Expression ratios of the Bcl-2 family proteins and disease activity in multiple sclerosis

Sirtuins and Metabolism Biomarkers in Relapsing-Remitting and Secondary Progressive Multiple Sclerosis: a Correlation Study with Clinical Outcomes and Cognitive Impairments

Multiple sclerosis (MS) is a primary inflammatory demyelinating disease with different clinical courses and subtypes. The present study aimed to determine whether mitochondrial dysfunction and sirtuins 1 and 3, as metabolism and epigenetic modifying factors, might contribute to MS disease progression measured by physical disability and cognitive impairment.The volunteers (n = 20 controls, n = 59 MS) were recruited and assessed for cognitive function and disability scores; then, patients were clinically classified as relapsing-remitting (RR) in remission phase, RR in relapse phase, and secondary progressive MS. We measured sirtuin (SIRT) 1 and 3 levels, mitochondrial complex I, IV, aconitase, and α-ketoglutarate dehydrogenase (α-KGD) activity in the peripheral blood mononuclear cells (PBMCs). Furthermore, SIRT1, pyruvate, lactate, and cytochrome c (Cyt c) were determined in plasma. Finally, we performed postmortem tissue immunohistochemistry to assess the level of SIRT1 and SIRT3 in the brain lesions of patients with MS.Increased disability and cognitive impairment in patients were correlated. Plasma level of lactate showed a correlation with the disability in MS patients; moreover, a trend toward increased Cyt c plasma level was observed. Investigation of PBMCs exhibited decreased SIRT1 during the relapse phase along with a reduced complex IV activity in all MS subgroups. α-KGD activity was significantly increased in the RR-remission, and SIRT3 was elevated in RR-relapse group. This elevation correlated with disability and cognitive impairment. Finally, immunohistochemistry demonstrated increased levels of SIRT1 and 3 in the brain active lesion of patients with MS.Our data suggest that mitochondrial dysfunction and alteration in some epigenetics and metabolism modifying factors in the CNS and peripheral blood cells may contribute or correlate with MS progression.

Combined laser-activated SVF and PRP remodeled spinal sclerosis via activation of Olig-2, MBP, and neurotrophic factors and inhibition of BAX and GFAP

A single injection of platelet-rich plasma (PRP) or stromal vascular fraction (SVF) in treating neurological ailments suggests promise; however, there is limited evidence of the efficacy of combination therapy. This trial aimed to determine whether combining SVF and PRP could provide further therapeutic effects in treating multiple sclerosis (MS). Fifteen Persian cats were separated into three groups (n = 5): group I (control negative), and group II (control positive); EB was injected intrathecally into the spinal cord and then treated 14 days later with intrathecal phosphate buffered saline injection, and group III (SVF + PRP), cats were injected intrathecally with EB through the spinal cord, followed by a combination of SVF and PRP 14 days after induction. Therapeutic effects were evaluated using the Basso-Beattie-Bresnahan scale throughout the treatment timeline and at the end. Together with morphological, MRI scan, immunohistochemical, transmission electron microscopy, and gene expression investigations. The results demonstrated that combining SVF and PRP successfully reduced lesion intensity on gross inspection and MRI. In addition to increased immunoreactivity to Olig2 and MBP and decreased immunoreactivity to Bax and GFAP, there was a significant improvement in BBB scores and an increase in neurotrophic factor (BDNF, NGF, and SDF) expression when compared to the positive control group. Finally, intrathecal SVF + PRP is the most promising and safe therapy for multiple sclerosis, resulting in clinical advantages such as functional recovery, MRI enhancement, and axonal remyelination.

Circulating miRNAs as Potential Biomarkers Distinguishing Relapsing-Remitting from Secondary Progressive Multiple Sclerosis. A Review

Multiple sclerosis (MS) is a debilitating neurodegenerative, highly heterogeneous disease with a variable course. The most common MS subtype is relapsing–remitting (RR), having interchanging periods of worsening and relative stabilization. After a decade, in most RR patients, it alters into the secondary progressive (SP) phase, the most debilitating one with no clear remissions, leading to progressive disability deterioration. Among the greatest challenges for clinicians is understanding disease progression molecular mechanisms, since RR is mainly characterized by inflammatory processes, while in SP, the neurodegeneration prevails. This is especially important because distinguishing RR from the SP subtype early will enable faster implementation of appropriate treatment. Currently, the MS course is not well-correlated with the biomarkers routinely used in clinical practice. Despite many studies, there are still no reliable indicators correlating with the disease stage and its activity degree. Circulating microRNAs (miRNAs) may be considered valuable molecules for the MS diagnosis and, presumably, helpful in predicting disease subtype. MiRNA expression dysregulation is commonly observed in the MS course. Moreover, knowledge of diverse miRNA panel expression between RRMS and SPMS may allow for deterring disability progression through successful treatment. Therefore, in this review, we address the current state of research on differences in miRNA panel expression between the phases.

