Suppression of inflammatory responses during myelin oligodendrocyte glycoprotein-induced experimental autoimmune encephalomyelitis is regulated by AKT3 signaling

Monkeypox Virus Crosstalk with HIV: An Integrated Skin Transcriptome and Machine Learning Study

The emergence of the monkeypox virus (MPXV) outbreak presents a formidable challenge to human health. Emerging evidence suggests that individuals with HIV have been disproportionately affected by MPXV, with adverse clinical outcomes and higher mortality rates. However, the shared molecular mechanisms underlying MPXV and HIV remain elusive. We identified differentially expressed genes (DEGs) from two public data sets, GSE219036 and GSE184320, and extracted common DEGs between MPXV and HIV. We further performed gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), protein-protein interactions (PPI), candidate drug assessment, and immune correlation of hub genes analysis. We validated the key biomarkers using multiple machine learning (ML) methods including random forest (RF), t-distributed stochastic neighbor embedding (tSNE), and uniform manifold approximation and projection (UMAP). A total of 59 common DEGs were identified between MPXV and HIV. Our functional analysis highlighted multiple pathways, including the ERK cascade, NF-κB signaling, and various immune responses, playing a collaborative role in the progression of both diseases. The PPI and gene co-expression networks were constructed, and five key genes with significant immune correlations were identified and validated by multiple ML models, including SPRED1, SPHK1, ATF3, AKT3, and AKT1S1. Our study emphasizes the common pathogenesis of HIV and MPXV and highlights the pivotal genes and shared pathways, providing new opportunities for evidence-based management strategies in HIV patients co-infected with MPXV.

Akt isoforms in the immune system

Akt is a PI3K-activated serine-threonine kinase that exists in three distinct isoforms. Akt's expression in most immune cells, either at baseline or upon activation, reflects its importance in the immune system. While Akt is most highly expressed in innate immune cells, it plays crucial roles in both innate and adaptive immune cell development and/or effector functions. In this review, we explore what's known about the role of Akt in innate and adaptive immune cells. Wherever possible, we discuss the overlapping and distinct role of the three Akt isoforms, namely Akt1, Akt2, and Akt3, in immune cells.

Transcriptome profiling based on larvae at different time points after hatching provides a core set of gene resource for understanding the immune response mechanisms of the egg-protecting behavior against Vibrio anguillarum infection in Amphioctopus fangsiao

Mollusks have recently received increasing attention because of their unique immune systems. Mollusks such as Amphioctopus fangsiao are economically important cephalopods, and the effects of their egg-protecting behavior on the larval immune response are unclear. Meanwhile, little research has been done on the resistance response of cephalopod larvae infected with pathogenic bacteria such as Vibrio anguillarum. In this study, V. anguillarum was used to infect the primary hatching A. fangsiao larvae under different egg-protecting behaviors for 24 h, and a total of 7156 differentially expressed genes (DEGs) were identified at four time points after hatching based on transcriptome analysis. GO and KEGG enrichment analyses showed that multiple immune-related GO terms and KEGG signaling pathways were enriched. Protein-protein interaction networks (PPI networks) were used to search functional relationships between immune-related DEGs. Finally, 20 hub genes related to multiple gene functions or involved in multiple signaling pathways were identified, and their accuracy was verified using quantitative RT-PCR. PPI networks were first used to study the effects A. fangsiao larvae after infection with V. anguillarum under different egg-protecting behaviors. The results provide significant genetic resources for exploring invertebrate larval immune processes. The data lays a foundation for further study the immune response mechanisms for invertebrates after infection.

Transcriptome profiling based on protein-protein interaction networks provides a set of core genes for understanding the immune response mechanisms of the egg-protecting behavior in Octopus ocellatus

Protection via of the immune system is indispensable to the life of organisms. Within an immune network, problems with a given link will affect the normal life activities of the organism. Octopus ocellatus is cephalopod widely distributed throughout the world's oceans. Because of its unique nervous system and locomotive organs, research on this species has gradually increased in recent years. Many immune response mechanisms associated with behaviors of O. ocellatus are still unclear. Moreover, as a factor affecting the normal growth of O. ocellatus, egg protection has rarely been considered in previous behavioral studies. In this study, we analyzed the transcriptome profile of gene expression in O. ocellatus larvae, and identified 5936 differentially expressed genes (DEGs). GO and KEGG enrichment analyses were used to search for immune-related DEGs. Protein-protein interaction networks were constructed to examine the interactions between immune-related genes. Fifteen hub genes involved in multiple KEGG signaling pathways or with multiple protein-protein interaction relationships were obtained and verified by quantitative RT-PCR. We first studied the effects of egg protection on the immunity of O. ocellatus larvae by means of protein-protein interaction networks, and the results provide valuable genetic resources for understanding the immunity of invertebrate larvae. The data serve as a foundation for further research on the egg-protecting behavior of invertebrates.

Oligodendrocyte-Specific Deletion of FGFR1 Reduces Cerebellar Inflammation and Neurodegeneration in MOG35-55-Induced EAE

Multiple sclerosis (MS) is a chronic inflammatory and degenerative disease of the central nervous system (CNS). MS commonly affects the cerebellum causing acute and chronic symptoms. Cerebellar signs significantly contribute to clinical disability, and symptoms such as tremor, ataxia, and dysarthria are difficult to treat. Fibroblast growth factors (FGFs) and their receptors (FGFRs) are involved in demyelinating pathologies such as MS. In autopsy tissue from patients with MS, increased expression of FGF1, FGF2, FGF9, and FGFR1 was found in lesion areas. Recent research using mouse models has focused on regions such as the spinal cord, and data on the expression of FGF/FGFR in the cerebellum are not available. In recent EAE studies, we detected that oligodendrocyte-specific deletion of FGFRs results in a milder disease course, less cellular infiltrates, and reduced neurodegeneration in the spinal cord. The objective of this study was to characterize the role of FGFR1 in oligodendrocytes in the cerebellum. Conditional deletion of FGFR1 in oligodendrocytes (Fgfr1^ind−/−) was achieved by tamoxifen application, EAE was induced using the MOG_35-55 peptide. The cerebellum was analyzed by histology, immunohistochemistry, and western blot. At day 62 p.i., Fgfr1^ind−/− mice showed less myelin and axonal degeneration compared to FGFR1-competent mice. Infiltration of CD3(+) T cells, Mac3(+) cells, B220(+) B cells and IgG(+) plasma cells in cerebellar white matter lesions (WML) was less in Fgfr1^ind−/−mice. There were no effects on the number of OPC or mature oligodendrocytes in white matter lesion (WML). Expression of FGF2 and FGF9 associated with less myelin and axonal degeneration, and of the pro-inflammatory cytokines IL-1β, IL-6, and CD200 was downregulated in Fgfr1^ind−/− mice. The FGF/FGFR signaling protein pAkt, BDNF, and TrkB were increased in Fgfr1^ind−/− mice. These data suggest that cell-specific deletion of FGFR1 in oligodendrocytes has anti-inflammatory and neuroprotective effects in the cerebellum in the EAE disease model of MS.

