Characterisation of rejection episodes in an incident population of kidney transplant recipients

Kidney transplantation (Tx) is the therapy of choice for end-stage renal disease. It has been proven that the survival within transplanted patients, compared with dialysis patients, is greater. However, it is known that several factors can influence the graft outcome. One of them is the acute rejection, resulting from the innate and adaptive immune responses to foreign donor antigens. However, no study has been conducted to identify what are this factors in our centre yet. In this study, we aim to update the database of the Lausanne/CHUV kidney transplant recipients cohort in order to characterize this population. We intend to identify the determinants associated with graft rejection and graft outcome at 1-year post transplantation. Clinical data are provided from the CHUV prospective databases from the day of Tx to one year post Tx. We first performed a general analysis of all confounding factors that we considered relevant based on recipients’ graft function at one year after Tx. We studied then associations between immunological and clinical factor with acute graft rejection. We finally compared acute cellular rejection (ACR) to acute antibody mediated rejection (AMR). After one year, the rate of acute rejection was 15.9% (47.5% ACR and 25% AMR). Main found predictors tended to be related rather with acute AMR and reflected presensitization (prior transplantation, positive last PRA values and pre-existing DSA). Acute rejection was associated with decreased renal function (by around 14 ml/min of GFR in the first year)

Interleukin-35-Producing CD8α(+) Dendritic Cells Acquire a Tolerogenic State and Regulate T Cell Function.

Dendritic cells (DCs) play a central role in shaping immunogenic as well as tolerogenic adaptive immune responses and thereby dictate the outcome of adaptive immunity. Here, we report the generation of a CD8α(+) DC line constitutively secreting the tolerogenic cytokine interleukin (IL)-35. IL-35 secretion led to impaired CD4(+) and CD8(+) T lymphocyte proliferation and interfered with their function in vitro and also in vivo. IL-35 was furthermore found to induce a tolerogenic phenotype on CD8α(+) DCs, characterized by the upregulation of CD11b, downregulation of MHC class II, a reduced costimulatory potential as well as production of the immunomodulatory molecule IL-10. Vaccination of mice with IL-35-expressing DCs promoted tumor growth and reduced the severity of autoimmune encephalitis not only in a preventive but also after induction of encephalitogenic T cells. The reduction in experimental autoimmune encephalitis severity was significantly more pronounced when antigen-pulsed IL-35(+) DCs were used. These findings suggest a new, indirect effector mechanism by which IL-35-responding antigen-presenting cells contribute to immune tolerance. Furthermore, IL-35-transfected DCs may be a promising approach for immunotherapy in the context of autoimmune diseases

NsrR: a key regulator circumventing Salmonella enterica serovar Typhimurium oxidative and nitrosative stress in vitro and in IFN-γ-stimulated J774.2 macrophages

Over the past decade, the flavohaemoglobin Hmp has emerged as the most significant nitric oxide (NO)-detoxifying protein in many diverse micro-organisms, particularly pathogenic bacteria. Its expression in enterobacteria is dramatically increased on exposure to NO and other agents of nitrosative stress as a result of transcriptional regulation of hmp gene expression, mediated by (at least) four regulators. One such regulator, NsrR, has recently been shown to be responsible for repression of hmp transcription in the absence of NO in Escherichia coli and Salmonella, but the roles of other members of this regulon in Salmonella, particularly in surviving nitrosative stresses in vitro and in vivo, have not been elucidated. This paper demonstrates that an nsrR mutant of Salmonella enterica Serovar Typhimurium expresses high levels of Hmp both aerobically and anaerobically, exceeding those that can be elicited in vitro by supplementing media with S-nitrosoglutathione (GSNO). Elevated transcription of ytfE, ygbA, hcp and hcp is also observed, but no evidence was obtained for tehAB upregulation. The hyper-resistance to GSNO of an nsrR mutant is attributable solely to Hmp, since an nsrR hmp double mutant has a wild-type phenotype. However, overexpression of NsrR-regulated genes other than hmp confers some resistance of respiratory oxygen consumption to NO. The ability to enhance, by mutating NsrR, Hmp levels without recourse to exposure to nitrosative stress was used to test the hypothesis that control of Hmp levels is required to avoid oxidative stress, Hmp being a potent generator of superoxide. Within IFN-γ-stimulated J774.2 macrophages, in which high levels of nitrite accumulated (indicative of NO production) an hmp mutant was severely compromised in survival. Surprisingly, under these conditions, an nsrR mutant (as well as an nsrR hmp double mutant) was also disadvantaged relative to the wild-type bacteria, attributable to the combined oxidative effect of the macrophage oxidative burst and Hmp-generated superoxide. This explanation is supported by the sensitivity in vitro of an nsrR mutant to superoxide and peroxide. Fur has recently been confirmed as a weak repressor of hmp transcription, and a fur mutant was also compromised for survival within macrophages even in the absence of elevated NO levels in non-stimulated macrophages. The results indicate the critical role of Hmp in protection of Salmonella from nitrosative stress within and outside macrophages, but also the key role of transcriptional regulation in tuning Hmp levels to prevent exacerbation of the oxidative stress encountered in macrophages

Establishment and Characterization of a Functionally Competent Type 2 Conventional Dendritic Cell Line.