Contribution of Apaf-1 to the pathogenesis of cancer and neurodegenerative diseases

Deregulation of apoptosis is associated with various pathologies, such as neurodegenerative disorders at one end of the spectrum and cancer at the other end. Generally speaking, differentiated cells like cardiomyocytes, skeletal myocytes and neurons exhibit low levels of Apaf-1 (Apoptotic protease activating factor 1) protein suggesting that down-regulation of Apaf-1 is an important event contributing to the resistance of these cells to apoptosis. Nonetheless, upregulation of Apaf-1 has not emerged as a common phenomenon in pathologies associated with enhanced neuronal cell death, i.e., neurodegenerative diseases. In cancer, on the other hand, Apaf-1 downregulation is a common phenomenon, which occurs through various mechanisms including mRNA hyper-methylation, gene methylation, Apaf-1 localization in lipid rafts, inhibition by microRNAs, phosphorylation, and interaction with specific inhibitors. Due to the diversity of these mechanisms and involvement of other factors, defining the exact contribution of Apaf-1 to the development of cancer in general and neurodegenerative disorders, in particular, is complicated. The current review is an attempt to provide a comprehensive image of Apaf-1's contribution to the pathologies observed in cancer and neurodegenerative diseases with the emphasis on the therapeutic aspects of Apaf-1 as an important target in these pathologies.

Immunomodulatory and protective effects of interleukin-4 on the neuropathological alterations induced by a potassium channel blocker

The pathophysiology of neurological diseases related to potassium-channel dysfunction such as epilepsy is increasingly linked to immune system modulation. However, there are limited reports of which interleukin-4 (IL-4) can act on the neuroinflammatory response after seizure. Hence, we evaluated the effect of IL-4 in murine model of neuroexcitotoxcity using kaliotoxin (KTx), a potassium-channel blocker. Results showed that IL-4 treatment can significantly reduce the neuronal death induced by KTx. Probably by decreasing mitochondria swelling, reversing oxidative damage and enhancing Bcl-2 expression. Furthermore, IL-4 treatment significantly reduced TNF-α expression and enhanced GFAP and IL-10 expressions in the brain. IL-4 can be neuroprotective in epileptogenesis.

Defective expression of apoptosis-related molecules in multiple sclerosis patients is normalized early after autologous haematopoietic stem cell transplantation

Defective apoptosis might be involved in the pathogenesis of multiple sclerosis (MS). We evaluated apoptosis-related molecules in MS patients before and after autologous haematopoietic stem cell transplantation (AHSCT) using BCNU, Etoposide, AraC and Melphalan (BEAM) or cyclophosphamide (CY)-based conditioning regimens. Patients were followed for clinical and immunological parameters for 2 years after AHSCT. At baseline, MS patients had decreased proapoptotic BAD, BAX and FASL and increased A1 gene expression when compared with healthy counterparts. In the BEAM group, BAK, BIK, BIM_EL , FAS, FASL, A1, BCL2, BCLX_L , CFLIP_L and CIAP2 genes were up-regulated after AHSCT. With the exception of BIK, BIM_EL and A1, all genes reached levels similar to controls at day + 720 post-transplantation. Furthermore, in these patients, we observed increased CD8⁺ Fas⁺ T cell frequencies after AHSCT when compared to baseline. In the CY group, we observed increased BAX, BCLW, CFLIP_L and CIAP1 and decreased BIK and BID gene expressions after transplantation. At day + 720 post-AHSCT, the expression of BAX, FAS, FASL, BCL2, BCLX_L and CIAP1 was similar to that of controls. Protein analyses showed increased Bcl-2 expression before transplantation. At 1 year post-AHSCT, expression of Bak, Bim, Bcl-2, Bcl-xL and cFlip-L was decreased when compared to baseline values. In summary, our findings suggest that normalization of apoptosis-related molecules is associated with the early therapeutic effects of AHSCT in MS patients. These mechanisms may be involved in the re-establishment of immune tolerance during the first 2 years post-transplantation.

Identifying Causal Genes at the Multiple Sclerosis Associated Region 6q23 Using Capture Hi-C

Background

The chromosomal region 6q23 has been found to be associated with multiple sclerosis (MS) predisposition through genome wide association studies (GWAS). There are four independent single nucleotide polymorphisms (SNPs) associated with MS in this region, which spans around 2.5 Mb. Most GWAS variants associated with complex traits, including these four MS associated SNPs, are non-coding and their function is currently unknown. However, GWAS variants have been found to be enriched in enhancers and there is evidence that they may be involved in transcriptional regulation of their distant target genes through long range chromatin looping.

