Parkinson's disease patient-specific neuronal networks carrying the LRRK2 G2019S mutation unveil early functional alterations that predate neurodegeneration.

A deeper understanding of early disease mechanisms occurring in Parkinson's disease (PD) is needed to reveal restorative targets. Here we report that human induced pluripotent stem cell (iPSC)-derived dopaminergic neurons (DAn) obtained from healthy individuals or patients harboring LRRK2 PD-causing mutation can create highly complex networks with evident signs of functional maturation over time. Compared to control neuronal networks, LRRK2 PD patients' networks displayed an elevated bursting behavior, in the absence of neurodegeneration. By combining functional calcium imaging, biophysical modeling, and DAn-lineage tracing, we found a decrease in DAn neurite density that triggered overall functional alterations in PD neuronal networks. Our data implicate early dysfunction as a prime focus that may contribute to the initiation of downstream degenerative pathways preceding DAn loss in PD, highlighting a potential window of opportunity for pre-symptomatic assessment of chronic degenerative diseases.

Patient-specific iPSC-derived cellular models of LGMDR1.

Limb-girdle muscular dystrophy recessive 1 (LGMDR1) represents one of the most common types of LGMD in the population, where patients develop a progressive muscle degeneration. The disease is caused by mutations in calpain 3 gene, with over 500 mutations reported to date. However, the molecular events that lead to muscle wasting are not clear, nor the reasons for the great clinical variability among patients, and this has so far hindered the development of effective therapies. Here we generate human induced pluripotent stem cells (iPSCs) from skin fibroblasts of 2 healthy controls and 4 LGMDR1 patients with different mutations. The generated lines were able to differentiate into myogenic progenitors and myotubes in vitro and in vivo, upon a transient PAX7 overexpressing protocol. Thus, we have generated myogenic cellular models of LGMDR1 that harbor different CAPN3 mutations within a human genetic background, and which do not derive from muscular biopsies. These models will allow us to investigate disease mechanisms and test therapies. Despite the variability found among iPSC lines that was unrelated to CAPN3 mutations, we found that patient-derived myogenic progenitors and myotubes express lower levels of DMD, which codes a key protein in satellite cell regulation and myotube maturation.

Advanced cell-based modeling of the royal disease: characterization of the mutated F9 mRNA.

Essentials The Royal disease (RD) is a form of hemophilia B predicted to be caused by a splicing mutation. We generated an iPSC-based model of the disease allowing mechanistic studies at the RNA level. F9 mRNA analysis in iPSC-derived hepatocyte-like cells showed the predicted abnormal splicing. Mutated F9 mRNA level was very low but we also found traces of wild type transcripts. SUMMARY: Background The royal disease is a form of hemophilia B (HB) that affected many descendants of Queen Victoria in the 19th and 20th centuries. It was found to be caused by the mutation F9 c.278-3A>G. Objective To generate a physiological cell model of the disease and to study F9 expression at the RNA level. Methods Using fibroblasts from skin biopsies of a previously identified hemophilic patient bearing the F9 c.278-3A>G mutation and his mother, we generated induced pluripotent stem cells (iPSCs). Both the patient's and mother's iPSCs were differentiated into hepatocyte-like cells (HLCs) and their F9 mRNA was analyzed using next-generation sequencing (NGS). Results and Conclusion We demonstrated the previously predicted aberrant splicing of the F9 transcript as a result of an intronic nucleotide substitution leading to a frameshift and the generation of a premature termination codon (PTC). The F9 mRNA level in the patient's HLCs was significantly reduced compared with that of his mother, suggesting that mutated transcripts undergo nonsense-mediated decay (NMD), a cellular mechanism that degrades PTC-containing mRNAs. We also detected small proportions of correctly spliced transcripts in the patient's HLCs, which, combined with genetic variability in splicing and NMD machineries, could partially explain some clinical variability among affected members of the European royal families who had lifespans above the average. This work allowed the demonstration of the pathologic consequences of an intronic mutation in the F9 gene and represents the first bona fide cellular model of HB allowing the study of rare mutations at the RNA level.

Quantitative and qualitative normal regulatory T cells are not capable of inducing suppression in SLE patients due to T-cell resistance.

Previous reports have suggested that regulatory T cells (Treg) are abnormal in patients with systemic lupus erythematosus (SLE). In the present work, we quantified CD4+FOXP3+ Treg cells in patients with SLE and found no quantitative alterations. However, we found a clear defect in suppression assays. Surprisingly, SLE-derived Treg cells exhibited a normal phenotype and functional capacity. Conversely, SLE-derived CD4+CD25(-) effector T cells resisted suppression by autologous and allogeneic regulatory cells. Our findings strongly suggest that the defect in T-cell suppression observed in SLE is because of effector cell resistance and not because of an abnormal regulatory function.

