Neuroprotection and remyelination after autoimmune demyelination in mice that inducibly overexpress CXCL1

Testosterone Inhibits Secretion of the Pro-Inflammatory Chemokine CXCL1 from Astrocytes

Astrocytes play an important role in the regulation of the inflammatory response in the CNS, e.g., in demyelinating diseases. Since the chemokine CXCL1 is known to be secreted by astrocytes and to have a pro-inflammatory effect on immune cells in the CNS, we verified the effect of testosterone on its secretion in vitro (in the astrocytic cell line DI TNC1). Testosterone reduced the increase in CXCL1 production caused by the pro-inflammatory agent lysophosphatidylcholine and restored the basal production level of CXCL1. The androgen receptor (present and functional in the studied cell line) was strongly suggested to mediate this effect-its non-steroid ligand flutamide exerted an agonist-like effect, mimicking the activity of testosterone itself on CXCL1 secretion. This novel mechanism has important implications for the known immunomodulatory effect of testosterone and potentially other androgenic hormones. It provides a potential explanation on the molecular level and shows that astrocytes are important players in inflammatory homeostasis in the CNS and its hormonal regulation. Therefore, it suggests new directions for the development of the therapeutic intervention.

Revolutionizing orofacial pain management: the promising potential of stem cell therapy

Orofacial pain remains a significant health issue in the United States. Pain originating from the orofacial region can be composed of a complex array of unique target tissue that contributes to the varying success of pain management. Long-term use of analgesic drugs includes adverse effects such as physical dependence, gastrointestinal bleeding, and incomplete efficacy. The use of mesenchymal stem cells for their pain relieving properties has garnered increased attention. In addition to the preclinical and clinical results showing stem cell analgesia in non-orofacial pain, studies have also shown promising results for orofacial pain treatment. Here we discuss the outcomes of mesenchymal stem cell treatment for pain and compare the properties of stem cells from different tissues of origin. We also discuss the mechanism underlying these analgesic/anti-nociceptive properties, including the role of immune cells and the endogenous opioid system. Lastly, advancements in the methods and procedures to treat patients experiencing orofacial pain with mesenchymal stem cells are also discussed.

Immune profiling in multiple sclerosis: a single-center study of 65 cytokines, chemokines, and related molecules in cerebrospinal fluid and serum

Introduction

The understanding of the pathophysiology of multiple sclerosis (MS) has evolved alongside the characterization of cytokines and chemokines in cerebrospinal fluid (CSF) and serum. However, the complex interplay of pro- and anti-inflammatory cytokines and chemokines in different body fluids in people with MS (pwMS) and their association with disease progression is still not well understood and needs further investigation. Therefore, the aim of this study was to profile a total of 65 cytokines, chemokines, and related molecules in paired serum and CSF samples of pwMS at disease onset.

Methods

Multiplex bead-based assays were performed and baseline routine laboratory diagnostics, magnetic resonance imaging (MRI), and clinical characteristics were assessed. Of 44 participants included, 40 had a relapsing-remitting disease course and four a primary progressive MS.

Results

There were 29 cytokines and chemokines that were significantly higher in CSF and 15 in serum. Statistically significant associations with moderate effect sizes were found for 34 of 65 analytes with sex, age, CSF, and MRI parameters and disease progression.

Discussion

In conclusion, this study provides data on the distribution of 65 different cytokines, chemokines, and related molecules in CSF and serum in newly diagnosed pwMS.

Expression and Prognostic Role of CXCL1 Gene in Colorectal Adenocarcinoma

In this manuscript, we have extensively examined expression and prognosis of CXCL1 gene in colorectal adenocarcinoma (COAD) using different cases of colorectal adenocarcinoma and tissues. To verify this, protein and mRNA expressions of cxcl1 were identified through RT-PCR and immunohistochemistry in 30 cases of colorectal adenocarcinoma and adjacent tissues, which were surgically resected from January to July 2021 in our hospital, and relationship between CXCL1 mRNA and clinicopathological features and protein expression was analyzed. CXCL 1 mRNA in COAD carcinoma's expression was considerably higher than in the adjacent normal intestine. At the same time, CXCL 1 diagnostic receiver operating characteristic (ROC) curve had preferably higher value of the diagnostic for area under curve (AUC) = 0.912, 95%, COAD (P < 0.001, CI = 0.825–0.969). We have observed that CXCL1 gene was closely linked with preoperative CEA level (P=0.007) and gross tumor typing (P=0.039). Finally, we have concluded that that CXCL1 can be a possible biomarker for stress prognosis and diagnosis.