IL-17 Inhibits Oligodendrocyte Progenitor Cell Proliferation and Differentiation by Increasing K+ Channel Kv1.3

Interleukin 17 (IL-17) is a signature cytokine of Th17 cells. IL-17 level is significantly increased in inflammatory conditions of the CNS, including but not limited to post-stroke and multiple sclerosis. IL-17 has been detected direct toxicity on oligodendrocyte (Ol) lineage cells and inhibition on oligodendrocyte progenitor cell (OPC) differentiation, and thus promotes myelin damage. The cellular mechanism of IL-17 in CNS inflammatory diseases remains obscure. Voltage-gated K⁺ (Kv) channel 1.3 is the predominant Kv channel in Ol and potentially involved in Ol function and cell cycle regulation. Kv1.3 of T cells involves in immunomodulation of inflammatory progression, but the role of Ol Kv1.3 in inflammation-related pathogenesis has not been fully investigated. We hypothesized that IL-17 induces myelin injury through Kv1.3 activation. To test the hypothesis, we studied the involvement of OPC/Ol Kv1.3 in IL-17-induced Ol/myelin injury in vitro and in vivo. Kv1.3 currents and channel expression gradually decreased during the OPC development. Application of IL-17 to OPC culture increased Kv1.3 expression, leading to a decrease of AKT activation, inhibition of proliferation and myelin basic protein reduction, which were prevented by a specific Kv1.3 blocker 5-(4-phenoxybutoxy) psoralen. IL-17-caused myelin injury was validated in LPC-induced demyelination mouse model, particularly in corpus callosum, which was also mitigated by aforementioned Kv1.3 antagonist. IL-17 altered Kv1.3 expression and resultant inhibitory effects on OPC proliferation and differentiation may by interrupting AKT phosphorylating activation. Taken together, our results suggested that IL-17 impairs remyelination and promotes myelin damage by Kv1.3-mediated Ol/myelin injury. Thus, blockade of Kv1.3 as a potential therapeutic strategy for inflammatory CNS disease may partially attribute to the direct protection on OPC proliferation and differentiation other than immunomodulation.

Immunohistological Examination of AKT Isoforms in the Brain: Cell-Type Specificity That May Underlie AKT's Role in Complex Brain Disorders and Neurological Disease

Protein kinase B (PKB/AKT) is a central kinase involved in many neurobiological processes. AKT is expressed in the brain as three isoforms, AKT1, AKT2, and AKT3. Previous studies suggest isoform-specific roles in neural function, but very few studies have examined AKT isoform expression at the cellular level. In this study, we use a combination of histology, immunostaining, and genetics to characterize cell-type-specific expression of AKT isoforms in human and mouse brains. In mice, we find that AKT1 is the most broadly expressed isoform, with expression in excitatory neurons and the sole detectable AKT isoform in gamma-aminobutyric acid ergic interneurons and microglia. By contrast, we find that AKT2 is the sole isoform expressed in astroglia and is not detected in other neural cell types. We find that AKT3 is expressed in excitatory neurons with AKT1 but shows greater expression levels in dendritic compartments than AKT1. We extend our analysis to human brain tissues and find similar results. Using genetic deletion approaches, we also find that the cellular determinants restricting AKT isoform expression to specific cell types remain intact under Akt deficiency conditions. Because AKT signaling is linked to numerous neurological disorders, a greater understanding of cell-specific isoform expression could improve treatment strategies involving AKT.

Effects of FGFR Tyrosine Kinase Inhibition in OLN-93 Oligodendrocytes

Fibroblast growth factor (FGF) signaling is involved in the pathogenesis of multiple sclerosis (MS). Data from neuropathology studies suggest that FGF signaling contributes to the failure of remyelination in MS. In MOG_35–55-induced EAE, oligodendrocyte-specific deletion of FGFR1 and FGFR2 resulted in a less severe disease course, reduced inflammation, myelin and axon degeneration and changed FGF/FGFR and BDNF/TrkB signaling. Since signaling cascades in oligodendrocytes could not be investigated in the EAE studies, we here aimed to characterize FGFR-dependent oligodendrocyte-specific signaling in vitro. FGFR inhibition was achieved by application of the multi-kinase-inhibitor dovitinib and the FGFR1/2/3-inhibitor AZD4547. Both substances are potent inhibitors of FGF signaling; they are effective in experimental tumor models and patients with malignancies. Effects of FGFR inhibition in oligodendrocytes were studied by immunofluorescence microscopy, protein and gene analyses. Application of the tyrosine kinase inhibitors reduced FGFR1, phosphorylated ERK and Akt expression, and it enhanced BDNF and TrkB expression. Furthermore, the myelin proteins CNPase and PLP were upregulated by FGFR inhibition. In summary, inhibition of FGFR signaling in oligodendrocytes can be achieved by application of tyrosine kinase inhibitors. Decreased phosphorylation of ERK and Akt is associated with an upregulation of BDNF/TrkB signaling, which may be responsible for the increased production of myelin proteins. Furthermore, these data suggest that application of FGFR inhibitors may have the potential to promote remyelination in the CNS.