Interleukin-6 and chemokines in the neuropsychiatric manifestations of systemic lupus erythematosus.

OBJECTIVE: To define the cytokine and chemokine profile in cerebrospinal fluid (CSF) from patients with neuropsychiatric systemic lupus erythematosus (NPSLE). METHODS: Forty-two SLE patients who had been hospitalized because of NP manifestations were studied. Patients were evaluated at hospitalization and 6 months later; a CSF sample was obtained at each evaluation. As controls, CSF from 6 SLE patients with septic meningitis, 16 SLE patients with no history of NP manifestations (non-NPSLE), and 25 patients with nonautoimmune diseases were also studied. Soluble molecules, including cytokines (interleukin-2 [IL-2], IL-4, IL-6, IL-10, tumor necrosis factor alpha [TNFalpha], and interferon-gamma [IFNgamma]) and chemokines (monocyte chemotactic protein 1 [MCP-1], RANTES, IL-8, monokine induced by IFNgamma [MIG], and interferon-gamma-inducible 10-kd protein [IP-10]), were measured with the use of cytometric bead array kits. RESULTS: CSF levels of the following molecules were significantly increased in NPSLE patients as compared with non-NPSLE and nonautoimmune diseases control patients, respectively: IL-6 (32.7 versus 3.0 and 2.96 pg/ml), IL-8 (102.8 versus 29.97 and 19.7 pg/ml), IP-10 (888.2 versus 329.7 [P not significant] and 133.6 pg/ml), RANTES (3.8 versus 2.5 and 2.2 pg/ml), MCP-1 (401.7 versus 257.9 [P not significant] and 136.9 pg/ml), and MIG (35.4 versus 11.4 and 3.5 pg/ml). Low levels of IL-2, IL-4, IL-10, TNFalpha, and IFNgamma were found in all groups. All cytokines and chemokines, except TNFalpha, were significantly higher among the SLE patients with septic meningitis than among the NPSLE patients. Six months later and in the absence of NP manifestations, all elevated molecule levels, except RANTES, in patients with NPSLE had decreased significantly, and no differences were noted between the NPSLE and non-NPSLE groups. CONCLUSION: A central nervous system response composed of IL-6 and chemokines, but not Th1/Th2 cytokines, is associated with NP manifestations in SLE patients.

Diminished expression of complement regulatory proteins (CD55 and CD59) in lymphocytes from systemic lupus erythematosus patients with lymphopenia.

CD55 and CD59 are glycophosphatidylinositol-anchored proteins with complement inhibitory properties. Lymphopenia in systemic lupus erythematosus (SLE) has been associated with autoantibodies targeting nuclear antigens. The aim of this study was to evaluate the surface density of CD55 and CD59 in T and B lymphocytes from patients with SLE and lymphopenia and its possible correlation with the presence of common SLE autoantibodies. Flow cytometric analyses were performed on CD55 and CD59 stained CD3+ and CD19+ cells from 40 SLE patients, 30 with lymphopenia and 10 without it, and 25 healthy controls. Autoantibodies were detected in the sera by enzyme linked immunosorbent assay. The mean fluorescence intensity of CD55 and CD59 in T and B cells was significantly diminished in SLE patients with lymphopenia when compared with healthy subjects. Interestingly, the opposite was found in T and B cells from non-lymphopenic SLE patients. Although there was no correlation between CD55 and CD59 surface density and the presence of any specificity of the autoantibodies tested, higher titres of anti-dsDNA, anti-SM and anti-ribosomal p antibodies were significantly associated with lymphopenia. The deficiency of CD55 and CD59 expression may play a role in the pathophysiology of lymphopenia, most likely by increasing the susceptibility of cells to complement mediated cytolysis.