Aim

The aim of this work is to identify causal disease genes in the 6q23 locus by studying long range chromatin interactions, using the recently developed Capture Hi-C method in human T and B-cell lines. Interactions involving four independent associations unique to MS, tagged by rs11154801, rs17066096, rs7769192 and rs67297943 were analysed using Capture Hi-C Analysis of Genomic Organisation (CHiCAGO).

Results

We found that the pattern of chromatin looping interactions in the MS 6q23 associated region is complex. Interactions cluster in two regions, the first involving the rs11154801 region and a second containing the rs17066096, rs7769192 and rs67297943 SNPs. Firstly, SNPs located within the AHI1 gene, tagged by rs11154801, are correlated with expression of AHI1 and interact with its promoter. These SNPs also interact with other potential candidate genes such as SGK1 and BCLAF1. Secondly, the rs17066096, rs7769192 and rs67297943 SNPs interact with each other and with immune-related genes such as IL20RA, IL22RA2, IFNGR1 and TNFAIP3. Finally, the above-mentioned regions interact with each other and therefore, may co-regulate these target genes.

Conclusion

These results suggest that the four 6q23 variants, independently associated with MS, are involved in the regulation of several genes, including immune genes. These findings could help understand mechanisms of disease and suggest potential novel therapeutic targets.

Analysis of apoptosis-related genes in patients with clinically isolated syndrome and their association with conversion to multiple sclerosis

To analyse whether the expression of apoptotic transcripts is associated with the conversion from clinically isolated syndrome (CIS) to multiple sclerosis (MS). Eleven candidate transcripts belonging to the death receptor pathway, BCL-2, the inflammasome complex and NF-ΚB family were studied in the nonconverting and converting CIS patients during the four-year follow-up period. Conversion to MS was associated with marked variability in the expression of proapoptotic genes that were linked to TGF-B1 gene levels. The predominant expression of proapoptotic genes in patients with CIS suggests an increased potential to undergo apoptosis with the goal of terminating immune responses and regulating immune system homeostasis.

Up-regulation of fas and fasL pro-apoptotic genes expression in type 1 diabetes patients after autologous haematopoietic stem cell transplantation

Type 1 diabetes (T1D) is a chronic autoimmune disease characterized by T cell-mediated destruction of pancreatic β cells, resulting in insulin deficiency and hyperglycaemia. Recent studies have described that apoptosis impairment during central and peripheral tolerance is involved in T1D pathogenesis. In this study, the apoptosis-related gene expression in T1D patients was evaluated before and after treatment with high-dose immunosuppression followed by autologous haematopoietic stem cell transplantation (HDI-AHSCT). We also correlated gene expression results with clinical response to HDI-AHSCT. We observed a decreased expression of bad, bax and fasL pro-apoptotic genes and an increased expression of a1, bcl-x(L) and cIAP-2 anti-apoptotic genes in patients' peripheral blood mononuclear cells (PBMCs) compared to controls. After HDI-AHSCT, we found an up-regulation of fas and fasL and a down-regulation of anti-apoptotic bcl-x(L) genes expression in post-HDI-AHSCT periods compared to pre-transplantation. Additionally, the levels of bad, bax, bok, fasL, bcl-x(L) and cIAP-1 genes expression were found similar to controls 2 years after HDI-AHSCT. Furthermore, over-expression of pro-apoptotic noxa at 540 days post-HDI-AHSCT correlated positively with insulin-free patients and conversely with glutamic acid decarboxylase autoantibodies (GAD65) autoantibody levels. Taken together, the results suggest that apoptosis-related genes deregulation in patients' PBMCs might be involved in breakdown of immune tolerance and consequently contribute to T1D pathogenesis. Furthermore, HDI-AHSCT modulated the expression of some apoptotic genes towards the levels similar to controls. Possibly, the expression of these apoptotic molecules could be applied as biomarkers of clinical remission of T1D patients treated with HDI-AHSCT therapy.

miR-15a and 16-1 are downregulated in CD4+ T cells of multiple sclerosis relapsing patients

The pathology of relapsing-remitting multiple sclerosis (RR-MS) is largely attributed to activated autoreactive effector T lymphocytes. The influence of microRNAs on the immune response has been shown to occur in different pathways of lymphocyte differentiation and function. Here, the expression of the miRNAs miR-15a/16-1 in PBMC, CD4(+), and CD8(+) from RR-MS patients has been investigated. BCL2, a known miR-15a/16-1 target, has also been analyzed. The results have shown that miR-15a/16-1 is downregulated in CD4(+) T cells, whereas BCL2 is highly expressed in RR-MS patients only. Our data suggest that miR-15a/16-1 can also modulate the BCL2 gene expression in CD4(+) T cells from RR-MS patients, thereby affecting apoptosis processes.

