope showed the effect of puerain within the concentration range of 12.5-50.0 micromol x L(-1) on 1 mmol x L(-1) MPP(+)-induced SH-SY5Y cells; autophagosomes emerged in cells, and increased along with the rise in the puerarin dose. The results of the flow cytometry revealed that 50.0 micromol x L(-1) of puerarin could protect against the increase of the ROS level in 1 mmol x L(-1) MPP(+) -induced SH-SY5Y cells and prevent the oxidative injury. The results of RT-PCR and western blotting indicated that puerain within the concentration range of 12.5-50.0 micromol x L(-1) alleviated the MPP(+)-induced SH-SY5Y cell injury, and inhibited the accumulation of alpha-synuclein proteins in MPP(+) -induced SH-SY5Y cells by up-regulating Hsc70, Lamp2a mRNA and protein level.</p><p><b>CONCLUSION</b>Puerarin could protect against the MPP(+) -induced cell injury, whose protective mechanism may be related to the chaperone-mediated autophagy pathway of interventional molecules.</p>

Clinical characterization of patients with Danon disease / 中华心血管病杂志

<p><b>OBJECTIVE</b>To analyze the clinical characterization of Danon disease caused by the mutation of lysosome-associated membrane protein-2 (LAMP-2) gene.</p><p><b>METHODS</b>The clinical features, serum biochemical index, electrocardiogram and echocardiography data were retrospectively reviewed in 5 patients with genetically confirmed Danon disease. Mean follow-up period was (56 ± 6) months.</p><p><b>RESULTS</b>Five patients including 2 men and 3 women in 2 unrelated families with 2 novel mutations in the exon 3 (c.189-190TGdel) and 8 (c.1205Cdel) of the LAMP-2 gene were identified. All patients had cardiomyopathy, 1 patient (1/5) had skeletal myopathy, and none of the patients had mental retardation. The two male patients presented cardiac symptoms at the age of 9 and 10 years, respectively, and all female patients were asymptomatic. Biochemical analysis showed that serum creatine kinase and liver transaminase enzyme were increased in 2 patients (2/5). Abnormal electrocardiogram was observed in all patients, and 2 patients (2/5) had ventricular preexcitation. During the follow-up. One male patient died of cardiac failure at the age of 18 years and three months, and the symptoms of the other male patients rapidly developed with the evolution from hypertrophic cardiomyopathy into dilated cardiomyopathy. However, all female patients remained asymptomatic, and repeat echocardiography indicated only mild ventricular hypertrophy during follow up.</p><p><b>CONCLUSION</b>Patients with Danon disease mainly present hypertrophic cardiomyopathy, and sometimes presents with skeletal myopathy. The disorder occurs at early, age and progresses quickly and ends with poor prognosis in male patients. Other clinical features include elevations of serum creatine kinase and liver transaminase enzyme, ventricular preexcitation on electrocardiogram, and ventricular hypertrophy detected by echocardiography. Female patients remain asymptomatic till now in our cohort.</p>

Effect of chronic lead exposure on expression of autophagy-associated proteins in rat hippocampus / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the effects of chronic lead exposure on expression of autophagy-associated proteins in rat hippocampus.</p><p><b>METHODS</b>SD rats were randomly divided into three groups: control group was given distilled water, lead-exposed groups were given 0.5 g/L (low-dose) or 2.0 g/L(high-dose) lead acetate solution in drinking water. The rat pups started to drink the lead content water until 60 d maturity. The lead contents in blood and brain samples were analyzed by graphite furnace atomic absorption spectrophotometry. The expressions of Beclin 1, LC3, LAMP2 and cathepsin B proteins were detected by Western blot and immunohistochemistry.</p><p><b>RESULTS</b>Compared with control group, the contents of lead were significantly higher in blood and hippocampus samples in chronic lead-exposed rats (P<0.01). Western blot showed that the expression of Beclin 1 and LC3-II/LC3-I increased significantly in high dose lead-exposed group compared with control group (P<0.05 or P<0.001). The confocal laser immunostaining results demonstrated that increased immunofluorescence staining of cathepsin B in hippocampal neurons compared with control animals.</p><p><b>CONCLUSION</b>The disturbance of autophagy-lysosome signaling molecules might be partially contribute to neurotoxicity of chronic lead exposure.</p>

Immune responses in wild-type mice against prion proteins induced using a DNA prime-protein boost strategy / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To break immune tolerance to prion (PrP) proteins using DNA vaccines.</p><p><b>METHODS</b>Four different human prion DNA vaccine candidates were constructed based on the pcDNA3.1 vector: PrP-WT expressing wild-type PrP, Ubiq-PrP expressing PrP fused to ubiquitin, PrP-LII expressing PrP fused to the lysosomal integral membrane protein type II lysosome-targeting signal, and PrP-ER expressing PrP locating the ER. Using a prime-boost strategy, three-doses of DNA vaccine were injected intramuscularly into Balb/c mice, followed by two doses of PrP protein. Two weeks after the last immunization, sera and spleens were collected and PrP-specific humoral and cellular immune responses evaluated by ELISA and ELISPOT tests.</p><p><b>RESULTS</b>Higher levels of serum PrP antibodies were detected in mice vaccinated using the strategy of DNA priming followed by protein boosting. Of these, WT-PrP, Ubiq-PrP, and PrP-LII induced significantly higher humoral responses. ELISPOT tests showed markedly increased numbers of IFN-γ-secreting T cells in mice vaccinated using the strategy of DNA priming followed by protein boosting after stimulation with recombinant PrP23-90 and PrP23-231. PrP-ER induced the strongest T-cell response.</p><p><b>CONCLUSION</b>Prion vaccines can break tolerance to PrP proteins and induce PrP-specific humoral and cellular immune responses.</p>