Population Genomics Reveals Incipient Speciation, Introgression, and Adaptation in the African Mona Monkey (Cercopithecus mona)

Guenons (tribe Cercopithecini) are the most widely distributed nonhuman primate in the tropical forest belt of Africa and show considerable phenotypic, taxonomic, and ecological diversity. However, genomic information for most species within this group is still lacking. Here, we present a high-quality de novo genome (total 2.90 Gb, contig N50 equal to 22.7 Mb) of the mona monkey (Cercopithecus mona), together with genome resequencing data of 13 individuals sampled across Nigeria. Our results showed differentiation between populations from East and West of the Niger River ∼84 ka and potential ancient introgression in the East population from other mona group species. The PTPRK, FRAS1, BNC2, and EDN3 genes related to pigmentation displayed signals of introgression in the East population. Genomic scans suggest that immunity genes such as AKT3 and IL13 (possibly involved in simian immunodeficiency virus defense), and G6PD, a gene involved in malaria resistance, are under positive natural selection. Our study gives insights into differentiation, natural selection, and introgression in guenons.

Oligodendrocyte-specific deletion of FGFR2 ameliorates MOG35-55 -induced EAE through ERK and Akt signalling

Fibroblast growth factors (FGFs) and their receptors (FGFRs) are involved in demyelinating pathologies including multiple sclerosis (MS). In our recent study, oligodendrocyte‐specific deletion of FGFR1 resulted in a milder disease course, less inflammation, reduced myelin and axon damage in EAE. The objective of this study was to elucidate the role of oligodendroglial FGFR2 in MOG_35‐55‐induced EAE. Oligodendrocyte‐specific knockout of FGFR2 (Fgfr2^ind−/−) was achieved by application of tamoxifen; EAE was induced using the MOG_35‐55 peptide. EAE symptoms were monitored over 62 days. Spinal cord tissue was analysed by histology, immunohistochemistry and western blot. Fgfr2^ind−/− mice revealed a milder disease course, less myelin damage and enhanced axonal density. The number of oligodendrocytes was not affected in demyelinated areas. However, protein expression of FGFR2, FGF2 and FGF9 was downregulated in Fgfr2^ind−/− mice. FGF/FGFR dependent signalling proteins were differentially regulated; pAkt was upregulated and pERK was downregulated in Fgfr2^ind−/− mice. The number of CD3(+) T cells, Mac3(+) cells and B220(+) B cells was less in demyelinated lesions of Fgfr2^ind−/− mice. Furthermore, expression of IL‐1β, TNF‐α and CD200 was less in Fgfr2^ind−/− mice than controls. Fgfr2^ind−/− mice showed an upregulation of PLP and downregulation of the remyelination inhibitors SEMA3A and TGF‐β expression. These data suggest that cell‐specific deletion of FGFR2 in oligodendrocytes has anti‐inflammatory and neuroprotective effects accompanied by changes in FGF/FGFR dependent signalling, inflammatory cytokines and expression of remyelination inhibitors. Thus, FGFRs in oligodendrocytes may represent potential targets for the treatment of inflammatory and demyelinating diseases including MS.

Anti-Axl antibody treatment reduces the severity of experimental autoimmune encephalomyelitis

BACKGROUND

Multiple sclerosis is an immune-mediated disease of the central nervous system (CNS) characterized by inflammation, oligodendrocytes loss, demyelination, and damaged axons. Tyro3, Axl, and MerTK belong to a family of receptor tyrosine kinases that regulate innate immune responses and CNS homeostasis. During experimental autoimmune encephalomyelitis (EAE), the mRNA expression of MerTK, Gas6, and Axl significantly increase, whereas Tyro3 and ProS1 remain unchanged. We have shown that Gas6 is neuroprotective during EAE, and since Gas6 activation of Axl may be necessary for conferring neuroprotection, we sought to determine whether α-Axl or α-MerTK antibodies, shown by others to activate their respective receptors in vivo, could effectively reduce inflammation and neurodegeneration.

METHODS

Mice received either α-Axl, α-MerTK, IgG isotype control, or PBS before the onset of EAE symptoms. EAE clinical course, axonal damage, demyelination, cytokine production, and immune cell activation in the CNS were used to determine the severity of EAE.

RESULTS

α-Axl antibody treatment significantly decreased the EAE clinical indices of female mice during chronic EAE and of male mice during both acute and chronic phases. The number of days mice were severely paralyzed also significantly decreased with α-Axl treatment. Inflammatory macrophages/microglia and the extent of demyelination significantly decreased in the spinal cords of α-Axl-treated mice during chronic EAE, with no differences in the production of pro-inflammatory cytokines. α-MerTK antibody did not influence EAE induction or progression.

CONCLUSION

Our data suggests that the beneficial effect of Gas6/Axl signaling observed in mice administered with Gas6 can be partially preserved by administering an activating α-Axl antibody, but not α-MerTK.

Adaptive Molecular Evolution of AKT3 Gene for Positive Diversifying Selection in Mammals

The V-Akt Murine Thymoma Viral Oncogene Homolog 3 (AKT3) gene is of the serine/threonine-protein kinase family and influences the production of milk fats and cholesterol by acting on the sterol administrative area restricting protein (SREBP). The AKT3 gene is highly preserved in animals, and during lactation in cattle, its expression increases. The AKT3 gene is expressed in the digestive system, mammary gland, and immune cells. A phylogenetic investigation was performed to clarify the evolutionary role of AKT3, by maximum probability. The AKT3 gene sequence data of various mammalian species was evident even with animals undergoing breeding selection. From 39 mammalian species studied, there was a signal of positive diversifying selection with Hominidae at 13Q, 16G, 23R, 24P, 121P, 294K, 327V, 376L, 397K, 445T, and 471F among other codon sites of the AKT3 gene. These sites were codes for amino acids such as arginine, proline, lysine, and leucine indicating major roles for the function of immunological proteins, and in particular, the study highlighted the importance of changes in gene expression of AKT3 on immunity.