The gut: beyond immunology

El sistema inmunitario se caracteriza principalmente por la capacidad de distinguir lo propio de lo extraño. En el intestino, el sistema inmunitario no sólo comparte esta propiedad, sino que es, además, apto para seleccionar los componentes nutritivos y/o benéficos de aquellos que pueden ser nocivos. Si se considera que el intestino es colonizado por bacterias comensales que contribuyen a la digestión y al control del crecimiento de microorganismos patógenos, no es sorprendente que sea la superficie mucosa el más extenso y, acaso, el más sofisticado de los compartimientos del sistema inmunitario. Así, las respuestas innata y adaptativa se suman a estructuras, células y mecanismos exquisitamente especializados, tales como el epitelio intestinal, las placas de Peyer, las células M, entre otros, que en conjunto son responsables del control dinámico de la homeostasis entre el intestino y su flora. La presente revisión versa sobre algunos conceptos populares sobre el aparato digestivo y hace hincapié en el papel del intestino como órgano inmunitario(AU)

The immune system is characterized by the ability to distinguish self from non-self. The intestinal immune system bears this latter property but, furthermore, it must discriminate among nutritious and beneficial substances from toxic or harmful ones. Considering that the gut has to be colonized by commensal bacteria participating in digestion as well as in the control of pathogen microorganisms, it is not surprising that mucosal surfaces are the largest and probably the most exquisitely specialized immune system’s compartment. This means that not only innate and adaptive immunity are present, but further, particular structures, cells, and mechanisms such as physical barrriers, epithelia, Peyer’s patches, M cells among others, which together are involved in the dynamic control of the homeostasis between gut and its flora. The present review deals with some popular conceptions about the digestive system with particular emphasis on the gut’s immunology(AU)

The gut: beyond immunology.

The immune system is characterized by the ability to distinguish self from non-self. The intestinal immune system bears this latter property but, furthermore, it must discriminate among nutritious and beneficial substances from toxic or harmful ones. Considering that the gut has to be colonized by commensal bacteria participating in digestion as well as in the control of pathogen microorganisms, it is not surprising that mucosal surfaces are the largest and probably the most exquisitely specialized immune system's compartment. This means that not only innate and adaptive immunity are present, but further, particular structures, cells, and mechanisms such as physical barrriers, epithelia, Peyer's patches, M cells among others, which together are involved in the dynamic control of the homeostasis between gut and its flora. The present review deals with some popular conceptions about the digestive system with particular emphasis on the gut's immunology.

Effect of rapamycin on cytokine profile in kidney transplant recipients treated with triple drug therapy.

UNLABELLED: The aim of this study was to explore differences in the cytokine profile among de novo kidney transplant recipients treated with either Rapamycin (Rapa) + cyclosporine (CsA) + prednisone (P) or CsA + azathioprine (Aza) + P. PATIENTS AND METHODS: Among the 13 adult kidney transplant recipients studied, seven received Rapa + CsA + P while the remaining six received CsA + Aza + P with their living donors serving as controls (n = 13). Spontaneous production of IL-2, IFNgamma, IL-10, and TGF-beta were measured by ELISA in supernatants from 24-hour cultured unstimulated peripheral blood mononuclear cell (PBMC) at time zero (the day before the transplant), and at 3 and 6 months posttransplant. Cytokines were also measured 1 month after CsA withdrawal in the Rapa + CsA + P group. RESULTS: From time zero to the end of the study, IL-2, IFNgamma, and IL-10 were present at low or undetectable levels in all three groups. TGF-beta tended to increase in supernatants from patients under Rapa + CsA + P at 6 months posttransplant and at 1 month after CsA withdrawal without correlation to Rapa blood levels. TGF-beta remained stable throughout the study period for patients included in the CsA + Aza + P group. There was no difference in this cytokine level between these study groups at any given time. CONCLUSIONS: This study showed no differences in the spontaneous cytokine profiles evaluated in patients treated with both therapeutic schemes.

CD8+ chronic lymphocytic leukemia: an extensive characterization of a bizarre hybrid neoplasia.

Atypical chronic lymphocytic leukemia (CLL) expressing the CD8 antigen have a frequency of less than 0.5% of all cases, however, they are not yet been fully characterized. Herein a CD8+ CLL case was extensively studied. Besides the classical CLL antigen expression, an unusual presence of surface markers such as CD11c, CD56, and CD154 was observed. Moreover, gene expression of chemokine receptors belonging to the CCR family were clearly evidenced as well as mRNA for both, Th1 and Th2 cytokines. Likewise, granzyme A, B and perforin gene expression, cytotoxic T cell or NK enzymes were found. The intricate profile of membrane molecules and gene expression suggest that it could be favorable, rather than deletereous, for the maintainance of the neoplastic process.

Immunoregulatory defects in patients with systemic lupus erythematosus in clinical remission.

