The N-terminal shuttle domain of Erv1 determines the affinity for Mia40 and mediates electron transfer to the catalytic Erv1 core in yeast mitochondria

Erv1 and Mia40 constitute the two important components of the disulfide relay system that mediates oxidative protein folding in the mitochondrial intermembrane space. Mia40 is the import receptor that recognizes the substrates introducing disulfide bonds while it is reduced. A key function of Erv1 is to recycle Mia40 to its active oxidative state. Our aims here were to dissect the domain of Erv1 that mediates the protein–protein interaction with Mia40 and to investigate the interactions between the shuttle domain of Erv1 and its catalytic core and their relevance for the interaction with Mia40. We purified these domains separately as well as cysteine mutants in the shuttle and the active core domains. The noncovalent interaction of Mia40 with Erv1 was measured by isothermal titration calorimetry, whereas their covalent mixed disulfide intermediate was analyzed in reconstitution experiments in vitro and in organello. We established that the N-terminal shuttle domain of Erv1 is necessary and sufficient for interaction to occur. Furthermore, we provide direct evidence for the intramolecular electron transfer from the shuttle cysteine pair of Erv1 to the core domain. Finally, we reconstituted the system by adding in trans the N- and C- terminal domains of Erv1 together with its substrate Mia40

Mitophagy and the therapeutic clearance of damaged mitochondria for neuroprotection

Mitochondria are the foremost producers of the cellular energy currency ATP. They are also a significant source of reactive oxygen species and an important buffer of intracellular calcium. Mitochondrial retrograde signals regulate energy homeostasis and pro-survival elements whereas anterograde stimuli can trigger programmed cell death. Maintenance of a healthy, functional mitochondria network is therefore essential, and several mechanisms of mitochondrial quality control have been described. Mitochondrial dysfunction is linked to several neurodegenerative conditions including Parkinson, and Huntingdon diseases as well as Amyotrophic lateral sclerosis. Understanding the mechanisms governing mitochondrial quality control may reveal novel strategies for pharmacological intervention and disease therapy

Impact of pre-transplant time on dialysis on survival in patients with lupus nephritis

Lupus nephritis (LN) is an important cause of morbidity and mortality in patients with systemic lupus erythematosus (SLE) often leading to end-stage renal failure (ESRF) and necessitating renal transplantation (rTp). Optimal timing of rTp in SLE patients with ESRF is uncertain and could potentially affect survival. We investigated the time spent on dialysis before rTp and survival following rTp in a cohort of SLE patients. Retrospective analysis of all adult SLE patients receiving rTp over a 40-year period (1975–2015) in two tertiary UK centres. Cox proportional hazard regression and receiver operator curves (ROC) were used to determine the risk associated with time on dialysis before rTp and other potential predictors. Forty patients (age 35 ± 11 years, 34 female, 15 Caucasian, 15 Afro–Caribbean and 10 South Asian) underwent rTp. During a median follow-up of 104 months (IQR 80,145), eight (20%) patients died and the 5-year survival was 95%. Univariate analysis identified time on dialysis prior to rTp as the only potentially modifiable risk predictor of survival with a hazard ratio of 1.013 for each additional month spent on dialysis (95% CI = 1.001–1.026, p = 0.03). ROC curves demonstrated that > 24 months on dialysis had an adverse effect with sensitivity of 0.875 and specificity 0.500 for death. No other modifiable predictors were significantly associated with mortality, indicating that time on dialysis had an independent effect. Increased time on dialysis pre-transplantation is an independent modifiable risk factor of mortality in this cohort of patients with lupus nephritis

Role of tryptophan residues of Erv1: Trp95 and Trp183 are important for its folding and oxidase function

Erv1 is an FAD-dependent sulphydryl oxidase of the ERV/ALR sub-family, and an essential component of the mitochondrial import and assembly pathway. Erv1 contains six tryptophan residues, which are all located in the highly conserved C-terminal FAD-binding domain. Though important structural roles were predicted for the invariable Trp95, no experimental study has been reported. In this study, we investigated the structural and functional roles of individual Trp residues of Erv1. Six single Trp-to-Phe yeast mutant strains were generated and their effects on cell viability were tested at various temperatures. Then, the mutants were purified from E. coli. Their effects on folding, FAD-binding, and Erv1 activity were characterised. Our results showed that Erv1W95F has the strongest effect on the stability and function of Erv1, and followed by Erv1W183F. Erv1W95F results in a decrease of the Tm of Erv1 by 23°C, a significant loss of the oxidase activity, and thus causing cell growth defects at both 30°C and 37°C. Erv1W183F induces changes in the oligomerisation state of Erv1, along with a pronounced effect on the stability of Erv1 and its function at 37°C, whilst the other mutants had no clear effect on the function of Erv1 including the highly conserved Trp157 mutant. Finally, computational analysis indicates that Trp95 plays a key role in stabilising the isoalloxazine ring to interact with Cys133. Taken together, this study provided important insights into the molecular mechanism of how sulfhydryl oxidases use FAD in catalyzing disulfide bond formation