Prolonged inflammation leads to ongoing damage after spinal cord injury

The pathogenesis of spinal cord injury (SCI) remains poorly understood and treatment remains limited. Emerging evidence indicates that post-SCI inflammation is severe but the role of reactive astrogliosis not well understood given its implication in ongoing inflammation as damaging or neuroprotective. We have completed an extensive systematic study with MRI, histopathology, proteomics and ELISA analyses designed to further define the severe protracted and damaging inflammation after SCI in a rat model. We have identified 3 distinct phases of SCI: acute (first 2 days), inflammatory (starting day 3) and resolution (>3 months) in 16 weeks follow up. Actively phagocytizing, CD68+/CD163- macrophages infiltrate myelin-rich necrotic areas converting them into cavities of injury (COI) when deep in the spinal cord. Alternatively, superficial SCI areas are infiltrated by granulomatous tissue, or arachnoiditis where glial cells are obliterated. In the COI, CD68+/CD163- macrophage numbers reach a maximum in the first 4 weeks and then decline. Myelin phagocytosis is present at 16 weeks indicating ongoing inflammatory damage. The COI and arachnoiditis are defined by a wall of progressively hypertrophied astrocytes. MR imaging indicates persistent spinal cord edema that is linked to the severity of inflammation. Microhemorrhages in the spinal cord around the lesion are eliminated, presumably by reactive astrocytes within the first week post-injury. Acutely increased levels of TNF-alpha, IL-1beta, IFN-gamma and other pro-inflammatory cytokines, chemokines and proteases decrease and anti-inflammatory cytokines increase in later phases. In this study we elucidated a number of fundamental mechanisms in pathogenesis of SCI and have demonstrated a close association between progressive astrogliosis and reduction in the severity of inflammation.

Akt3-Mediated Protection Against Inflammatory Demyelinating Disease

Akt is a serine/threonine protein kinase that plays a major role in regulating multiple cellular processes. While the isoforms Akt1 and Akt2 are involved in apoptosis and insulin signaling, respectively, the role for Akt3 remains uncertain. Akt3 is predominantly expressed in the brain, and total deletion of Akt3 in mice results in a reduction in brain size and neurodegeneration following injury. Previously, we found that Akt3-/- mice have a significantly worse clinical course during myelin-oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE), an animal model in which autoreactive immune cells enter the CNS, resulting in inflammation, demyelination, and axonal injury. Spinal cords of Akt3-/- mice are severely demyelinated and have increased inflammation compared to WT, suggesting a neuroprotective role for Akt3 during EAE. To specifically address the role of Akt3 in neuroinflammation and maintaining neuronal integrity, we used several mouse strains with different manipulations to Akt3. During EAE, Akt3 Nmf350 mice (with enhanced Akt3 kinase activity) had lower clinical scores, a lag in disease onset, a delay in the influx of inflammatory cells into the CNS, and less axonal damage compared to WT mice. A significant increased efficiency of differentiation toward FOXP3 expressing iTregs was also observed in Akt3 Nmf350 mice relative to WT. Mice with a conditional deletion of Akt3 in CD4+ T-cells had an earlier onset of EAE symptoms, increased inflammation in the spinal cord and brain, and had fewer FOXP3+ cells and FOXP3 mRNA expression. No difference in EAE outcome was observed when Akt3 expression was deleted in neurons (Syn1-CKO). These results indicate that Akt3 signaling in T-cells and not neurons is necessary for maintaining CNS integrity during an inflammatory demyelinating disease.

Akt-1 and Akt-2 Differentially Regulate the Development of Experimental Autoimmune Encephalomyelitis by Controlling Proliferation of Thymus-Derived Regulatory T Cells

Akt isoforms play key roles in multiple cellular processes; however, the roles of Akt-1 and Akt-2 isoforms in the development of T cell-mediated autoimmunity are poorly defined. In this study, we showed that Akt1^-/- mice develop ameliorated experimental autoimmune encephalomyelitis (EAE), a mouse model of multiple sclerosis, whereas Akt2^-/- mice develop exacerbated EAE, compared with wild-type mice. At the cellular level, Akt-1 appears to inhibit proliferation of thymus-derived regulatory T cells (tTregs), which facilitates Ag-specific Th1/Th17 responses. In a sharp contrast to Akt-1, Akt-2 potentiates tTreg proliferation in vitro and in vivo and suppresses Ag-specific Th1/Th17 responses. Furthermore, treating mice with established EAE with a specific Akt-1 inhibitor suppressed disease progression. Our data demonstrate that Akt-1 and Akt-2 differentially regulate the susceptibility of mice to EAE by controlling tTreg proliferation. Our data also indicate that targeting Akt-1 is a potential therapeutic approach for multiple sclerosis in humans.

Comparative Analysis of V-Akt Murine Thymoma Viral Oncogene Homolog 3 (AKT3) Gene between Cow and Buffalo Reveals Substantial Differences for Mastitis

AKT3 gene is a constituent of the serine/threonine protein kinase family and plays a crucial role in synthesis of milk fats and cholesterol by regulating activity of the sterol regulatory element binding protein (SREBP). AKT3 is highly conserved in mammals and its expression levels during the lactation periods of cattle are markedly increased. AKT3 is highly expressed in the intestine followed by mammary gland and it is also expressed in immune cells. It is involved in the TLR pathways as effectively as proinflammatory cytokines. The aims of this study were to investigate the sequences differences between buffalo and cow. Our results showed that there were substantial differences between buffalo and cow in some exons and noteworthy differences of the gene size in different regions. We also identified the important consensus sequence motifs, variation in 2000 upstream of ATG, substantial difference in the "3'UTR" region, and miRNA association in the buffalo sequences compared with the cow. In addition, genetic analyses, such as gene structure, phylogenetic tree, position of different motifs, and functional domains, were performed to establish their correlation with other species. This may indicate that a buffalo breed has potential resistance to disease, environment changes, and airborne microorganisms and some good production and reproductive traits.

miR-130a and miR-212 Disrupt the Intestinal Epithelial Barrier through Modulation of PPARγ and Occludin Expression in Chronic Simian Immunodeficiency Virus-Infected Rhesus Macaques

