OBJECTIVE: To explore the clinical features, lysosomal enzymatic [acid α-glucosidase (GAA)] activities and genetic variants in a child with late-onset Pompe disease (LOPD). METHODS: Clinical data of a child who had presented at the Genetic Counseling Clinic of West China Second University Hospital in August 2020 was retrospectively analyzed. Blood samples were collected from the patient and her parents for the isolation of leukocytes and lymphocytes as well as DNA extraction. The activity of lysosomal enzyme GAA in leukocytes and lymphocytes was analyzed with or without addition of inhibitor of GAA isozyme. Potential variants in genes associated with neuromuscular disorders were analyzed, in addition with conservation of the variant sites and protein structure. The remaining samples from 20 individuals undergoing peripheral blood lymphocyte chromosomal karyotyping were mixed and used as the normal reference for the enzymatic activities. RESULTS: The child, a 9-year-old female, had featured delayed language and motor development from 2 years and 11 months. Physical examination revealed unstable walking, difficulty in going upstairs and obvious scoliosis. Her serum creatine kinase was significantly increased, along with abnormal electromyography, whilst no abnormality was found by cardiac ultrasound. Genetic testing revealed that she has harbored compound heterozygous variants of the GAA gene, namely c.1996dupG (p.A666Gfs*71) (maternal) and c.701C>T (p.T234M) (paternal). Based on the guidelines from the American College of Medical Genetics and Genomics, the c.1996dupG (p.A666Gfs*71) was rated as pathogenic (PVS1+PM2_Supporting+PM3), whilst the c.701C>T (p.T234M) was rated as likely pathogenic (PM1+PM2_Supporting+PM3+PM5+PP3). The GAA in the leukocytes from the patient, her father and mother were respectively 76.1%, 91.3% and 95.6% of the normal value without the inhibitor, and 70.8%, 112.9% and 128.2% of the normal value with the inhibitor, whilst the activity of GAA in their leukocytes had decreased by 6 ~ 9 times after adding the inhibitor. GAA in lymphocytes of the patient, her father and mother were 68.3%, 59.0% and 59.5% of the normal value without the inhibitor, and 41.0%, 89.5% and 57.7% of the normal value with the inhibitor, the activity of GAA in lymphocytes has decreased by 2 ~ 5 times after adding the inhibitor. CONCLUSION The child was diagnosed with LOPD due to the c.1996dupG and c.701C>T compound heterozygous variants of the GAA gene. The residual activity of GAA among LOPD patients can range widely and the changes may be atypical. The diagnosis of LOPD should not be based solely on the results of enzymatic activity but combined clinical manifestation, genetic testing and measurement of enzymatic activity.
Humans ; Child ; Male ; Female ; Glycogen Storage Disease Type II/pathology* ; Retrospective Studies ; alpha-Glucosidases/genetics* ; Mothers ; Lysosomes/pathology* ; Mutation

We have previously reported that Cystatin C (CysC) is a pivotal mediator in the neuroprotection induced by hyperbaric oxygen (HBO) preconditioning; however, the underlying mechanism and how CysC changes after stroke are not clear. In the present study, we demonstrated that CysC expression was elevated as early as 3 h after reperfusion, and this was further enhanced by HBO preconditioning. Concurrently, LC3-II and Beclin-1, two positive-markers for autophagy induction, exhibited increases similar to CysC, while knockdown of CysC blocked these elevations. As a marker of autophagy inhibition, p62 was downregulated by HBO preconditioning and this was blocked by CysC knockdown. Besides, the beneficial effects of preserving lysosomal membrane integrity and enhancing autolysosome formation induced by HBO preconditioning were abolished in CysC rats. Furthermore, we demonstrated that exogenous CysC reduced the neurological deficits and infarct volume after brain ischemic injury, while 3-methyladenine partially reversed this neuroprotection. In the present study, we showed that CysC is biochemically and morphologically essential for promoting autophagic flux, and highlighted the translational potential of HBO preconditioning and CysC for stroke treatment.
Animals ; Autophagy ; physiology ; Beclin-1 ; metabolism ; Brain ; metabolism ; pathology ; Brain Ischemia ; metabolism ; pathology ; therapy ; Cystatin C ; genetics ; metabolism ; Disease Models, Animal ; Gene Expression ; Gene Knockdown Techniques ; Hyperbaric Oxygenation ; Lysosomes ; metabolism ; pathology ; Male ; Microtubule-Associated Proteins ; metabolism ; Neurons ; metabolism ; pathology ; Neuroprotection ; physiology ; Oxygen ; therapeutic use ; Random Allocation ; Rats, Sprague-Dawley ; Rats, Transgenic ; Reperfusion Injury ; metabolism ; pathology ; therapy

