Pre-existing central nervous system lesions negate cytokine requirements for regional experimental autoimmune encephalomyelitis development

A novel CNS-homing peptide for targeting neuroinflammatory lesions in experimental autoimmune encephalomyelitis

Using phage peptide library screening, we identified peptide-encoding phages that selectively home to the inflamed central nervous system (CNS) of mice with experimental autoimmune encephalomyelitis (EAE), a model of human multiple sclerosis (MS). A phage peptide display library encoding cyclic 9-amino-acid random peptides was first screened ex-vivo for binding to the CNS tissue of EAE mice, followed by in vivo screening in the diseased mice. Phage insert sequences that were present at a higher frequency in the CNS of EAE mice than in the normal (control) mice were identified by DNA sequencing. One of the phages selected in this manner, denoted as MS-1, was shown to selectively recognize CNS tissue in EAE mice. Individually cloned phages with this insert preferentially homed to EAE CNS after an intravenous injection. Similarly, systemically-administered fluorescence-labeled synthetic MS-1 peptide showed selective accumulation in the spinal cord of EAE mice. We suggest that peptide MS-1 might be useful for targeted drug delivery to CNS in EAE/MS.

The miRNA Expression Profile of Experimental Autoimmune Encephalomyelitis Reveals Novel Potential Disease Biomarkers

Multiple sclerosis (MS) is a debilitating autoimmune disease affecting over 2.3 million people worldwide, and it is characterized by inflammation and demyelination of nerve cells. The currently available biomarkers for the diagnosis and management of MS have inherent limitations, therefore, additional new biomarkers are needed. We studied the microRNA (miRNA) profile of splenocytes of mice having experimental autoimmune encephalomyelitis (EAE), a model of human MS. A miRNA-microarray analysis revealed increased expression of nine miRNAs (let-7e, miR-23b, miR-31, miR-99b, miR-125a, miR-146b, miR-155, miR-193b, and miR-221) following EAE development. Interestingly, serum levels of miR-99b, miR-125a, and miR-146b were significantly higher in EAE mice compared to normal mice. Bioinformatics analysis revealed the experimentally validated as well as predicted gene targets of specific miRNAs that are important for disease progression in MS. Specifically, we observed inverse correlation in the levels of miR-99b versus LIF, and between miR-125a versus BDNF and LIF. Our results suggest that above-mentioned miRNAs may play a crucial role in the pathogenesis of MS, and that miR-99b, miR-125a, and miR-146b in particular may serve as useful biomarkers for disease activity.

Experimental autoimmune encephalomyelitis (EAE) up-regulates the mitochondrial activity and manganese superoxide dismutase (MnSOD) in the mouse renal cortex

Increases of the activity of mitochondrial electron transport chain generally lead to increases of production of ATP and reactive oxygen species (ROS) as by-products. MnSOD is the first line of defense against the stress induced by mitochondrial ROS. Our previous studies demonstrated that EAE progression increased Na,K-ATPase activity in the mouse kidney cortex. Since mitochondria are the major source of ATP, our present studies were sought to determine whether EAE progression increased mitochondrial activity. We found that severe EAE increased mitochondrial complex II and IV activities without significantly affecting complex I activity with corresponding increases of ROS in the isolated mitochondria and native kidney cortex. Severe EAE augmented both cytosolic and mitochondrial MnSOD protein levels and activities and decreased the specific activity of mitochondrial MnSOD when the total mitochondrial MnSOD activity was normalized to the protein level. Using HEK293 cells as a model free of interference from immune reactions, we found that activation of Na,K-ATPase by monensin for 24 hours increased complex II activity, mitochondrial ROS and MnSOD protein abundance, and decreased the specific activity of the mitochondrial MnSOD. Inhibition of Na,K-ATPase by ouabain or catalase attenuated the effects of monensin on the mitochondrial complex II activity, ROS, MnSOD protein level and specific activity. Kockdown of MnSOD by RNAi reduced the mitochondrial ability to generate ATP. In conclusion, EAE increases mitochondrial activity possibly to meet the energy demand from increased Na,K-ATPase activity. EAE increases mitochondrial MnSOD protein abundance to compensate for the loss of the specific activity of the enzyme, thus minimizing the harmful effects of ROS.

Progression of experimental autoimmune encephalomyelitis is associated with up-regulation of major sodium transporters in the mouse kidney cortex under a normal salt diet

Recent demonstrations of exacerbation of experimental autoimmune encephalomyelitis (EAE) by high salt diets prompted us to study whether EAE stimulated Na absorption by the renal cortex, a primary regulatory site for Na balance, even under a normal NaCl diet. We found that as EAE progressed from mild to severe symptoms, there were parallel increases in the protein abundance of NHE3 and αENaC and the Na,K-ATPase activity with an affiliated elevation of its β1-subunit protein. These effects are associated with increases in the protein levels of the well-known regulators SGK1 and scaffold NHERF2, and phosphorylation of ERK1/2. These effects of EAE could not be explained by reduction in water or food intake. We conclude that EAE progression is associated with up-regulation of major Na transporters, which is most likely driven by increased expression of SGK1 and NHERF2 and activation of ERK1/2. These data suggest that EAE progression increases Na absorption by the renal cortex.

Interferon gamma in autoimmunity: A complicated player on a complex stage

Early views of autoimmune disease cast IFNγ as a prototypic pro-inflammatory factor. It is now clear that IFNγ is capable of both pro- and anti-inflammatory activities with the functional outcome dependent on the physiological and pathological setting examined. Here, the major immune modulatory activities of IFNγ are reviewed and current evidence for the impact of IFNγ on pathology and regulation of several autoimmune diseases and disease models is summarized.

Cancer genomic research at the crossroads: realizing the changing genetic landscape as intratumoral spatial and temporal heterogeneity becomes a confounding factor

The US National Cancer Institute (NCI) and the National Human Genome Research Institute (NHGRI) created the Cancer Genome Atlas (TCGA) Project in 2006. The TCGA’s goal was to sequence the genomes of 10,000 tumors to identify common genetic changes among different types of tumors for developing genetic-based treatments. TCGA offered great potential for cancer patients, but in reality has little impact on clinical applications. Recent reports place the past TCGA approach of testing a small tumor mass at a single time-point at a crossroads. This crossroads presents us with the conundrum of whether we should sequence more tumors or obtain multiple biopsies from each individual tumor at different time points. Sequencing more tumors with the past TCGA approach of single time-point sampling can neither capture the heterogeneity between different parts of the same tumor nor catch the heterogeneity that occurs as a function of time, error rates, and random drift. Obtaining multiple biopsies from each individual tumor presents multiple logistical and financial challenges. Here, we review current literature and rethink the utility and application of the TCGA approach. We discuss that the TCGA-led catalogue may provide insights into studying the functional significance of oncogenic genes in reference to non-cancer genetic background. Different methods to enhance identifying cancer targets, such as single cell technology, real time imaging of cancer cells with a biological global positioning system, and cross-referencing big data sets, are offered as ways to address sampling discrepancies in the face of tumor heterogeneity. We predict that TCGA landmarks may prove far more useful for cancer prevention than for cancer diagnosis and treatment when considering the effect of non-cancer genes and the normal genetic background on tumor microenvironment. Cancer prevention can be better realized once we understand how therapy affects the genetic makeup of cancer over time in a clinical setting. This may help create novel therapies for gene mutations that arise during a tumor’s evolution from the selection pressure of treatment.