Intestinal epithelial barrier dysfunction is a well-known sequela of HIV/SIV infection that persists despite antiretroviral therapy. Although inflammation is a triggering factor, the underlying molecular mechanisms remain unknown. Emerging evidence suggests that epithelial barrier function is epigenetically regulated by inflammation-induced microRNAs (miRNAs). Accordingly, we profiled and characterized miRNA/mRNA expression exclusively in colonic epithelium and identified 46 differentially expressed miRNAs (20 upregulated and 26 downregulated) in chronically SIV-infected rhesus macaques (Macaca mulatta). We bioinformatically crossed the predicted miRNA targets to transcriptomic data and characterized miR-130a and miR-212 as both were predicted to interact with critical epithelial barrier-associated genes. Next, we characterized peroxisome proliferator-activated receptor γ (PPARγ) and occludin (OCLN), predicted targets of miR-130a and miR-212, respectively, as their downregulation has been strongly linked to epithelial barrier disruption and dysbiosis. Immunofluorescence, luciferase reporter, and overexpression studies confirmed the ability of miR-130a and miR-212 to decrease protein expression of PPARγ and OCLN, respectively, and reduce transepithelial electrical resistance. Because Δ-9-tetrahydrocannabinol exerted protective effects in the intestine in our previous studies, we successfully used it to reverse miR-130a- and miR-212-mediated reduction in transepithelial electrical resistance. Finally, ex vivo Δ-9-tetrahydrocannabinol treatment of colon tissue from chronically SIV-infected rhesus macaques significantly increased PPARγ expression. Our findings suggest that dysregulated miR-130a and miR-212 expression in colonic epithelium during chronic HIV/SIV infection can facilitate epithelial barrier disruption by downregulating OCLN and PPARγ expression. Most importantly, our results highlight the beneficial effects of cannabinoids on epithelial barrier function in not just HIV/SIV but potentially other chronic intestinal inflammatory diseases.

RNS60 exerts therapeutic effects in the SOD1 ALS mouse model through protective glia and peripheral nerve rescue

BACKGROUND

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects the motor neuromuscular system leading to complete paralysis and premature death. The multifactorial nature of ALS that involves both cell-autonomous and non-cell-autonomous processes contributes to the lack of effective therapies, usually targeted to a single pathogenic mechanism. RNS60, an experimental drug containing oxygenated nanobubbles generated by modified Taylor-Couette-Poiseuille flow with elevated oxygen pressure, has shown anti-inflammatory and neuroprotective properties in different experimental paradigms. Since RNS60 interferes with multiple cellular mechanisms known to be involved in ALS pathology, we evaluated its effect in in vitro and in vivo models of ALS.

METHODS

Co-cultures of primary microglia/spinal neurons exposed to LPS and astrocytes/spinal neurons from SOD1^G93A mice were used to examine the effect of RNS60 or normal saline (NS) on the selective motor neuron degeneration. Transgenic SOD1^G93A mice were treated with RNS60 or NS (300 μl/mouse intraperitoneally every other day) starting at the disease onset and examined for disease progression as well as pathological and biochemical alterations.

RESULTS

RNS60 protected motor neurons in in vitro paradigms and slowed the disease progression of C57BL/6-SOD1^G93A mice through a significant protection of spinal motor neurons and neuromuscular junctions. This was mediated by the (i) activation of an antioxidant response and generation of an anti-inflammatory environment in the spinal cord; (ii) activation of the PI3K-Akt pro-survival pathway in the spinal cord and sciatic nerves; (iii) reduced demyelination of the sciatic nerves; and (iv) elevation of peripheral CD4+/Foxp3+ T regulatory cell numbers. RNS60 did not show the same effects in 129Sv-SOD1^G93A mice, which are unable to activate a protective immune response.

CONCLUSION

RNS60 demonstrated significant therapeutic efficacy in C57BL/6-SOD1^G93A mice by virtue of its effects on multiple disease mechanisms in motor neurons, glial cells, and peripheral immune cells. These findings, together with the excellent clinical safety profile, make RNS60 a promising candidate for ALS therapy and support further studies to unravel its molecular mechanism of action. In addition, the differences in efficacy of RNS60 in SOD1^G93A mice of different strains may be relevant for identifying potential markers to predict efficacy in clinical trials.

Molecular Mechanisms Modulating the Phenotype of Macrophages and Microglia

Macrophages and microglia play crucial roles during central nervous system development, homeostasis and acute events such as infection or injury. The diverse functions of tissue macrophages and microglia are mirrored by equally diverse phenotypes. A model of inflammatory/M1 versus a resolution phase/M2 macrophages has been widely used. However, the complexity of macrophage function can only be achieved by the existence of varied, plastic and tridimensional macrophage phenotypes. Understanding how tissue macrophages integrate environmental signals via molecular programs to define pathogen/injury inflammatory responses provides an opportunity to better understand the multilayered nature of macrophages, as well as target and modulate cellular programs to control excessive inflammation. This is particularly important in MS and other neuroinflammatory diseases, where chronic inflammatory macrophage and microglial responses may contribute to pathology. Here, we perform a comprehensive review of our current understanding of how molecular pathways modulate tissue macrophage phenotype, covering both classic pathways and the emerging role of microRNAs, receptor-tyrosine kinases and metabolism in macrophage phenotype. In addition, we discuss pathway parallels in microglia, novel markers helpful in the identification of peripheral macrophages versus microglia and markers linked to their phenotype.

Akt Signaling Pathway in Macrophage Activation and M1/M2 Polarization

Macrophages become activated initiating innate immune responses. Depending on the signals, macrophages obtain an array of activation phenotypes, described by the broad terms of M1 or M2 phenotype. The PI3K/Akt/mTOR pathway mediates signals from multiple receptors including insulin receptors, pathogen-associated molecular pattern receptors, cytokine receptors, adipokine receptors, and hormones. As a result, the Akt pathway converges inflammatory and metabolic signals to regulate macrophage responses modulating their activation phenotype. Akt is a family of three serine-threonine kinases, Akt1, Akt2, and Akt3. Generation of mice lacking individual Akt, PI3K, or mTOR isoforms and utilization of RNA interference technology have revealed that Akt signaling pathway components have distinct and isoform-specific roles in macrophage biology and inflammatory disease regulation, by controlling inflammatory cytokines, miRNAs, and functions including phagocytosis, autophagy, and cell metabolism. Herein, we review the current knowledge on the role of the Akt signaling pathway in macrophages, focusing on M1/M2 polarization and highlighting Akt isoform-specific functions.