The clinical treatment of joint contracture due to immobilization remains difficult. The pathological changes of muscle tissue caused by immobilization-induced joint contracture include disuse skeletal muscle atrophy and skeletal muscle tissue fibrosis. The proteolytic pathways involved in disuse muscle atrophy include the ubiquitin-proteasome-dependent pathway, caspase system pathway, matrix metalloproteinase pathway, Ca-dependent pathway and autophagy-lysosomal pathway. The important biological processes involved in skeletal muscle fibrosis include intermuscular connective tissue thickening caused by transforming growth factor-β1 and an anaerobic environment within the skeletal muscle leading to the induction of hypoxia-inducible factor-1α. This article reviews the progress made in understanding the pathological processes involved in immobilization-induced muscle contracture and the currently available treatments. Understanding the mechanisms involved in immobilization-induced contracture of muscle tissue should facilitate the development of more effective treatment measures for the different mechanisms in the future.
Atrophy ; Autophagy ; Calcium ; metabolism ; Caspases ; metabolism ; Connective Tissue ; metabolism ; pathology ; Contracture ; etiology ; metabolism ; pathology ; therapy ; Fibrosis ; Humans ; Immobilization ; adverse effects ; Joints ; Lysosomes ; metabolism ; Matrix Metalloproteinases ; metabolism ; Muscle, Skeletal ; metabolism ; pathology ; Proteasome Endopeptidase Complex ; metabolism ; Proteolysis ; Signal Transduction ; physiology ; Transforming Growth Factor beta1 ; metabolism ; Ubiquitin ; metabolism

Lysosomes are degradation and signaling centers within the cell, and their dysfunction impairs a wide variety of cellular processes. To understand the cellular effect of lysosome damage, we screened natural small-molecule compounds that induce lysosomal abnormality using Caenorhabditis elegans (C. elegans) as a model system. A group of vobasinyl-ibogan type bisindole alkaloids (ervachinines A-D) were identified that caused lysosome enlargement in C. elegans macrophage-like cells. Intriguingly, these compounds triggered cell death in the germ line independently of the canonical apoptosis pathway. In mammalian cells, ervachinines A-D induced lysosomal enlargement and damage, leading to leakage of cathepsin proteases, inhibition of autophagosome degradation and necrotic cell death. Further analysis revealed that this ervachinine-induced lysosome damage and lysosomal cell death depended on STAT3 signaling, but not RIP1 or RIP3 signaling. These findings suggest that lysosome-damaging compounds are promising reagents for dissecting signaling mechanisms underlying lysosome homeostasis and lysosome-related human disorders.
Alkaloids ; pharmacology ; Animals ; Caenorhabditis elegans ; cytology ; drug effects ; metabolism ; Cell Death ; drug effects ; Cell Survival ; drug effects ; HeLa Cells ; Humans ; Lysosomes ; drug effects ; pathology ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; drug effects

