Autophagic vacuolar myopathy in twin girls

Cardioprotective role of oleanolic acid in patients with type 2 diabetes mellitus

Background

Patients with type 2 diabetes mellitus (T2DM) experience a decline in cardiac function, resulting in poor prognosis. Therefore, restoration of cardiac function and improvement of myocardial fibrosis is an important treatment goal for patients with T2DM.

Material and methods

The chemical structure of oleanolic acid(OA) was downloaded from PubChem and uploaded to PharmMapper. GeneCards and OMIM databases were searched for genes related to OA and disease and plotted into a Venn diagram. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed using R software. Then, a mouse model of diabetes mellitus was established, and ELISA, echocardiographic analysis of cardiac function, TUNEL assay, and reactive oxygen species assay were performed.

Results

Network pharmacology analysis identified the related targets and potential molecular mechanisms underlying the effects of OA in T2DM. ELISA, echocardiographic analysis of cardiac function, and TUNEL assay results showed that OA inhibits apoptosis and improves apoptotic indexes in mice with T2DM-induced myocardial injury.

Conclusion

The results demonstrate the myocardial protective effect of OA in this mouse model.

Autophagy Defects in Skeletal Myopathies

Autophagy is an evolutionarily conserved catabolic process that targets different types of cytoplasmic cargo (such as bulk cytoplasm, damaged cellular organelles, and misfolded protein aggregates) for lysosomal degradation. Autophagy is activated in response to biological stress and also plays a critical role in the maintenance of normal cellular homeostasis; the latter function is particularly important for the integrity of postmitotic, metabolically active tissues, such as skeletal muscle. Through impairment of muscle homeostasis, autophagy dysfunction contributes to the pathogenesis of many different skeletal myopathies; the observed autophagy defects differ from disease to disease but have been shown to involve all steps of the autophagic cascade (from induction to lysosomal cargo degradation) and to impair both bulk and selective autophagy. To highlight the molecular and cellular mechanisms that are shared among different myopathies with deficient autophagy, these disorders are discussed based on the nature of the underlying autophagic defect rather than etiology or clinical presentation.

Selective and sensitive visualization of endogenous nitric oxide in living cells and animals by a Si-rhodamine deoxylactam-based near-infrared fluorescent probe

A Si-rhodamine deoxylactam-based near-infrared fluorescent probe has been successfully developed for the imaging of endogenous NO in living cells and mouse models.

Nitric oxide (NO) is a fundamental signaling molecule that regulates virtually every critical cellular function, and it is also a potent mediator of cellular damage in a wide range of conditions mainly via its secondary metabolite peroxynitrite (ONOO^–). In this work, we present an o-phenylenediamine (OPD)-locked Si-rhodamine deoxylactam, i.e.deOxy-DALSiR, as a near-infrared fluorescent probe for the selective and sensitive detection of NO in living cells and bodies. Not only could the probe overcome the limitations suffered by widely used and commercialized OPD-type fluorescent NO probes, such as the possible interferences by dehydroascorbic acid/ascorbic acid/methylglyoxal (DHA/AA/MGO), pH-sensitive fluorescence output, and short excitation and emission wavelengths, but it can also avoid serious interference from cysteine (Cys) found in the rhodamine lactam-based fluorescent NO probes developed later. What’s more, the probe is fairly sensitive for NO, as evidenced by its rapid fluorescence response rate (within seconds), huge fluorescence off–on ratio (6300-fold), and ultra-low detection limit (0.12 nM). Its effectiveness and practicability have been demonstrated by the successful imaging of endogenous NO in RAW 264.7 macrophages, pancreatic β-cells, and endothelial EA.hy926 cells, as well as in inflamed and diabetic mouse models.

Engineering a nanolab for the determination of lysosomal nitric oxide by the rational design of a pH-activatable fluorescent probe

A pH-activatable fluorescent probe, Rhod-H-NO, was designed and synthesized for the determination of lysosomal NO in living cells and in vivo.