Molecular mechanisms underlying Th1-like Treg generation and function

Since their ‘re-discovery’ more than two decades ago, FOXP3⁺ regulatory T cells (Tregs) have been an important subject of investigation in the biomedical field and our understanding of the mechanisms that drive their phenotype and function in health and disease has advanced tremendously. During the past few years it has become clear that Tregs are not a terminally differentiated population but show some degree of plasticity, and can, under specific environmental conditions, acquire the phenotype of effector T cells. In particular, recent works have highlighted the acquisition of a Th1-like phenotype by Tregs in several pathological environments. In this review we give an update on the concept of Treg plasticity and the advances in defining the molecular mechanisms that underlie the generation of Th1-like Tregs during an immune response and in different disease settings.

Identification of Significant Pathways Induced by PAX5 Haploinsufficiency Based on Protein-Protein Interaction Networks and Cluster Analysis in Raji Cell Line

PAX5 encodes a transcription factor essential for B-cell differentiation, and PAX5 haploinsufficiency is involved in tumorigenesis. There were few studies on how PAX5 haploinsufficiency regulated genes expression to promote tumorigenesis. In this study, we constructed the cell model of PAX5 haploinsufficiency using gene editing technology in Raji cells, detected differentially expressed genes in PAX5 haploinsufficiency Raji cells, and used protein-protein interaction networks and cluster analysis to comprehensively investigate the cellular pathways involved in PAX5 haploinsufficiency. The clusters of gene transcription, inflammatory and immune response, and cancer pathways were identified as three important pathways associated with PAX5 haploinsufficiency in Raji cells. These changes hinted that the mechanism of PAX5 haploinsufficiency promoting tumorigenesis may be related to genomic instability, immune tolerance, and tumor pathways.

Oligodendroglial fibroblast growth factor receptor 1 gene targeting protects mice from experimental autoimmune encephalomyelitis through ERK/AKT phosphorylation

Fibroblast growth factors (FGFs) exert diverse biological effects by binding and activation of specific fibroblast growth factor receptors (FGFRs). FGFs and FGFRs have been implicated in demyelinating pathologies including multiple sclerosis. In vitro activation of the FGF2/FGFR1 pathway results in downregulation of myelin proteins. FGF1, 2 and 9 have been shown to be involved in the pathology of multiple sclerosis. Recent studies on the function of oligodendroglial FGFR1 in a model of toxic demyelination showed that deletion of FGFR1 led to increased remyelination and preservation of axonal density and an increased number of mature oligodendrocytes. In the present study the in vivo function of oligodendroglial FGFR1 was characterized using an oligodendrocyte-specific genetic approach in the most frequently used model of multiple sclerosis the MOG_35-55 -induced EAE. Oligodendroglial FGFR1 deficient mice (referred to as Fgfr1^ind-/- ) showed a significantly ameliorated disease course in MOG_35-55 -induced EAE. Less myelin and axonal loss, and reduced lymphocyte and macrophage/microglia infiltration were found in Fgfr1^ind-/- mice. The reduction in disease severity in Fgfr1^ind-/- mice was accompanied by ERK/AKT phosphorylation, and increased expression of BDNF and TrkB. Reduced proinflammatory cytokine and chemokine expression was seen in Fgfr1^ind-/- mice compared with control mice. Considering that FGFR inhibitors are used in cancer trials, the oligodendroglial FGFR1 pathway may provide a new target for therapy in multiple sclerosis.

Cytotoxic Effects of Environmental Toxins on Human Glial Cells

Toxins produced by cyanobacteria and dinoflagellates have increasingly become a public health concern due to their degenerative effects on mammalian tissue and cells. In particular, emerging evidence has called attention to the neurodegenerative effects of the cyanobacterial toxin β-N-methylamino-L-alanine (BMAA). Other toxins such as the neurotoxins saxitoxin and ciguatoxin, as well as the hepatotoxic microcystin, have been previously shown to have a range of effects upon the nervous system. However, the capacity of these toxins to cause neurodegeneration in human cells has not, to our knowledge, been previously investigated. This study aimed to examine the cytotoxic effects of BMAA, microcystin-LR (MC-LR), saxitoxin (STX) and ciguatoxin (CTX-1B) on primary adult human astrocytes. We also demonstrated that α-lipoate attenuated MC-LR toxicity in primary astrocytes and characterised changes in gene expression which could potentially be caused by these toxins in primary astrocytes. Herein, we are the first to show that all of these toxins are capable of causing physiological changes consistent with neurodegeneration in glial cells, via oxidative stress and excitotoxicity, leading to a reduction in cell proliferation culminating in cell death. In addition, MC-LR toxicity was reduced significantly in astrocytes-treated α-lipoic acid. While there were no significant changes in gene expression, many of the probes that were altered were associated with neurodegenerative disease pathogenesis. Overall, this is important in advancing our current understanding of the mechanism of toxicity of MC-LR on human brain function in vitro, particularly in the context of neurodegeneration.

A Natural Variant of the T Cell Receptor-Signaling Molecule Vav1 Reduces Both Effector T Cell Functions and Susceptibility to Neuroinflammation

The guanine nucleotide exchange factor Vav1 is essential for transducing T cell antigen receptor signals and therefore plays an important role in T cell development and activation. Our previous genetic studies identified a locus on rat chromosome 9 that controls the susceptibility to neuroinflammation and contains a non-synonymous polymorphism in the major candidate gene Vav1. To formally demonstrate the causal implication of this polymorphism, we generated a knock-in mouse bearing this polymorphism (Vav1^R63W). Using this model, we show that Vav1^R63W mice display reduced susceptibility to experimental autoimmune encephalomyelitis (EAE) induced by MOG_35-55 peptide immunization. This is associated with a lower production of effector cytokines (IFN-γ, IL-17 and GM-CSF) by autoreactive CD4 T cells. Despite increased proportion of Foxp3+ regulatory T cells in Vav1^R63W mice, we show that this lowered cytokine production is intrinsic to effector CD4 T cells and that Treg depletion has no impact on EAE development. Finally, we provide a mechanism for the above phenotype by showing that the Vav1^R63W variant has normal enzymatic activity but reduced adaptor functions. Together, these data highlight the importance of Vav1 adaptor functions in the production of inflammatory cytokines by effector T cells and in the susceptibility to neuroinflammation.