Pauci-Immune Vasculitides with Kidney Involvement

The clinical entity of pauci-immune vasculitis encompasses a group of diseases that may involve any organ system of the body and may be fatal if left untreated. This chapter will review these diseases, with a special interest in the clinical setting of kidney involvement. Small vessel vasculitides associated with the presence of antineutrophil cytoplasmic autoantibodies in the circulation will be the main part, since the vast majority of patients with histopathological proof of pauci-immune vasculitis are positive for these antibodies. Pauci-immune glomerulonephritis often manifests with rapidly deteriorating kidney function, while it may be accompanied by systemic necrotizing small vessel vasculitis such as microscopic polyangiitis, granulomatosis with polyangiitis, or eosinophilic granulomatosis with polyangiitis. Importantly, antineutrophil cytoplasmic autoantibody specificity has been shown to be associated with distinct clinical syndromes and different prognostic profiles among patients with pauci-immune vasculitis allowing easier recognition of the disease and long-term prognosis. Each of the clinical phenotypes will be described thoroughly with respect to the criteria required for establishment of diagnosis, the specific characteristics of renal and extrarenal histopathology, the clinical picture, the therapeutic management, and prognosis in short and long terms

Immune Complex Small-Vessel Vasculitis with Kidney Involvement

The term immune complex small-vessel vasculitis encompasses anti-glomerular basement membrane disease, cryoglobulinemic vasculitis, IgA vasculitis and hypocomplementemic urticarial vasculitis. These disorders affect predominantly small vessels, and renal involvement is frequent. In this chapter, we shall discuss thoroughly anti-GBM disease, cryoglobulinemic and IgA vasculitis with respect to the criteria required for the establishment of diagnosis, the specific characteristics of renal histopathology, the clinical picture, prognosis, and therapeutic management

Two cases of lymphoepithelial cyst of the pancreas

A 35-year-old man was found to have a cystic mass in the pancreatic body on a routine health examination ; high serum CA19-9 was also detected. The enucleated cyst was diagnosed as a lymphoepithelial cyst (LEC). A 74-year-old man found to have a cystic mass in the pancreatic head by computer tomography as well as high serum CA19-9 was suspected of a cystic neoplasm of the pancreas (IPMN), and pylorus-preserving pancreaticoduodenectomy (PPPD) was performed. Pathologically, the cyst was found to be LEC. It is often difficult to diagnose pancreatic cyst as LEC preoperatively. Care should be taken not to do over-surgery for benign disease LEC

Novel insights into the aetiology of granulomatosis with polyangiitis—a case–control study using the Clinical Practice Research Datalink

Objectives We aimed to provide insights into the aetiology of granulomatosis with polyangiitis (GPA), by conducting a large case–control study using a general population-based, prospectively collected database of healthcare records. Methods We compared all incident cases of GPA in the Clinical Practice Research Datalink 1990–2014, with up to 10 age-, sex- and general practice-matched controls. We identified potential risk factors, recorded numbers of cases and controls exposed to each, and calculated odds ratios (ORs) using conditional logistic regression. Our main analysis excluded data recorded during 1 year before diagnosis, to prevent early symptoms being mistaken for risk factors. Results We identified 757 people with GPA and matched 7546 controls. People with GPA were five times more likely to have a previous diagnosis of bronchiectasis (OR = 5.1, 95% CI: 2.7, 9.4; P 5 years prior to diagnosis. People with GPA were two to three times more likely than controls to have previous diagnoses of autoimmune diseases or chronic renal impairment, and these effects also remained stable >5 years prior to diagnosis. People with GPA were more likely to have a diagnosis of pulmonary fibrosis (OR = 5.7, 95% CI: 1.7, 19.5; P = 0.01) and sinus infections (OR = 2.7, 95% CI: 1.8, 4.2; P < 0.0001) recorded in the 3 years before diagnosis, but not before this. We also found former smoking, some medications and higher socio-economic status significantly, but less strongly, associated. Conclusion We found novel long-term associations between GPA and pre-existing bronchiectasis and autoimmune diseases

Editorial: Pathogenesis and management of glomerular diseases

Glomerular diseases are considered to be the result of inherited or acquired disorders and may manifest in a variety of clinical syndromes, including numerous pictures in terms of severity. A significant number of patients have no symptoms while others discover urinary abnormalities in routine screenings or they may experience low grade symptoms, such as macroscopic hematuria and edema in the lower extremities. Occasional patients present with rapidly progressive glomerulonephritis, a serious condition which may end up in advanced or end-stage kidney disease if remain untreated. Renal histopathology evaluation in combination with the characteristics of the clinical syndrome remains the cornerstone for accurate diagnosis and evidence-based treatment. During the past decade substantial progress has been made in this field, especially regarding the etiology and pathogenesis of these diseases. Recent knowledge has been added, including molecular mechanisms, genetic associations and immunologically-mediated forms of glomerulonephritis, underlining the autoimmune basis associated with genetic risk factors and environmental stimulus leading to immune-mediated injury of the glomeruli