Aberrant expression of the apoptosis-related proteins BAK and MCL1 in T cells in multiple sclerosis

Pathogenic T cells of multiple sclerosis (MS) patients have been suggested to be endowed with an increased resistance to apoptosis, contributing to their increased survival. We report herein increased levels of the anti-apoptotic MCL1 protein and its half-life in activated lymphocytes of MS patients, which were not associated with differences in MCL1 RNA levels or with alterations in the expression levels of the known E3 ligases of MCL1-β-TrCP and HUWE1. Concomitantly, the expression levels of the pro-apoptotic protein BAK were decreased in MS patients at relapse. These findings suggest the dysregulation of the apoptosis-related proteins MCL1 and BAK in MS.

Characterization of immune cell subsets during the active phase of multiple sclerosis reveals disease and c-Jun N-terminal kinase pathway biomarkers

BACKGROUND

Autoimmune activation and deregulated apoptosis of T lymphocytes are involved in multiple sclerosis (MS). c-Jun N-terminal kinase (JNK) plays a role in T-cell survival and apoptosis.

OBJECTIVES

The aim of this work was to investigate the role of the JNK-dependent apoptosis pathway in relapsing-remitting MS (RRMS).

METHODS

The immunomodulatory effect of AS602801, a JNK inhibitor, was firstly evaluated on activated peripheral blood mononuclear cells (PBMCs) from healthy volunteers (HVs) and secondly in unstimulated purified CD4+, CD8+ and CD11b+ cells from RRMS patients and HVs. Moreover JNK/inflammation/apoptosis related genes were investigated in RRMS and HV samples.

RESULTS

In activated PBMCs from HVs, we showed that AS602801 blocked T-lymphocyte proliferation and induced apoptosis. In RRMS CD4+ and CD8+ cells, AS602801 induced apoptosis genes and expression of surface markers, while in RRMS CD11b+ cells it induced expression of innate immunity receptors and co-stimulatory molecules. Untreated cells from RRMS active-phase patients significantly released interleukin-23 (IL-23) and interferon-gamma (IFN-γ) and expressed less apoptosis markers compared to the cells of HVs. Moreover, gene expression was significantly different in cells from RRMS active-phase patients vs. HVs. By comparing RRMS PBMCs in the active and stable phases, a specific genomic signature for RRMS was indentified. Additionally, CASP8AP2, CD36, ITGAL, NUMB, OLR1, PIAS-1, RNASEL, RTN4RL2 and THBS1 were identified for the first time as being associated to the active phase of RRMS.

CONCLUSIONS

The analysis of the JNK-dependent apoptosis pathway can provide biomarkers for activated lymphocytes in the active phase of RRMS and a gene expression signature for disease status. The reported results might be useful to stratify patients, thereby supporting the development of novel therapies.

Is the modulatory effect of pregnancy in multiple sclerosis associated with changes in blood apoptotic molecules?

OBJECTIVE

We examined whether the modulatory effect of pregnancy on multiple sclerosis (MS) is associated with changes in the apoptotic molecules in sera.

SUBJECTS AND METHODS

The serum levels of tumor necrosis factor-related apoptosis-inducing ligand (sTRAIL), sFas, Fas ligand (sFasL) and macrophage migration inhibitory factor were analyzed from 19 MS patients and 14 controls during late pregnancy and post-partum. The obtained results were related to disease activity and the progression of MS.

RESULTS

Disease activity decreased during pregnancy. The levels of sTRAIL and sFasL increased from late pregnancy to post-partum situation in both MS patients and controls, but in MS patients the changes in the levels of sTRAIL from late pregnancy to post-partum were smaller than in controls.

CONCLUSIONS

Post-partum upregulation of TRAIL and FasL seems to be caused by physiologic reactivation of the mother's immune system after pregnancy. An increased risk of relapses in MS post-partum may be associated with changes in the immunomodulatory potential of these apoptotic molecules.

Preferential killing of cancer cells with mitochondrial dysfunction by natural compounds

Mitochondria play essential roles in cellular metabolism, redox homeostasis, and regulation of cell death. Emerging evidences suggest that cancer cells exhibit various degrees of mitochondrial dysfunctions and metabolic alterations, which may serve as a basis to develop therapeutic strategies to preferentially kill the malignant cells. Mitochondria as a therapeutic target for cancer treatment is gaining much attention in the recent years, and agents that impact mitochondria with anticancer activity have been identified and tested in vitro and in vivo using various experimental systems. Anticancer agents that directly target mitochondria or indirectly affect mitochondrial functions are collectively classified as mitocans. This review article focuses on several natural compounds that preferentially kill cancer cells with mitochondrial dysfunction, and discusses the possible underlying mechanisms and their therapeutic implications in cancer treatment. Mitocans that have been comprehensively reviewed recently are not included in this article. Important issues such as therapeutic selectivity and the relevant biochemical basis are discussed in the context of future perspectives.