Little is known about the immune system of patients with systemic lupus erythematosus (SLE) during periods of silent disease. To address this issue we analysed lymphoid populations andcytokine production of mononuclear cells obtained from SLE patients in remission. We studied 43 patients with inactive disease, 10 with active disease and 30 controls. Remission was defined as at least 1 year during which lack of clinical disease activity permitted withdrawal of all treatment. Remission length ranged from 1 to 30 years. Flow cytometry and ELISA were used to study lymphoid populations (CD4, CD8 and CD19) and cytokine production (IL-2, 4, 10, 12 and 18). Patients with short remission periods (up to 15 years) exhibited an increased percentage of B cells; production of IL-2, IL-10 and IL-12 was decreased; production of IL-18 was increased. Interestingly, patients from groups with long time of inactive disease had corrected most alterations, but had an impaired IL-18 expression. IL-12 production correlated strongly with the length of the remission period (r = 0.7565). The immune system of patients with inactive lupus has partially corrected the disturbances present during disease activity. This is accomplished gradually, sometimes until counter-regulatory alterations are developed. This may allow patients to remain without disease activity.

Bacterial DNA in synovial fluid cells of patients with juvenile onset spondyloarthropathies.

OBJECTIVE: To identify bacterial DNA in synovial fluid cells of patients with active juvenile onset spondyloarthropathy (SpA). METHODS: The main group of study constituted 22 patients with juvenile onset SpA. In addition, five patients with adult onset SpA and nine with rheumatoid arthritis (RA) were studied. Polymerase chain reaction (PCR) with either genus- or species-specific primers was performed on synovial fluid cells to detect DNA sequences of Chlamydia trachomatis, Yersinia enterocolitica, Salmonella sp., Shigella sp., Campylobacter sp. and Mycobacterium tuberculosis. The presence of antibacterial antibodies in sera and synovial fluid was also determined by enzyme-linked immunoassay. RESULTS: The synovial fluid of nine patients with juvenile onset SpA, three with adult onset SpA and one with RA contained bacterial DNA. Five juvenile onset SpA samples had DNA of one single bacterium; two juvenile onset SpA and three adult onset SpA had DNA of two bacteria and two juvenile onset SpA had DNA of three bacteria. Overall, Salmonella sp. DNA was detected in seven synovial fluid samples, Shigella sp., Campylobacter sp. and M. tuberculosis were found in four samples each, and C. trachomatis was found in two. The bacterial DNA findings correlated with neither diagnosis nor disease duration. One RA synovial fluid had DNA of Campylobacter sp. Neither serum nor synovial fluid antibacterial antibodies correlated with DNA findings or clinical diagnosis. CONCLUSION: In this study, single and several combinations of bacterial DNA were identified in the synovial fluid of patients with long-term undifferentiated and definite juvenile onset SpA and adult onset SpA. Of relevance is that bacterial DNA corresponds to bacteria producing endemic disease in our population.

Innate immune mechanisms in the pathogenesis of systemic lupus erythematosus (SLE).

Immune imbalance in SLE increases the susceptibility to infectious diseases. The aim of this study was to analyze several mechanisms related to non-specific immunity in this autoimmune disorder. We studied in vivo CD11b expression, phagocytosis, and chemotaxis in polymorphonuclear cells (PMN) from SLE patients. All tests were also performed under hrIL-8 stimulating conditions and analyzed by flow cytometry. Intracellular leucocyte (monocytes and PMN) enzyme activity was evaluated using specific substrates for cathepsin B and D, collagenase, and oxidative burst by flow cytoenzymology. An exaggerated in vivo CD11b expression was observed on PMN from SLE patients without noticeably in vitro effect upon hrIL-8. Similarly both, phagocytosis and chemotaxis were diminished and showed no response to hrIL-8 stimulation. The opposite was found in PMN from controls. Intracellular enzyme activity was comparable between groups as far as cathepsin B and D are concerned. A tendency of decreased oxidative-burst induction was noted in monocytes and PMN from SLE patients, whereas collagenase activity was found clearly increased in both leucocyte subpopulations. Our results may represent a deficient ability of the innate immune mechanisms for the clearance of infectious agents, immune complexes, satisfactory resolution of inflammatory processes and tissue repair in SLE.

Innate immune response mechanisms in non-insulin dependent diabetes mellitus patients assessed by flow cytoenzymology.