Dendritic cells (DCs) are the most potent antigen presenting cells and possess an incomparable ability to activate and instruct T cells, which makes them one of the cornerstones in the regulation of the cross-talk between innate and adaptive immunity. Therefore, a deep understanding of DC biology lays the foundations to describe and to harness the mechanisms that regulate the development of the adaptive response, with clear implications in a vast array of fields such as the study of autoimmune diseases and the development of new vaccines. However, the great difficulty to obtain large quantities of viable non-activated DCs for experimentation have considerably hindered the progress of DC research. Several strategies have been proposed to overcome these limitations by promoting an increase of DC abundance in vivo, by inducing DC development from DC progenitors in vitro and by generating stable DC lines. In the past years, we have described a method to derive immortalized stable DC lines, named MutuDCs, from the spleens of Mushi1 mice, a transgenic mouse strain that express the simian virus 40 Large T-oncogene in the DCs. The comparison of these DC lines with the vast variety of DC subsets described in vivo has shown that all the MutuDC lines that we have generated so far have phenotypic and functional features of type 1 conventional DCs (cDC1s). With the purpose of deriving DC lines with characteristics of type 2 conventional DCs (cDC2s), we bred a new Batf3 <sup>-/-</sup> Mushi1 murine line in which the development of the cDC1 subset is severely defective. The new MutuDC line that we generated from Batf3 <sup>-/-</sup> Mushi1 mice was phenotypically and functionally characterized in this work. Our results demonstrated that all the tested characteristics of this new cell line, including the expression of subset-determining transcription factors, the profile of cytokine production and the ability to present antigens, are comparable with the features of splenic CD4 <sup>-</sup> cDC2s. Therefore, we concluded that our new cell line, that we named CD4 <sup>-</sup> MutuDC2 line, represents a valuable model for the CD4 <sup>-</sup> cDC2 subset

Mutations in SPG11, encoding spatacsin, are a major cause of spastic paraplegia with thin corpus callosum.

Autosomal recessive hereditary spastic paraplegia (ARHSP) with thin corpus callosum (TCC) is a common and clinically distinct form of familial spastic paraplegia that is linked to the SPG11 locus on chromosome 15 in most affected families. We analyzed 12 ARHSP-TCC families, refined the SPG11 candidate interval and identified ten mutations in a previously unidentified gene expressed ubiquitously in the nervous system but most prominently in the cerebellum, cerebral cortex, hippocampus and pineal gland. The mutations were either nonsense or insertions and deletions leading to a frameshift, suggesting a loss-of-function mechanism. The identification of the function of the gene will provide insight into the mechanisms leading to the degeneration of the corticospinal tract and other brain structures in this frequent form of ARHSP

Cellular responses of Candida albicans to phagocytosis and the extracellular activities of neutrophils are critical to counteract carbohydrate starvation, oxidative and nitrosative stress

Acknowledgments We thank Alexander Johnson (yhb1D/D), Karl Kuchler (sodD/D mutants), Janet Quinn (hog1D/D, hog1/cap1D/D, trx1D/D) and Peter Staib (ssu1D/D) for providing mutant strains. We acknowledge helpful discussions with our colleagues from the Microbial Pathogenicity Mechanisms Department, Fungal Septomics and the Microbial Biochemistry and Physiology Research Group at the Hans Kno¨ll Institute (HKI), specially Ilse D. Jacobsen, Duncan Wilson, Sascha Brunke, Lydia Kasper, Franziska Gerwien, Sea´na Duggan, Katrin Haupt, Kerstin Hu¨nniger, and Matthias Brock, as well as from our partners in the FINSysB Network. Author Contributions Conceived and designed the experiments: PM HW IMB AJPB OK BH. Performed the experiments: PM CD HW. Analyzed the data: PM HW IMB AJPB OK BH. Wrote the paper: PM HW OK AJPB BH.Peer reviewedPublisher PD

POLG2 deficiency causes adult-onset syndromic sensory neuropathy, ataxia and parkinsonism