Involvement of mTOR kinase in cytokine-dependent microglial activation and cell proliferation

Neuroinflammation plays a prominent role in the pathophysiology of several neurodegenerative disorders, including Multiple Sclerosis. Reactive microglial cells are always found in areas of active demyelination as well as in normal-appearing white matter. Microglia contribute to initiating and maintaining brain inflammation, and once activated release pro-inflammatory mediators potentially cytotoxic, like nitric oxide (NO). It is now evident that the mTOR signaling pathway regulates different functions in the innate immune system, contributing to macrophage activation. More recently, mTOR has been found to enhance the survival of EOC2 microglia during oxygen-glucose deprivation and increase NO synthase 2 (NOS2) expression during hypoxia in BV2 microglial cell line, thus suggesting an involvement in microglial pro-inflammatory activation. In the present study, we detected mTOR activation in response to two different stimuli, namely LPS and a mixture of cytokines, in primary cultures of rat cortical microglia. Moreover, mTOR inhibitors reduced NOS activity and NOS2 expression induced by cytokines, but not those induced by LPS. The mTOR inhibitor RAD001, in combination with cytokines, also reduced microglial proliferation and the intracellular levels of cyclooxygenase. Under basal conditions mTOR inhibition significantly reduced microglial viability. Interestingly, mTOR inhibitors did not display any relevant effect on astrocyte NOS2 activity or cell viability. In conclusion, mTOR selectively controls microglial activation in response to pro-inflammatory cytokines and appears to play a crucial role in microglial viability; thus these drugs may be a useful pharmacological tool to reduce neuroinflammation.

MS and clinically isolated syndromes: shared specificity but diverging clonal patterns of virus-specific IgG antibodies produced in vivo and by CSF B cells in vitro

BACKGROUND

Intrathecal synthesis of oligoclonal IgG antibodies against measles virus (MeV), varicella zoster virus (VZV) and herpes simplex virus type-1 (HSV-1) is a characteristic feature multiple sclerosis (MS).

METHODS

We have used isoelectric focusing-immunoblot to define the clonal patterns of IgG and of IgG antibodies to MeV, VZV and HSV-1 in supernatants of in vitro cultures of peripheral blood lymphocytes (PBL) and cerebrospinal fluid (CSF) cells and in sera and CSF from three patients with MS and three patients with clinically isolated syndromes (CIS) suspective of demyelinating disease.

RESULTS

In vitro synthesis of IgG by PBL was not detected in any patient. In contrast, in vitro synthesis by CSF cells of oligoclonal IgG and oligoclonal IgG antibodies to one or two of the three viruses tested was observed in all six patients. The clonal patterns of the in vitro synthesized IgG and virus specific IgG differed to varying extent from those synthesized intrathecally in vivo. However, in each patient, the in vitro and in vivo intrathecally produced antibodies displayed specificity for the same viruses. The addition of B cell activating factor (BAFF) had no effect on the amounts or clonal patterns of either total IgG or virus-specific IgG produced by CSF cells in vitro.

CONCLUSION

Virus specific B cells capable of spontaneous IgG synthesis are clonally expanded in the CSF of patients with MS. The B-cell repertoire in CSF samples is only partially representative of the intrathecal B-cell repertoire.

Therapeutic modulation of apoptosis: targeting the BCL-2 family at the interface of the mitochondrial membrane

A vast portion of human disease results when the process of apoptosis is defective. Disorders resulting from inappropriate cell death range from autoimmune and neurodegenerative conditions to heart disease. Conversely, prevention of apoptosis is the hallmark of cancer and confounds the efficacy of cancer therapeutics. In the search for optimal targets that would enable the control of apoptosis, members of the BCL-2 family of anti- and pro-apoptotic factors have figured prominently. Development of BCL-2 antisense approaches, small molecules, and BH3 peptidomimetics has met with both success and failure. Success-because BCL-2 proteins play essential roles in apoptosis. Failure-because single targets for drug development have limited scope. By examining the activity of the BCL-2 proteins in relation to the mitochondrial landscape and drawing attention to the significant mitochondrial membrane alterations that ensue during apoptosis, we demonstrate the need for a broader based multi-disciplinary approach for the design of novel apoptosis-modulating compounds in the treatment of human disease.