It is well known that infections in patients with diabetes mellitus are more severe, although there is controversy for increased susceptibility to them. Non-specific immune response mechanisms could be related to defense and/or susceptibility to pathogens. The aim of this study was to investigate the activity of several enzymes involved in the primary host defense mechanisms in non-insulin dependent diabetes mellitus (NIDDM). Twenty NIDDM females with a mean HbA(1c) level of 8.19% were included. No patient had clinical evidence of infection. As controls 20 healthy females were studied. The enzymes tested were dipeptidyl-peptidase I (DPP-I), cathepsin B and D, NADPH oxidase and superoxide dismutase (oxidative burst) and collagenase. Isolated leukocytes were incubated with the specific substrates in pyrogen free conditions. The intracellular enzyme activity was analyzed by flow cytometry. Collagenase enzymatic activity was similar in the three leukocyte subpopulations studied. Oxidative burst induction in monocytes was comparable between both groups. Enzyme activity of cathepsin B and D in all cell subsets, oxidative burst in PMN cells, and DPP-I in lymphocytes and monocytes from patients, was higher than those from healthy females (P<0.05). Overall, our findings demonstrate an enhanced functional status of several intracellular leukocyte enzymes in NIDDM. Furthermore, the increased oxidative burst induction and the consequent production of free radicals, may contribute to vascular complications. Other mechanisms - either from the non-specific or specific immune response - deserve investigation to establish if diabetic patients are more susceptible to infectious diseases.

Clinical and biologic effects of anti-interleukin-10 monoclonal antibody administration in systemic lupus erythematosus.

OBJECTIVE: To evaluate the safety and clinical efficacy of administering an anti-interleukin-10 (anti-IL-10) monoclonal antibody (mAb) to systemic lupus erythematosus (SLE) patients with active and steroid-dependent disease. In addition, we sought to assess the effects of in vivo IL-10 neutralization on biologic markers of SLE. METHODS: Treatment consisted of 20 mg/day intravenous administration of an anti-IL-10 murine mAb (B-N10) for 21 consecutive days, with a followup period of 6 months. Six patients were studied. RESULTS: Treatment was safe and well tolerated. All patients developed antibodies against B-N10. Cutaneous lesions and joint symptoms improved in all patients beginning during B-N10 administration and continuing to month 6. The SLE Disease Activity Index decreased from a mean +/- SEM of 8.83+/-0.91 on day 1 to 3.67+/-0.67 on day 21 (P = 0.001), 1.50+/-0.84 at month 2, and 1.33+/-0.80 at month 6 (P<0.001). At the end of followup, the disease was clinically inactive in 5 of the 6 patients. Prednisone administration was decreased from a mean +/- SEM of 27.9+/-5.7 mg/day on day 1 to 9.6+/-2.0 mg/day at month 6 (P<0.005). Activity of immune and endothelial cells rapidly decreased, as assessed by the early evolution of several biologic markers. CONCLUSION: This is the first report of IL-10 antagonist administration to humans. The study shows the involvement of IL-10 in the pathogenesis of SLE, and indicates that the use of IL-10 antagonists may be beneficial in the management of refractory SLE.

Multidrug resistance-1 (MDR-1) in rheumatic autoimmune disorders. Part I: Increased P-glycoprotein activity in lymphocytes from rheumatoid arthritis patients might influence disease outcome.

BACKGROUND: Multidrug resistance (MDR) is characterized by overexpression of P-glycoprotein, a pump molecule that decreases intracellular drug concentrations by increasing drug efflux from cells. OBJECTIVE: To look for correlations between clinical status and P-glycoprotein activity and/or TNF-alpha mRNA levels in patients with rheumatoid arthritis. METHODS: Sixteen patients were studied. Based on response to therapy, eight were refractory and eight nonrefractory to treatment. Findings were compared to those in 24 healthy controls. Flow cytometry was used to evaluate P-glycoprotein activity in peripheral blood mononuclear cells isolated by gradient centrifugation and incubated with the P-glycoprotein substrate daunorubicin. TNF-alpha mRNA levels were determined using quantitative PCR. RESULTS: Patients with rheumatoid arthritis showed an increased number of lymphocytes with high P-glycoprotein activity (p = 0.0001) as compared to the normal controls. P-glycoprotein activity was higher in the refractory than in the non-refractory patient subgroup (p = 0.006). Also, TNF-alpha mRNA levels were markedly higher in the refractory subgroup than in the nonrefractory subgroup, and were undetectable in the normal controls. CONCLUSIONS: Enhanced P-glycoprotein activity may be closely related to an unfavorable clinical course and a poor response to treatment. Increased TNF-alpha expression and chronic exposure to various drugs, including glucocorticoids, may contribute to increase P-glycoprotein activity. Both high P-glycoprotein activity and excessive amounts of TNF-alpha seem associated with poor outcome in rheumatoid arthritis.