Primary coenzyme Q10 (CoQ) deficiency includes a heterogeneous group of mitochondrial diseases characterized by low mitochondrial levels of CoQ due to decreased endogenous biosynthesis rate. These ...diseases respond to CoQ treatment mainly at the early stages of the disease. The advances in the next generation sequencing (NGS) as whole-exome sequencing (WES) and whole-genome sequencing (WGS) have increased the discoveries of mutations in either gene already described to participate in CoQ biosynthesis or new genes also involved in this pathway. However, these technologies usually provide many mutations in genes whose pathogenic effect must be validated. To functionally validate the impact of gene variations in the disease’s onset and progression, different cell models are commonly used. We review here the use of yeast strains for functional complementation of human genes, dermal skin fibroblasts from patients as an excellent tool to demonstrate the biochemical and genetic mechanisms of these diseases and the development of human-induced pluripotent stem cells (hiPSCs) and iPSC-derived organoids for the study of the pathogenesis and treatment approaches.
Originally identified as a key component of the mitochondrial respiratory chain, Coenzyme Q (CoQ or CoQ
for human tissues) has recently been revealed to be essential for many different redox ...processes, not only in the mitochondria, but elsewhere within other cellular membrane types. Cells rely on endogenous CoQ biosynthesis, and defects in this still-not-completely understood pathway result in primary CoQ deficiencies, a group of conditions biochemically characterised by decreased tissue CoQ levels, which in turn are linked to functional defects. Secondary CoQ deficiencies may result from a wide variety of cellular dysfunctions not directly linked to primary synthesis. In this article, we review the current knowledge on CoQ biosynthesis, the defects leading to diminished CoQ
levels in human tissues and their associated clinical manifestations.
Abstract The protein encoded by COQ7 is required for CoQ 10 synthesis in humans, hydroxylating 3‐demethoxyubiquinol (DMQ 10 ) in the second to last steps of the pathway. COQ7 mutations lead to a ...primary CoQ 10 deficiency syndrome associated with a pleiotropic neurological disorder. This study shows the clinical, physiological, and molecular characterization of four new cases of CoQ 10 primary deficiency caused by five mutations in COQ7 , three of which have not yet been described, inducing mitochondrial dysfunction in all patients. However, the specific combination of the identified variants in each patient generated precise pathophysiological and molecular alterations in fibroblasts, which would explain the differential in vitro response to supplementation therapy. Our results suggest that COQ7 dysfunction could be caused by specific structural changes that affect the interaction with COQ9 required for the DMQ 10 presentation to COQ7, the substrate access to the active site, and the maintenance of the active site structure. Remarkably, patients' fibroblasts share transcriptional remodeling, supporting a modification of energy metabolism towards glycolysis, which could be an adaptive mechanism against CoQ 10 deficiency. However, transcriptional analysis of mitochondria‐associated pathways showed distinct and dramatic differences between patient fibroblasts, which correlated with the extent of pathophysiological and neurological alterations observed in the probands. Overall, this study suggests that the combination of precise genetic diagnostics and the availability of new structural models of human proteins could help explain the origin of phenotypic pleiotropy observed in some genetic diseases and the different responses to available therapies.
HCV is associated with an increased risk of cardiovascular events (CV). Whether HCV clearance by direct-acting antivirals (DAA) reduces incident CV disease is poorly understood. We investigate ...whether HCV eradication reduces CV events.
In a prospective multicentre study, 2204 HCV patients (F0–F2:29.5%, F3–F4: 70.5%) were enrolled. Males were 48%, median age was 68 (59–74) years and BMI 25.9 (23.1–28); 24.7% were smokers, 18% had diabetes, 13.2% had cholesterol levels >200 mg/dl and 9.1% took statins, 44% had hypertension. During an overall median follow-up of 28 (24–39) months, incident CV events, such as ischemic heart disease (IHD) and ischemic cerebral stroke (ICS), were recorded. An overall of 2204 patients were evaluated as control group and 1668 patients after HCV elimination were followed as a case group. Factors associated with CV events were evaluated by uni- and multi-variate analyses.
Incident CV rates per 100 patient years in pre-treatment and untreated controls and treated cases were 1.12, 1.14 and 0.44 (p = 0.0001 vs. controls), respectively, and a decreased of relative risk (RR = 0.379; p = 0.0002) was observed. CV risk was 2.0–3.5 times lower then in controls (HR 3.671; 95%C.I.:1.871–7.201; p < 0.001). The calculated number of patients to be treated to get a benefit in a patient was 55.26. The annual incidence reduction of CV events was 0.68%. HCV clearance was independently associated with CV events reduction (OR, 4.716; 95% C.I.:1.832–12.138; p = 0.001).
HCV clearance by DAA reduces CV events (IHD and ICS) with both clinical and socio-economic benefits.
•HCV clearance by direct-acting antivirals (DAA) significantly reduces the annual incidence of cardio vascular events by 0.68%.•Incident cardiovascular events (CV) rates for 100 patient years in controls was 1.14 and in cases 0.44.•The CV risk after HCV clearance was reduced by 2.0–3.5 folds.•The calculated number of patients to be treated to get a benefit in a patient was 55.26.•HCV clearance was independently associated with CV events reduction.