Glatiramer acetate in multiple sclerosis: a review

Multiple sclerosis (MS) is considered to be primarily an inflammatory autoimmune disease. Over the last 5 years, our view of the pathogenesis of MS has evolved considerably. The axonal damage was recognized as an early event in the disease process and as an important determinant of long-term disability. Therefore, the antiinflammatory and neuroprotective strategies are thought to represent promising approach to the therapy of MS. The therapeutic potential of glatiramer acetate (GA), a synthetic amino acid polymer composed of a mixture of L-glutamic acid, L-lysine, L-alanine, and L-tyrosine in defined proportions, in MS has been apparent for many years. GA has been shown to be effective in preventing and suppressing experimental allergic encephalomyelitis (EAE), the animal model of MS. GA has been, therefore, evaluated in several clinical studies and found to alter the natural history of relapsing-remitting (RR)MS by reducing the relapse rate and affecting disability. These findings were confirmed in open-label follow-up trials covering more than 10 years of treatment. The trials demonstrated sustained efficacy for GA in slowing the progression of disability. The clinical therapeutic effect of GA is consistent with the results of magnetic resonance imaging (MRI) findings from various clinical centers. At a daily standard dose of 20 mg, s.c., GA was generally well tolerated. The induction of GA-reactive T-helper 2-like regulatory suppressor cells is thought to be the main mechanism of the therapeutic action of this drug. In addition, it was recently shown that GA-reactive T cells produce neurotrophic factors (e.g., brain-derived neurotrophic factor [BDNF]) that protect neurons and axons in the area of injury.

Impaired Expression of Peripheral Blood Apoptotic-Related Gene Transcripts in Acute Multiple Sclerosis Relapse

Differential expression of apoptotic genes may influence the susceptibility of activated lymphocytes to expand and induce acute relapse and persistent inflammation in patients with relapsing-remitting multiple sclerosis (RRMS). The exact relationship between alterations in apoptotic-related gene expression and clinical disease activity has not been broadly evaluated. In this study we studied peripheral blood mononuclear cells (PBMCs) expression of pro- and antiapoptotic genes in RRMS patients during acute relapse in comparison to patients in remission. Using cDNA Affymetrix microarrays platform (U133A2 microarrays) we analyzed the gene expression profile of PBMC derived from 22 RRMS patients in acute relapse (15 females, mean age 34.6 +/- 1.8 years, disease duration 5.6 +/- 0.8 years) in comparison to 20 sex- and age-matched RRMS patients in remission. One thousand five hundred seventy-eight gene transcripts significantly differentiated acute multiple sclerosis (MS) relapse from remission. This characteristic gene expression signature was enriched by an apoptotic-related pathway. The 1578 gene transcripts that significantly differentiated acute relapse from remission were enriched by 55 apoptotic-related genes in that reflected different operating pathways during the acute phase of the disease. These genes mainly involved the caspase-dependent pathway and included overexpression of the negative regulator of FAS-induced apoptosis (TOSO) and the BCL2 antiapoptotic family members (BCL2, BCL2 AA) as well as downexpression of proapoptotic genes like BAX, apoptotic protease-activating factor 1 (APAF1) and caspases 1, 2, 8, 9. and 10. An additional group of antiapoptotic genes related to T cell receptor-mediated apoptosis was also found to be overexpressed in acute relapse and included TCR-binding CD3E antigen, antiapoptotic serine threonin kinase (AKT), and NF kappa B-associated genes like reticuloendotheliosis viral oncogene homolog A (RELA) and human T cell leukemia virus type I-binding protein (Tax1BP) known to inhibit tumor necrosis factor (TNF)-induced apoptosis. Our findings demonstrate impaired apoptotic mechanisms in peripheral lymphocytes from RRMS patients during acute relapse. This suggests that the inflammatory process in active disease is targeted by inhibition of proapoptotic and repression of antiapoptotic genes that allow prolonged abnormal immune responses.

Janus faces of microglia in multiple sclerosis

Multiple sclerosis (MS) is the most common cause of neurological disability in young adults. The disease is characterized by inflammatory reactions, demyelination and axonal loss in the brain, spinal cord and optic nerves. Microglia seem to play an important role in the inflammatory processes in MS, since they are found in actively demyelinating lesions. Their role in the differentiation of T cells could led to the expansion of inflammation and tissue destruction. However, microglia are also involved in the termination of an inflammatory response and produce protective factors. To be able to therapeutically manipulate microglia, their exact function in the onset and development of MS needs to be clarified. This review provides an overview of the functions of the most important microglia-associated molecules in MS, being CD40, B7-1 and B7-2, interferon-gamma, tumor necrosis factor-alpha, chemokines, prostanoids, and nitric oxide.