Ataxin-3, The Spinocerebellar Ataxia Type 3 Neurodegenerative Disorder Protein, Affects Mast Cell Functions

Spinocerebellar ataxia type 3 (SCA3), also known as Machado-Joseph Disease, is a progressive neurodegenerative disorder characterized by loss of neuronal matter due to the expansion of the CAG repeat in the ATXN3/MJD1 gene and subsequent ataxin-3 protein. Although the underlying pathogenic protein expansion has been known for more than 20 years, the complexity of its effects is still under exploration. The ataxin-3 protein in its expanded form is known to aggregate and disrupt cellular processes in neuronal tissue but the role of the protein on populations of immune cells is unknown. Recently, mast cells have emerged as potential key players in neuroinflammation and neurodegeneration. Here, we examined the mast cell-related effects of ataxin-3 expansion in the brain tissues of 304Q ataxin-3 knock-in mice and SCA3 patients. We also established cultures of mast cells from the 304Q knock-in mice and examined the effects of 304Q ataxin-3 knock-in on the immune responses of these cells and on markers involved in mast cell growth, development and function. Specifically, our results point to a role for expanded ataxin-3 in suppression of mast cell marker CD117/c-Kit, pro-inflammatory cytokine TNF-α and NF-κB inhibitor IκBα along with an increased expression of the granulocyte-attracting chemokine CXCL1. These results are the beginning of a more holistic understanding of ataxin-3 and could point to the development of novel therapeutic targets which act on inflammation to mitigate symptoms of SCA3.

The Importance of CXCL1 in Physiology and Noncancerous Diseases of Bone, Bone Marrow, Muscle and the Nervous System

This review describes the role of CXCL1, a chemokine crucial in inflammation as a chemoattractant for neutrophils, in physiology and in selected major non-cancer diseases. Due to the vast amount of available information, we focus on the role CXCL1 plays in the physiology of bones, bone marrow, muscle and the nervous system. For this reason, we describe its effects on hematopoietic stem cells, myoblasts, oligodendrocyte progenitors and osteoclast precursors. We also present the involvement of CXCL1 in diseases of selected tissues and organs including Alzheimer’s disease, epilepsy, herpes simplex virus type 1 (HSV-1) encephalitis, ischemic stroke, major depression, multiple sclerosis, neuromyelitis optica, neuropathic pain, osteoporosis, prion diseases, rheumatoid arthritis, tick-borne encephalitis (TBE), traumatic spinal cord injury and West Nile fever.

Targeting IFN-λ Signaling Promotes Recovery from Central Nervous System Autoimmunity

Type III IFNs (IFNLs) are newly discovered cytokines, acting at epithelial and other barriers, that exert immunomodulatory functions in addition to their primary roles in antiviral defense. In this study, we define a role for IFNLs in maintaining autoreactive T cell effector function and limiting recovery in a murine model of multiple sclerosis (MS), experimental autoimmune encephalomyelitis. Genetic or Ab-based neutralization of the IFNL receptor (IFNLR) resulted in lack of disease maintenance during experimental autoimmune encephalomyelitis, with loss of CNS Th1 effector responses and limited axonal injury. Phenotypic effects of IFNLR signaling were traced to increased APC function, with associated increase in T cell production of IFN-γ and GM-CSF. Consistent with this, IFNL levels within lesions of CNS tissues derived from patients with MS were elevated compared with MS normal-appearing white matter. Furthermore, expression of IFNLR was selectively elevated in MS active lesions compared with inactive lesions or normal-appearing white matter. These findings suggest IFNL signaling as a potential therapeutic target to prevent chronic autoimmune neuroinflammation.

Oligodendrocytes and Microglia: Key Players in Myelin Development, Damage and Repair

Oligodendrocytes, the myelin-making cells of the CNS, regulate the complex process of myelination under physiological and pathological conditions, significantly aided by other glial cell types such as microglia, the brain-resident, macrophage-like innate immune cells. In this review, we summarize how oligodendrocytes orchestrate myelination, and especially myelin repair after damage, and present novel aspects of oligodendroglial functions. We emphasize the contribution of microglia in the generation and regeneration of myelin by discussing their beneficial and detrimental roles, especially in remyelination, underlining the cellular and molecular components involved. Finally, we present recent findings towards human stem cell-derived preclinical models for the study of microglia in human pathologies and on the role of microbiome on glial cell functions.

Assessment of Immunological Potential of Glial Restricted Progenitor Graft In Vivo-Is Immunosuppression Mandatory?