Batten disease, one of the most devastating types of neurodegenerative lysosomal storage disorders, is caused by mutations in CLN3. Here, we show that CLN3 is a vesicular trafficking hub connecting ...the Golgi and lysosome compartments. Proteomic analysis reveals that CLN3 interacts with several endo-lysosomal trafficking proteins, including the cation-independent mannose 6 phosphate receptor (CI-M6PR), which coordinates the targeting of lysosomal enzymes to lysosomes. CLN3 depletion results in mis-trafficking of CI-M6PR, mis-sorting of lysosomal enzymes, and defective autophagic lysosomal reformation. Conversely, CLN3 overexpression promotes the formation of multiple lysosomal tubules, which are autophagy and CI-M6PR-dependent, generating newly formed proto-lysosomes. Together, our findings reveal that CLN3 functions as a link between the M6P-dependent trafficking of lysosomal enzymes and lysosomal reformation pathway, explaining the global impairment of lysosomal function in Batten disease.
Autophagy is a cytosolic quality control process that recognizes substrates through receptor‐mediated mechanisms. Procollagens, the most abundant gene products in Metazoa, are synthesized in the ...endoplasmic reticulum (ER), and a fraction that fails to attain the native structure is cleared by autophagy. However, how autophagy selectively recognizes misfolded procollagens in the ER lumen is still unknown. We performed siRNA interference, CRISPR‐Cas9 or knockout‐mediated gene deletion of candidate autophagy and ER proteins in collagen producing cells. We found that the ER‐resident lectin chaperone Calnexin (CANX) and the ER‐phagy receptor FAM134B are required for autophagy‐mediated quality control of endogenous procollagens. Mechanistically, CANX acts as co‐receptor that recognizes ER luminal misfolded procollagens and interacts with the ER‐phagy receptor FAM134B. In turn, FAM134B binds the autophagosome membrane‐associated protein LC3 and delivers a portion of ER containing both CANX and procollagen to the lysosome for degradation. Thus, a crosstalk between the ER quality control machinery and the autophagy pathway selectively disposes of proteasome‐resistant misfolded clients from the ER.
Synopsis
Unfolded procollagen in the endoplasmic reticulum (ER) is an ER‐associated degradation‐resistant substrate that has to be cleared by autophagy. The ER chaperone Calnexin and the ER‐phagy receptor FAM134B recognize misfolded procollagen and mediate its LC3‐dependent delivery to the lysosome for autophagic degradation.
A candidate deletion screen shows that calnexin and FAM134B are required for ER quality control of endogenous procollagens
Calnexin acts as co‐receptor recognizing misfolded procollagen within the ER lumen
FAM134B binds misfolded procollagen through Calnexin and links it to LC3 on autophagosomal membranes
Calnexin and the ER‐phagy receptor FAM134B recognize misfolded procollagen in the ER and mediate its LC3‐dependent delivery to the lysosome for autophagic degradation.
Abstract
Background
Besides major clinical/biochemical features, neutropenia and inflammatory bowel disease (IBD) constitute common complications of Glycogen storage disease type Ib (GSD Ib). ...However, their management is still challenging. Although previous reports have shown benefit of empagliflozin administration on neutropenia, no follow-up data on bowel (macro/microscopic) morphology are available. We herein present for the first time longitudinal assessment of bowel morphology in a GSD Ib child suffering from Crohn disease-like enterocolitis treated with empagliflozin.
Case presentation
A 14-year-old boy with GSD Ib and severe IBD was (off-label) treated with empagliflozin (20 mg/day) after informed oral and written consent was obtained from the patient’s parents. No adverse events were noted. Clinical symptoms and stool frequency improved within the first week of treatment. Pediatric Crohn disease activity index (PCDAI) normalised within the first month of treatment. Abdomen magnetic resonance imaging (MRI) performed 3 months after treatment initiation showed dramatic decrease in disease activity and length. Similar findings were reported on histology at 5.5 months. At 7.5 months hemoglobin levels normalised and fecal calprotectin almost normalised. Improved neutrophil count, metabolic control and quality of life were also noted. G-CSF dose was decreased by 33% and the patient was partly weaned from tube feeding.
Conclusions
This is the first report presenting extensive gastrointestinal morphology follow-up in a GSD Ib patient receiving empagliflozin. The present case suggests that empagliflozin can be safe and effective in inducing IBD remission in GSD Ib patients and can even postpone surgery. Future studies are required to confirm its effect over time and assess its benefit in various disease stages. The development of an international collaborating networks for systematic data collection is worthy.
Aim
To assess the effect of hepatitis C virus (HCV) eradication on type 2 diabetes mellitus (T2DM). incidence.
Methods
A prospective multicentre case–control study was performed, which included 2426 ...patients with HCV, 42% of whom had liver fibrosis stage F0‐F2 and 58% of whom had liver fibrosis stage F3‐F4. The study population consisted of a control group including 1099 untreated patients and 1327 cases treated with direct‐acting antivirals (DAAs). T2DM incidence was assessed during a median (interquartile range) follow‐up period of 30 (28–42) months. Risk factors for T2DM were assessed using a Cox regression model (relative risk RR, hazard ratio HR, Kaplan–Meier analysis). Insulin sensitivity was evaluated by homeostatic model assessment (HOMA) and changes by repeated‐measures ANOVA. Factors independently associated with T2DM were assessed by multivariate analysis.
Results
The absolute incidence of T2DM for controls and cases was 28 and 7/1000 person‐years, respectively (P = 0.001). In cases compared to controls, HCV clearance reduced the RR and HR of T2DM by 81% and 75% to 93%, respectively (P = 0.001). It was calculated that, for every 15 patients who obtained HCV clearance, one case of T2DM was saved. HCV clearance was associated with significant reductions in HOMA‐insulin resistance and HOMA‐β‐cell function and an increase in HOMA‐insulin sensitivity, as assessed in 384 patients before and after HCV clearance. At multivariate analysis, HCV clearance emerged as independently associated with a reduced T2DM risk.
Conclusion
The results showed that HCV clearance by DAA treatment reduces T2DM incidence probably by restoring the HCV‐induced alteration of glucose homeostasis mechanisms.
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