Simvastatin protects neurons from cytotoxicity by up-regulating Bcl-2 mRNA and protein

Statins are most commonly prescribed to reduce hypercholesterolemia; however, recent studies have shown that statins have additional benefits, including neuroprotection. Until now, the mechanism underlying statin-induced neuroprotection has been poorly understood. Recent in vivo studies from our lab reported the novel finding that simvastatin increased expression levels of a gene encoding for a major cell survival protein, bcl-2 [Johnson-Anuna et al., J. Pharmacol. Exp. Ther.312 (2005) 786]. The purpose of the present experiments was to determine if simvastatin could protect neurons from excitotoxicity by altering Bcl-2 levels. Neurons were pre-treated with simvastatin and challenged with a compound known to reduce Bcl-2 levels and induce cell death. Simvastatin pre-treatment resulted in a significant reduction in cytotoxicity (lactate dehydrogenase release and caspase 3 activation) following challenge compared with unchallenged neurons. In addition, chronic simvastatin treatment significantly increased Bcl-2 mRNA and protein levels while challenge resulted in a significant reduction in Bcl-2 protein abundance. G3139, an antisense oligonucleotide directed against Bcl-2, abolished the protective effects of simvastatin and eliminated simvastatin-induced up-regulation of Bcl-2 protein. These findings suggest that neuroprotection by simvastatin is dependent on the drug's previously unexplored and important effect of up-regulating Bcl-2.

Modulating apoptosis as a target for effective therapy

Alterations in cell proliferation and cell death are essential determinants in the pathogenesis and progression of several diseases such as cancer, neurodegenerative disorders or autoimmune diseases among others. Complex networks of regulatory factors determine whether cells proliferate or die. Recent progress in understanding the molecular changes offer the possibility of specifically targeting molecules and pathways to achieve more effective and rational therapies. Drugs that target molecules involved in apoptosis are used as treatment against several diseases. Candidates such as TNF death receptor family, caspase inhibitors, antagonists of the p53-MDM2 interaction, NF-kappaB and PI3K pathways and Bcl-2 family members have been targeted as cancer cell killing agents. Moreover, apoptosis of tumor cells can also be achieved by targeting the inhibitor of apoptosis proteins, IAPs, in addition to the classical antiproliferative approach. Disruption of STAT activation and interferon beta therapy have been used as a treatment to prevent the progression of some autoimmune diseases. In models of Parkinson's, Alzheimer's and amyotrophic lateral sclerosis, blocking of Par-4 expression or function, as well as caspase activation, prevents neuronal cell death. Finally, it has been shown that gene therapy may be an encouraging approach for treatment of neurodegenerative disorders.

Apoptosis of T cells in peripheral blood and cerebrospinal fluid is associated with disease activity of multiple sclerosis

Apoptotic elimination of pathogenic T cells is considered to be one of regulatory mechanisms in multiple sclerosis (MS). To explore the potential relationship between Fas-mediated apoptosis and the disease course of MS, we examined apoptosis, defined by annexin V (AV) binding, and Fas (CD95) expression in CD4+ and in CD8+ T cells in MS patients by using five-color flow cytometry. The percentage of AV+CD4+CD3+ cells and CD95+AV+CD4+CD3+ cells in peripheral blood and cerebrospinal fluid (CSF) were significantly decreased in active MS patients compared with inactive MS patients. A significantly lower proportion of CD95+AV+CD8+CD3+ cells in CSF was observed in active MS patients compared with inactive MS patients, but not in peripheral blood. These results indicate that the resistance of T cells to Fas-mediated apoptosis is involved in exacerbation of MS and/or that Fas-mediated apoptosis of T cells is associated with remission of MS.

Glatiramer acetate induces pro-apoptotic mechanisms involving Bcl-2, Bax and Cyt-c in peripheral lymphocytes from multiple sclerosis patients

Apoptotic deletion of autoreactive T-cells is defective in patients with multiple sclerosis (MS). Glatiramer acetate (GA) treatment seems to restore apoptosis of detrimental T-cells. We analyzed the mitochondria membrane pro- (Bax) and anti-apoptotic (Bcl- 2) and cytosolic pro-apoptotic (Cyt-c, APAF-1) proteins expression in peripheral lymphocytes from relapsing-remitting (RR) MS patients during GA treatment. Blood samples were collected from 8 healthy controls (HCs) and from 8 RR MS patients prior to and every three months during the 9 months of GA treatment. Peripheral blood mononuclear cells (PBMNCs) Bcl-2, Bax, Cyt-c and APAF-1 were quantified by western blot followed by densitometric scanning and Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios were calculated. T-cells were in vitro tested for oxygen consumption by a respirometric analysis. Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios in untreated MS patients were significantly (p < 0.05) lower than in HCs. Bax/Bcl-2 ratio increased (p = 0.03) and Cyt-c/Bcl-2 ratio showed a trend to increase during the 9 months of GA treatment in MS patients. A reduction of 58% and 59% in oxygen consumption by PBMNCs was evident after GA treatment in vitro or when GA treated patients' cells were compared with those from HCs, respectively. Our findings suggest that GA exerts a regulatory effect on peripheral T lymphocytes through pro-apoptosis mechanisms involving mitochondria and cytosolic proteins.