TRPML1 channel is a non-selective group-2 transient receptor potential (TRP) channel with Ca permeability. Located mainly in late endosome and lysosome of all mammalian cell types, TRPML1 is indispensable in the processes of endocytosis, membrane trafficking, and lysosome biogenesis. Mutations of TRPML1 cause a severe lysosomal storage disorder called mucolipidosis type IV (MLIV). In the present study, we determined the cryo-electron microscopy (cryo-EM) structures of Mus musculus TRPML1 (mTRPML1) in lipid nanodiscs and Amphipols. Two distinct states of mTRPML1 in Amphipols are added to the closed state, on which could represent two different confirmations upon activation and regulation. The polycystin-mucolipin domain (PMD) may sense the luminal/extracellular stimuli and undergo a "move upward" motion during endocytosis, thus triggering the overall conformational change in TRPML1. Based on the structural comparisons, we propose TRPML1 is regulated by pH, Ca, and phosphoinositides in a combined manner so as to accommodate the dynamic endocytosis process.
Animals ; Calcium ; metabolism ; Cryoelectron Microscopy ; Endocytosis ; Endosomes ; metabolism ; Gene Expression ; HEK293 Cells ; Humans ; Hydrogen-Ion Concentration ; Lysosomes ; metabolism ; Mice ; Models, Biological ; Mucolipidoses ; genetics ; metabolism ; pathology ; Nanostructures ; chemistry ; ultrastructure ; Phosphatidylinositols ; metabolism ; Transgenes ; Transient Receptor Potential Channels ; chemistry ; genetics ; metabolism

Fabry disease is an X-linked lysosomal storage disorder caused by a deficiency of the enzyme α-galactosidase A, resulting in the accumulation of glycosphingolipids within the lysosomes of various cell types. It has a wide spectrum of clinical phenotypes, and renal failure is a serious complication. Fabry disease is confirmed either by measurement of α-galactosidase A activity or by genetic testing for GLA mutations. Renal biopsy findings on light microscopy, specifically enlarged podocytes with foamy cytoplasm, and osmiophilic inclusion bodies in the cytoplasm in all types of renal cells on electron microscopy, are characteristic of this disease. The predominant differential diagnosis is iatrogenic phospholipidosis in association with certain drugs that can cause cellular injuries indistinguishable from Fabry disease. Here, we report the case of a 10-year-old boy with microscopic hematuria who underwent a renal biopsy that showed morphological findings consistent with Fabry disease, although the patient had neither a GLA mutation nor a history of drug consumption. Six years later, spontaneous regression of this renal pathology was observed in a second renal biopsy examination.
Biopsy* ; Child* ; Cytoplasm ; Diagnosis, Differential ; Fabry Disease* ; Genetic Testing ; Glycosphingolipids ; Hematuria* ; Humans ; Inclusion Bodies ; Lysosomes ; Male* ; Microscopy ; Microscopy, Electron ; Pathology ; Phenotype ; Podocytes ; Renal Insufficiency

Microglia play a pivotal role in clearance of Aβ by degrading them in lysosomes, countering amyloid plaque pathogenesis in Alzheimer's disease (AD). Recent evidence suggests that lysosomal dysfunction leads to insufficient elimination of toxic protein aggregates. We tested whether enhancing lysosomal function with transcription factor EB (TFEB), an essential regulator modulating lysosomal pathways, would promote Aβ clearance in microglia. Here we show that microglial expression of TFEB facilitates fibrillar Aβ (fAβ) degradation and reduces deposited amyloid plaques, which are further enhanced by deacetylation of TFEB. Using mass spectrometry analysis, we firstly confirmed acetylation as a previously unreported modification of TFEB and found that SIRT1 directly interacted with and deacetylated TFEB at lysine residue 116. Subsequently, SIRT1 overexpression enhanced lysosomal function and fAβ degradation by upregulating transcriptional levels of TFEB downstream targets, which could be inhibited when TFEB was knocked down. Furthermore, overexpression of deacetylated TFEB at K116R mutant in microglia accelerated intracellular fAβ degradation by stimulating lysosomal biogenesis and greatly reduced the deposited amyloid plaques in the brain slices of APP/PS1 transgenic mice. Our findings reveal that deacetylation of TFEB could regulate lysosomal biogenesis and fAβ degradation, making microglial activation of TFEB a possible strategy for attenuating amyloid plaque deposition in AD.
Alzheimer Disease ; metabolism ; pathology ; Amyloid beta-Peptides ; metabolism ; Amyloid beta-Protein Precursor ; genetics ; metabolism ; Animals ; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors ; chemistry ; genetics ; metabolism ; Brain ; metabolism ; Cells, Cultured ; Chloride Channels ; genetics ; metabolism ; Disease Models, Animal ; HEK293 Cells ; Humans ; Lysosomes ; genetics ; metabolism ; Mice ; Mice, Transgenic ; Microglia ; cytology ; metabolism ; Mutagenesis, Site-Directed ; Peptides ; analysis ; chemistry ; Protein Binding ; RNA Interference ; Sirtuin 1 ; antagonists & inhibitors ; genetics ; metabolism