Objective: Mitochondrial dysfunction plays a key role in the pathophysiology of neurodegenerative disorders such as ataxia and Parkinson's disease. We describe an extended Belgian pedigree where seven individuals presented with adult-onset cerebellar ataxia, axonal peripheral ataxic neuropathy, and tremor, in variable combination with parkinsonism, seizures, cognitive decline, and ophthalmoplegia. We sought to identify the underlying molecular etiology and characterize the mitochondrial pathophysiology of this neurological syndrome. Methods: Clinical, neurophysiological, and neuroradiological evaluations were conducted. Patient muscle and cultured fibroblasts underwent extensive analyses to assess mitochondrial function. Genetic studies including genome-wide sequencing were conducted. Results: Hallmarks of mitochondrial dysfunction were present in patients' tissues including ultrastructural anomalies of mitochondria, mosaic cytochrome c oxidase deficiency, and multiple mtDNA deletions. We identified a splice acceptor variant in POLG2, c.970-1G>C, segregating with disease in this family and associated with a concomitant decrease in levels of POLG2 protein in patient cells. Interpretation: This work extends the clinical spectrum of POLG2 deficiency to include an overwhelming, adult-onset neurological syndrome that includes cerebellar syndrome, peripheral neuropathy, tremor, and parkinsonism. We therefore suggest to include POLG2 sequencing in the evaluation of ataxia and sensory neuropathy in adults, especially when it is accompanied by tremor or parkinsonism with white matter disease. The demonstration that deletions of mtDNA resulting from autosomal-dominant POLG2 variant lead to a monogenic neurodegenerative multicomponent syndrome provides further evidence for a major role of mitochondrial dysfunction in the pathomechanism of nonsyndromic forms of the component neurodegenerative disorders

Clinical and genetic analysis of 29 Brazilian patients with Huntington’s disease-like phenotype

Huntington’s disease (HD) is a neurodegenerative disorder characterized by chorea, behavioral disturbances and dementia, caused by a pathological expansion of the CAG trinucleotide in the HTT gene. Several patients have been recognized with the typical HD phenotype without the expected mutation. The objective of this study was to assess the occurrence of diseases such as Huntington’s disease-like 2 (HDL2), spinocerebellar ataxia (SCA) 1, SCA2, SCA3, SCA7, dentatorubral-pallidoluysian atrophy (DRPLA) and choreaacanthocytosis (ChAc) among 29 Brazilian patients with a HD-like phenotype. In the group analyzed, we found 3 patients with HDL2 and 2 patients with ChAc. The diagnosis was not reached in 79.3% of the patients. HDL2 was the main cause of the HD-like phenotype in the group analyzed, and is attributable to the African ancestry of this population. However, the etiology of the disease remains undetermined in the majority of the HD negative patients with HD-like phenotype. Key words: Huntington’s disease, Huntington’s disease-like, chorea-acanthocytosis, Huntington’s disease-like 2

CAG Repeats Determine Brain Atrophy in Spinocerebellar Ataxia 17: A VBM Study

Abnormal repeat length has been associated with an earlier age of onset and more severe disease progression in the rare neurodegenerative disorder spinocerebellar ataxia 17 (SCA17).To determine whether specific structural brain degeneration and rate of disease progression in SCA17 might be associated with the CAG repeat size, observer-independent voxel-based morphometry was applied to high-resolution magnetic resonance images of 16 patients with SCA17 and 16 age-matched healthy controls. The main finding contrasting SCA17 patients with healthy controls demonstrated atrophy in the cerebellum bilaterally. Multiple regression analyses with available genetic data and also post-hoc correlations revealed an inverse relationship again with cerebellar atrophy. Moreover, we found an inverse relationship between the CAG repeat length and rate of disease progression.Our results highlight the fundamental role of the cerebellum in this neurodegenerative disease and support the genotype-phenotype relationship in SCA17 patients. Genetic factors may determine individual susceptibility to neurodegeneration and rate of disease progression

Defects in the CAPN1 Gene Result in Alterations in Cerebellar Development and Cerebellar Ataxia in Mice and Humans

A CAPN1 missense mutation in Parson Russell Terrier dogs is associated with spinocerebellar ataxia. We now report that homozygous or heterozygous CAPN1-null mutations in humans result in cerebellar ataxia and limb spasticity in four independent pedigrees. Calpain-1 knockout (KO) mice also exhibit a mild form of ataxia due to abnormal cerebellar development, including enhanced neuronal apoptosis, decreased number of cerebellar granule cells, and altered synaptic transmission. Enhanced apoptosis is due to absence of calpain-1-mediated cleavage of PH domain and leucine-rich repeat protein phosphatase 1 (PHLPP1), which results in inhibition of the Akt pro-survival pathway in developing granule cells. Injection of neonatal mice with the indirect Akt activator, bisperoxovanadium, or crossing calpain-1 KO mice with PHLPP1 KO mice prevented increased postnatal cerebellar granule cell apoptosis and restored granule cell density and motor coordination in adult mice. Thus, mutations in CAPN1 are an additional cause of ataxia in mammals, including humans