Nitric oxide (NO) is often involved in many different physiological processes including the regulation of lysosomal functions. However, it remains a great challenge to explore the variations of NO levels in lysosomes, limiting the understanding behind its biological functions in cellular signaling pathways and various diseases. Herein, a pH-activatable fluorescent probe, Rhod-H-NO, was designed and synthesized for the determination of lysosomal NO, in which the activation response model is beneficial towards getting accurate biological information. To ensure that Rhod-H-NO can accumulate effectively and exist stably in lysosomes without interference and degradation from other active species, Rhod-H-NO was engineered into the nanopores of mesoporous silica nanoparticles (MSNs) with β-cyclodextrin (β-CD) as the gatekeeper to obtain a nanolab. The nanolab was successfully applied to detect lysosomal NO in living cells and in vivo with high time and spatial resolution. This nanolab could serve as an excellent molecular tool to exploit and elucidate the function of NO at sub-cellular levels.

X-linked myopathy with excessive autophagy: a failure of self-eating

Autophagic vacuolar myopathies (AVMs) are a group of disorders united by shared histopathological features on muscle biopsy that include the aberrant accumulation of autophagic vacuoles. The classic conditions that compose the AVMs include Pompe Disease, Danon Disease and X-linked myopathy with excessive autophagy (XMEA). Other disorders, including acquired myopathies like chloroquine toxicity, also have features of an autophagic myopathy. This review is focused on XMEA, a myopathy with onset of slowly progressive proximal weakness and elevated serum creatine kinase (2× to 20× normal) typically in the first decade of life. However, both late-adult onset and severe, sometimes lethal, neonatal cases also occur. Skeletal muscle pathology is characterized by numerous cytoplasmic autophagic vacuoles, complex muscle fiber splitting with internalization of capillaries, and complement C5b-9 deposition within vacuoles and along the sarcolemma. The autophagic vacuoles have sarcolemmal features. Mutations in the VMA21 gene at Xq28 cause XMEA by reducing the activity of lysosomal hydrolases. The VMA21 protein regulates the assembly of the V-ATPase required to acidify the lysosome. Increased lysosomal pH and poor degradation of cellular debris may secondarily induce autophagy, the net effect being accumulation of autophagolysosomes. The relationship of XMEA to other lysosomal disorders of muscle and potential therapeutic interventions for XMEA are discussed.

A lysosome-targetable and two-photon fluorescent probe for monitoring endogenous and exogenous nitric oxide in living cells

A lysosome-specific and two-photon fluorescent probe, Lyso-NINO, demonstrates high selectivity and sensitivity toward NO, lower cytotoxicity, and perfect lysosomal localization. With the aid of Lyso-NINO, the first capture of NO within lysosomes of macrophage cells has been achieved using both two-photon fluorescence microscopy and flow cytometry.

An autophagic vacuolar myopathy-like disorder presenting as nonimmune hydrops in a female fetus

A 37-year-old woman presented for routine obstetrical care at 15 weeks' gestational age and the fetus was found to have hydrops fetalis. Following elective termination of the pregnancy at 18 weeks' gestational age, pathologic examination of the female conceptus revealed findings suggestive of a lysosomal storage disease within the liver and cardiac muscle. Enzyme assays for beta-galactosidase, neuraminidase, alpha-l-iduronidase, beta-glucuronidase, beta-glucosidase, Morquio disease type A enzyme, beta-fucosidase, alpha-mannosidase, and beta-mannosidase were all normal, ruling out many of the common storage diseases. Electron microscopy identified vacuoles within hepatocytes, Kupffer cells, and cardiac myocytes resembling the autophagic vacuoles characteristic of a group of diseases known as the autophagic vacuolar myopathies (AVMs). Because these diseases are exceptionally rare in females, and because such autophagic vacuoles have never before been described in liver, we propose a novel entity of "AVM-like lysosomal storage disease" presenting as nonimmune hydrops in a female fetus.

Danon disease as a cause of autophagic vacuolar myopathy

Danon disease, an extremely rare X-linked dominant disorder, is characterized clinically by hypertrophic cardiomyopathy (HCM), skeletal myopathy, and variable degree of mental retardation with autophagic vacuoles in skeletal and cardiac muscle. Reportedly, Danon disease is caused by a primary deficiency of a major lysosomal membrane glycoprotein, LAMP2 (lysosome-associated membrane protein 2). Here we review the clinical features, molecular genetics, related animal model, and differential diagnosis of Danon disease.