Microarray analysis identifies an aberrant expression of apoptosis and DNA damage-regulatory genes in multiple sclerosis

To clarify the molecular mechanisms underlying multiple sclerosis (MS)-promoting autoimmune process, we have investigated a comprehensive gene expression profile of T cell and non-T cell fractions of peripheral blood mononuclear cells (PBMC) isolated from 72 MS patients and 22 age- and sex-matched healthy control (CN) subjects by using a cDNA microarray. Among 1258 genes examined, 173 genes in T cells and 50 genes in non-T cells were expressed differentially between MS and CN groups. Downregulated genes greatly outnumbered upregulated genes in MS. More than 80% of the top 30 most significant genes were categorized into apoptosis signaling-related genes of both proapoptotic and antiapoptotic classes. They included upregulation in MS of orphan nuclear receptor Nurr1 (NR4A2), receptor-interacting serine/threonine kinase 2 (RIPK2), and silencer of death domains (SODD), and downregulation in MS of TNF-related apoptosis-inducing ligand (TRAIL), B-cell CLL/lymphoma 2 (BCL2), and death-associated protein 6 (DAXX). Furthermore, a set of the genes involved in DNA repair, replication, and chromatin remodeling was downregulated in MS. These results suggest that MS lymphocytes show a complex pattern of gene regulation that represents a counterbalance between promoting and preventing apoptosis and DNA damage of lymphocytes.

Is damage in central nervous system due to inflammation?

The aim of this work was to review the inflammatory factors involved in central nervous system (CNS) inflammation and the damage associated to their participation in an inflammatory disease of CNS, multiple sclerosis in humans and experimental allergic encephalomyelitis in the murine model. Inflammation has an important repairing function, nevertheless frequently in the CNS inflammation is the cause of damage and it does not fulfill this repairing function as it happens in other compartments of the body. The inflammatory response in the CNS involves the participation of different cellular types of the immune system (macrophages, mast cells, T and B lymphocytes, dendritic cells) and resident cells of the CNS (microglia, astrocytes, neurons), adhesion molecules, cytokines and chemokines among other proteic components. During neuroinflammation chemotaxis is an important event in the recruitment of cells to the CNS. The lymphocyte recruitment implies the presence of chemokines and chemokine receptors, the expression of adhesion molecules, the interaction between lymphocytes and the bloodbrain barrier (BBB) endothelium, and finally their passage through the BBB to arrive at the site of inflammation. If this process is not controlled, is prolonged, inflammation loses its repairing function and can be the cause of damage. Usually neuroinflammation has the tendency to decline to damage, which would explain most of the CNS pathologies.

Bax-ablation attenuates experimental autoimmune encephalomyelitis in mice

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system characterized by demyelination and axonal damage. Although the exact pathophysiology is unknown, apoptosis plays a crucial role. Here, we studied the role of the pro-apoptotic gene Bax in myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE), the animal model for MS. We demonstrate that the clinical signs were markedly reduced in the EAE Bax-deficient mice as compared to wild type (2.3 +/- 0.5 vs. 1.02 +/- 0.32, respectively, P < 0.05). Bax-deficient mice demonstrated less inflammatory infiltration and axonal damage, although they showed similar T-cell immune potency. In conclusion, ablation of the bax gene attenuates the severity of MOG-induced EAE and emphasizes the importance of apoptosis in the pathogenesis of EAE and MS.

JC virus induces nonapoptotic cell death of human central nervous system progenitor cell-derived astrocytes

JC virus (JCV), a human neurotropic polyomavirus, demonstrates a selective glial cell tropism that causes cell death through lytic infection. Whether these cells die via apoptosis or necrosis following infection with JCV remains unclear. To investigate the mechanism of virus-induced cell death, we used a human central nervous system progenitor-derived astrocyte cell culture model developed in our laboratory. Using in situ DNA hybridization, immunocytochemistry, electron microscopy, and an RNase protection assay, we observed that astrocytes support a progressive JCV infection, which eventually leads to nonapoptotic cell death. Infected astrocyte cell cultures showed no difference from noninfected cells in mRNA expression of the caspase family genes or in any ultrastructural features associated with apoptosis. Infected cells demonstrated striking necrotic features such as cytoplasmic vacuolization, watery cytoplasm, and dissolution of organelles. Furthermore, staining for caspase-3 and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling were not detected in infected astrocyte cultures. Our findings suggest that JCV-induced cell death of these progenitor cell-derived astrocytes does not utilize an apoptosis pathway but exhibits a pattern of cell destruction consistent with necrotic cell death.