Apoptosis ; Calcineurin ; metabolism ; Chymotrypsin ; metabolism ; Humans ; Lysosomes ; enzymology ; Mitochondria ; metabolism ; pathology ; Mitochondrial Dynamics ; Neuroblastoma ; metabolism ; pathology

OBJECTIVETo explore the clinical characteristics of Wolman disease and diagnostic methods using enzymatic and molecular analysis.

METHODLysosomal acid lipase activity was measured using 4-methylumbelliferyl oleate in the leukocytes of an infant suspected of Wolman disease and LIPA gene mutational analysis was performed by PCR and direct sequencing in the proband and his parents. After the diagnosis was confirmed, the clinical, biochemical, radiological and histopathological findings in this case of Wolman disease were retrospectively reviewed.

RESULTThe sixteen-day-old boy was failing to thrive with progressive vomiting, abdominal distention and hepatosplenomegaly. Abdominal X-ray revealed adrenal calcifications which were confirmed on abdominal CT scan. Xanthomatosis were observed on enlarged liver, spleen and lymph nodes during abdominal surgery. Liver and lymph node biopsy showed foamy histiocytes. The lysosomal acid lipase activity in leukocytes was 3.5 nmol/(mg·h) [control 35.5 - 105.8 nmol/(mg·h)]. Serum chitotriosidase activity was 315.8 nmol/(ml·h) [control 0 - 53 nmol/(ml·h)]. The patient was homozygote for a novel insert mutation allele c.318 ins T, p. Phe106fsX4 in exon 4 on LIPA gene. His both parents were carriers of the mutation.

CONCLUSIONThe clinical features of Wolman disease include early onset of vomiting, abdominal distention, growth failure, hepatosplenomegaly and bilateral adrenal calcification after birth. A plain abdominal X-ray film should be taken to check for the typical pattern of adrenal calcification in suspected cases of Wolman disease. The enzymatic and molecular analyses of lysosomal acid lipase can confirm the diagnosis of Wolman disease.

Adrenal Gland Diseases ; etiology ; pathology ; Exons ; Humans ; Infant, Newborn ; Leukocytes ; enzymology ; Lipase ; blood ; genetics ; Liver ; pathology ; Lysosomes ; enzymology ; genetics ; Male ; Mutation ; Polymerase Chain Reaction ; Splenomegaly ; pathology ; Sterol Esterase ; genetics ; Tomography, X-Ray Computed ; Wolman Disease ; diagnosis ; enzymology ; genetics ; pathology

OBJECTIVE: To study the expression of cathepsin-B and -D in different time point after traumatic brain injury. METHODS: Traumatic brain injury (TBI) model was established on rats, cathepsin-B and cathepsin-D immunofluorescence staining and confocal microscope analysis were performed. Positive cells were counted by confocal microscope and image analysis techniques were used to determine the morphological changes in each group. RESULTS: Immunofluorescence staining results showed that cathepsin-B was activated 1 hour after TBI while cathepsin-D was not activated until 12hour after TBI. Both of them got to their peak during 4 to 8days, and kept a high level of activating 32days after TBI. Cathepsin-B and -D positive cells did not merge with caspase-3 positive cells until 6 h after TBI. CONCLUSION Cathepsin-B and -D could be the diagnostic markers of TBI and can estimating time course of lateral TBI. They blocked caspase-3 activation at the beginning period after TBI and started to promote cell death with caspase-3 6 h after TBI.
Animals ; Brain/pathology* ; Brain Injuries/pathology* ; Caspase 3/metabolism* ; Cathepsin B/metabolism* ; Cathepsin D/metabolism* ; Disease Models, Animal ; Forensic Pathology ; Hippocampus/pathology* ; Immunohistochemistry ; Lysosomes ; Male ; Neurons/metabolism* ; Rats ; Rats, Sprague-Dawley ; Time Factors