The understanding of the physiological role of Vav1, a key regulator of T cell receptor signaling, was primarily inferred from studies using Vav1-deficient mice. Such models, however, provide little insight on how polymorphisms leading to quantitative changes in Vav1 activity could affect immune system functions. In the present study, we focused on a recently identified Vav1^R63W natural variant that has been supposed to play a central role in the susceptibility to neuroinflammation. Using a Vav1^R63W knock-in mouse model, we show that Vav1^R63W leads to defects in adaptor functions and reduces the susceptibility to experimental autoimmune encephalomyelitis, together with an intrinsic defect in the production of Th1/Th17 cytokines by autoreactive effector CD4 T cells. Thus, our study highlights the importance of Vav1 adaptor functions in CD4 T cells differentiation and suggests that genetic or acquired alterations of this Vav1 function could play a major role in susceptibility to Th1/Th17 mediated diseases.

AKT isoforms modulate Th1-like Treg generation and function in human autoimmune disease

Foxp3(+) regulatory T cells (Tregs) exhibit plasticity, which dictates their function. Secretion of the inflammatory cytokine IFNγ, together with the acquisition of a T helper 1 (Th1)-like effector phenotype as observed in cancer, infection, and autoimmune diseases, is associated with loss of Treg suppressor function through an unknown mechanism. Here, we describe the signaling events driving the generation of human Th1-Tregs. Using a genome-wide gene expression approach and pathway analysis, we identify the PI3K/AKT/Foxo1/3 signaling cascade as the major pathway involved in IFNγ secretion by human Tregs. Furthermore, we describe the opposing roles of AKT isoforms in Th1-Treg generation ex vivo Finally, we employ multiple sclerosis as an in vivo model with increased but functionally defective Th1-Tregs. We show that the PI3K/AKT/Foxo1/3 pathway is activated in ex vivo-isolated Tregs from untreated relapsing-remitting MS patients and that blockade of the pathway inhibits IFNγ secretion and restores the immune suppressive function of Tregs. These data define a fundamental pathway regulating the function of human Tregs and suggest a novel treatment paradigm for autoimmune diseases.

V-akt murine thymoma viral oncogene homolog 3 (AKT3) contributes to poor disease outcome in humans and mice with pneumococcal meningitis

Pneumococcal meningitis is the most common and severe form of bacterial meningitis. Fatality rates are substantial, and long-term sequelae develop in about half of survivors. Here, we have performed a prospective nationwide genetic association study using the Human Exome BeadChip and identified gene variants in encoding dynactin 4 (DCTN4), retinoic acid early transcript 1E (RAET1E), and V-akt murine thymoma viral oncogene homolog 3 (AKT3) to be associated with unfavourable outcome in patients with pneumococcal meningitis. No clinical replication cohort is available, so we validated the role of one of these targets, AKT3, in a pneumococcal meningitis mouse model. Akt3 deficient mice had worse survival and increased histopathology scores for parenchymal damage (infiltration) and vascular infiltration (large meningeal artery inflammation) but similar bacterial loads, cytokine responses, compared to wild-type mice. We found no differences in cerebrospinal fluid cytokine levels between patients with risk or non-risk alleles. Patients with the risk genotype (rs10157763, AA) presented with low scores on the Glasgow Coma Scale and high rate of epileptic seizures. Thus, our results show that AKT3 influences outcome of pneumococcal meningitis.

In vivo study of immunogenicity and kinetic characteristics of a quantum dot-labelled baculovirus

Nanomaterials conjugated with biomacromolecules, including viruses, have great potential for in vivo applications. Therefore, it is important to evaluate the safety of nanoparticle-conjugated macromolecule biomaterials (Nano-mbio). Although a number of studies have assessed the risks of nanoparticles and macromolecule biomaterials in living bodies, only a few of them investigated Nano-mbios. Here we evaluated the in vivo safety profile of a quantum dot-conjugated baculovirus (Bq), a promising new Nano-mbio, in mice. Each animal was injected twice intraperitoneally with 50 μg virus protein labelled with around 3*10(-5)nmol conjugated qds. Control animals were injected with PBS, quantum dots, baculovirus, or a mixture of quantum dots and baculovirus. Blood, tissues and body weight were analysed at a series of time points following both the first and the second injections. It turned out that the appearance and behaviour of the mice injected with Bq were similar to those injected with baculovirus alone. However, combination of baculovirus and quantum dot (conjugated or simply mixed) significantly induced stronger adaptive immune responses, and lead to a faster accumulation and longer existence of Cd in the kidneys. Thus, despite the fact that both quantum dot and baculovirus have been claimed to be safe in vivo, applications of Bq in vivo should be cautious. To our knowledge, this is the first study examining the interaction between a nanoparticle-conjugated virus and a living body from a safety perspective, providing a basis for in vivo application of other Nano-mbios.

In vivo quantitative magnetization transfer imaging correlates with histology during de- and remyelination in cuprizone-treated mice

The pool size ratio measured by quantitative magnetization transfer MRI is hypothesized to closely reflect myelin density, but their relationship has so far been confirmed mostly in ex vivo conditions. We investigate the correspondence between this parameter measured in vivo at 7.0 T, with Black Gold II staining for myelin fibres, and with myelin basic protein and beta-tubulin immunofluorescence in a hybrid longitudinal study of C57BL/6 and SJL/J mice treated with cuprizone, a neurotoxicant causing relatively selective myelin loss followed by spontaneous remyelination upon treatment suspension. Our results confirm that pool size ratio measurements correlate with myelin content, with the correlation coefficient depending on strain and staining method, and demonstrate the in vivo applicability of this MRI technique to experimental mouse models of multiple sclerosis.

Targeted GAS6 delivery to the CNS protects axons from damage during experimental autoimmune encephalomyelitis

Growth arrest-specific protein 6 (GAS6) is a soluble agonist of the TYRO3, AXL, MERTK (TAM) family of receptor tyrosine kinases identified to have anti-inflammatory, neuroprotective, and promyelinating properties. During experimental autoimmune encephalomyelitis (EAE), wild-type (WT) mice demonstrate a significant induction of Gas6, Axl, and Mertk but not Pros1 or Tyro3 mRNA. We tested the hypothesis that intracerebroventricular delivery of GAS6 directly into the CNS of WT mice during myelin oligodendrocyte glycoprotein (MOG)-induced EAE would improve the clinical course of disease relative to artificial CSF (ACSF)-treated mice. GAS6 did not delay disease onset, but significantly reduced the clinical scores during peak and chronic EAE. Mice receiving GAS6 for 28 d had preserved SMI31(+) neurofilament immunoreactivity, significantly fewer SMI32(+) axonal swellings and spheroids and less demyelination relative to ACSF-treated mice. Alternate-day subcutaneous IFNβ injection did not enhance GAS6 treatment effectiveness. Gas6(-/-) mice sensitized with MOG35-55 peptide exhibit higher clinical scores during late peak to early chronic disease, with significantly increased SMI32(+) axonal swellings and Iba1(+) microglia/macrophages, enhanced expression of several proinflammatory mRNA molecules, and decreased expression of early oligodendrocyte maturation markers relative to WT mouse spinal cords with scores for 8 consecutive days. During acute EAE, flow cytometry showed significantly more macrophages but not T-cell infiltrates in Gas6(-/-) spinal cords than WT spinal cords. Our data are consistent with GAS6 being protective during EAE by dampening the inflammatory response, thereby preserving axonal integrity and myelination.

Relationships between cobalamin, epidermal growth factor, and normal prions in the myelin maintenance of central nervous system

Cobalamin (Cbl), epidermal growth factor (EGF), and prions (PrPs) are key molecules for myelin maintenance in the central and peripheral nervous systems. Cbl and EGF increase normal prion (PrP(C)) synthesis and PrP(C) levels in rat spinal cord (SC) and elsewhere. Cbl deficiency increases PrP(C) levels in rat SC and cerebrospinal fluid (CSF), and decreases PrP(C)-mRNA levels in rat SC. The administration of anti-octapeptide repeat PrP(C) region antibodies (Abs) to Cbl-deficient (Cbl-D) rats prevents SC myelin lesions and a local increase in tumor necrosis factor (TNF)-α levels, whereas anti-TNF-α Abs prevent SC myelin lesions and the increase in SC and CSF PrP(C) levels. As it is known that both Cbl and EGF regulate SC PrP(C) synthesis independently, and that Cbl regulates SC EGF synthesis, EGF may play both Cbl-independent and Cbl-dependent roles. When Cbl-D rats undergo Cbl replacement therapy, SC PrP(C) levels are similar to those observed in Cbl-D rats. In rat frontal cortex (which is marginally affected by Cbl deficiency in histological terms), Cbl deficiency decreases PrP(C) levels and the increase induced by Cbl replacement leads to their normalization. Increased nerve PrP(C) levels are detected in the myelin lesions of the peripheral neuropathy of Cbl-D rats, and CSF PrP(C) levels are also increased in Cbl-D patients (but not in patients with Cbl-unrelated neurological diseases). Various common steps in the downstream signaling pathway of Cbl, EGF, and PrP(C) underlines the close relationship between the three molecules in keeping myelin normal.

HIV-1 Nef induces CCL5 production in astrocytes through p38-MAPK and PI3K/Akt pathway and utilizes NF-kB, CEBP and AP-1 transcription factors

The prevalence of HIV-associated neurocognitive disorders (HAND) remains high in patients infected with HIV-1. The production of pro-inflammatory cytokines by astrocytes/microglia exposed to viral proteins is thought to be one of the mechanisms leading to HIV-1- mediated neurotoxicity. In the present study we examined the effects of Nef on CCL5 induction in astrocytes. The results demonstrate that CCL5 is significantly induced in Nef-transfected SVGA astrocytes. To determine the mechanisms responsible for the increased CCL5 caused by Nef, we employed siRNA and chemical antagonists. Antagonists of NF-κB, PI3K, and p38 significantly reduced the expression levels of CCL5 induced by Nef transfection. Furthermore, specific siRNAs demonstrated that the Akt, p38MAPK, NF-κB, CEBP, and AP-1 pathways play a role in Nef-mediated CCL5 expression. The results demonstrated that the PI3K/Akt and p38 MAPK pathways, along with the transcription factors NF-κB, CEBP, and AP-1, are involved in Nef-induced CCL5 production in astrocytes.

Human immunodeficiency virus type 1 viral protein R (Vpr) induces CCL5 expression in astrocytes via PI3K and MAPK signaling pathways

Background

Neurocognitive impairments remain prevalent in HIV-1 infected individuals despite current antiretroviral therapies. It is increasingly becoming evident that astrocytes play a critical role in HIV-1 neuropathogenesis through the production of proinflammatory cytokines/chemokines. HIV-1 viral protein R (Vpr) plays an important role in neuronal dysfunction; however, its role in neuroinflammation is not well characterized. The major objective of this study was to determine the effect of Vpr in induction of proinflammatory chemokine CCL5 in astrocytes and to define the underlying mechanism(s).

Methods

SVGA astrocytes were either mock transfected or were transfected with a plasmid encoding HIV-1 Vpr, and the cells were harvested at different time intervals. The mRNA level of CCL5 expression was quantified using real-time RT-PCR, and cell culture supernatants were assayed for CCL5 protein concentration. Immunocytochemistry was performed on HIV-1 Vpr transfected astrocytes to check CCL5 expression. Various signaling mechanisms such as p38 MAPK, PI3K/Akt, NF-κB and AP-1 were explored using specific chemical inhibitors and siRNAs.

Results

HIV-1 Vpr transfected astrocytes exhibited time-dependent induction of CCL5 as compared to mock-transfected astrocytes at both the mRNA and protein level. Immunostained images of astrocytes transfected with HIV-1 Vpr also showed much higher accumulation of CCL5 in comparison to untransfected and mock-transfected astrocytes. Pre-treatment with NF-κB (SC514) and PI3K/Akt (LY294002) inhibitor partially abrogated CCL5 mRNA and protein expression levels as opposed to untreated controls after HIV-1 Vpr transfection. Specific siRNAs against p50 and p65 subunits of NF-κB, p38δ MAPK, Akt-2 and Akt-3, and AP-1 transcription factor substantially inhibited the production of CCL5 in HIV-1 Vpr transfected astrocytes.

Conclusion

These results demonstrate the ability of HIV-1 Vpr to induce CCL5 in astrocytes in a time-dependent manner. Furthermore, this effect was observed to be mediated by transcription factors NF-κB and AP-1 and involved the p38-MAPK and PI3K/Akt pathway.