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease, causing motor neuron and skeletal muscle loss and death. One of the promising therapeutic approaches is stem cell graft application into the brain; however, an immune reaction against it creates serious limitations. This study aimed to research the efficiency of glial restricted progenitors (GRPs) grafted into murine CNS (central nervous system) in healthy models and the SOD1G93A ALS disease model. The cellular grafts were administered in semiallogenic and allogeneic settings. To investigate the models of immune reaction against grafted GRPs, we applied three immunosuppressive/immunomodulatory regimens: preimplantation factor (PiF); Tacrolimus; and CTLA-4, MR1 co-stimulatory blockade. We tracked the cells with bioluminescence imaging (BLI) in vivo to study their survival. The immune response character was evaluated with brain tissue assays and multiplex ELISA in serum and cerebrospinal fluid (CSF). The application of immunosuppressive drugs is disputable when considering cellular transplants into the immune-privileged site/brain. However, our data revealed that semiallogenic GRP graft might survive inside murine CNS without the necessity to apply any immunomodulation or immunosuppression, whereas, in the situation of allogeneic mouse setting, the combination of CTLA-4, MR1 blockade can be considered as the best immunosuppressive option.

Patient-derived glial enriched progenitors repair functional deficits due to white matter stroke and vascular dementia in rodents

Subcortical white matter stroke (WMS) accounts for up to 30% of all stroke events. WMS damages primarily astrocytes, axons, oligodendrocytes, and myelin. We hypothesized that a therapeutic intervention targeting astrocytes would be ideally suited for brain repair after WMS. We characterize the cellular properties and in vivo tissue repair activity of glial enriched progenitor (GEP) cells differentiated from human-induced pluripotent stem cells, termed hiPSC-derived GEPs (hiPSC-GEPs). hiPSC-GEPs are derived from hiPSC-neural progenitor cells via an experimental manipulation of hypoxia inducible factor activity by brief treatment with a prolyl hydroxylase inhibitor, deferoxamine. This treatment permanently biases these cells to further differentiate toward an astrocyte fate. hiPSC-GEPs transplanted into the brain in the subacute period after WMS in mice migrated widely, matured into astrocytes with a prorepair phenotype, induced endogenous oligodendrocyte precursor proliferation and remyelination, and promoted axonal sprouting. hiPSC-GEPs enhanced motor and cognitive recovery compared to other hiPSC-differentiated cell types. This approach establishes an hiPSC-derived product with easy scale-up capabilities that might be effective for treating WMS.

CXCL5 Cytokine Is a Major Factor in Platelet-Rich Plasma's Preservation of Erectile Function in Rats After Bilateral Cavernous Nerve Injury

BACKGROUND

The neuro-protective and tissue-protective properties of platelet-rich plasma (PRP) have been demonstrated through treating bilateral cavernous nerve (CN) injury in rats, although the underlying mechanisms have not been fully clarified.

AIM

To determine factors released from PRP and explore their role in mediating preservation of erectile function (EF) in a rat model of CN injury.

METHODS

Male Sprague-Dawley rats (aged 10 weeks) were used in this study. 6 rats were used to obtain blood for PRP and whole plasma preparation. We probed samples using a cytokine antibody array and performed enzyme-linked immunosorbent assay (ELISA). We determined the expression patterns of C-X-C motif chemokine ligand 5 (CXCL5) and receptors in the major pelvic ganglion (MPG) and corpus cavernosum via immunostaining. 32 rats were divided into 4 groups based on the type of injection received: (i) sham, (ii) vehicle, (iii) 400 μL of PRP, and (iv) 30 ng/kg of CXCL5. Groups 2-4 were subjected to bilateral CN crush (BCNC) injury. 4 weeks later, EF was assessed by CN electrostimulation, and CNs and penile tissue were collected for histological analysis.

OUTCOME

Cytokine antibody array, ELISA, erectile response, and immunofluorescence staining readings.

RESULTS

The PRP contained high levels of CXCL5. MPG neurons expressed CXCL5 and CXCR2. PRP intracavernous injection stabilized CXCR2 and increased CXCL5 expression in the MPG after BCNC, thus enhancing neuroprotection. CXCL5 injection improved BCNC-induced erectile dysfunction by preventing smooth muscle atrophy.

CLINICAL IMPLICATIONS

The therapeutic efficacy of PRP in CN injury-induced erectile dysfunction may arise from the synergy among multiple biomolecules. Our study serves as a basis for future studies on PRP formulation to provide safe and effective medications for the maintenance of EF after radical prostatectomy in patients with prostate cancer.

STRENGTHS & LIMITATIONS

A strength of our study is that our model was able to isolate the role of cytokines, specifically CXCL5, as part of the mechanism responsible for PRP's protective properties. However, the rat cytokine array provided limited experimental targets. The rats used were not at the age corresponding to prostate cancer patients in clinical settings. Our study did not explore CXCL5 blocking in the PRP group. Finally, the main protein quantification results by western blotting were hampered because of small tissue samples.

CONCLUSIONS

This study provides evidence for the role of CXCL5 and CXCR2 as mediators of PRP effects in the preservation of EF after CN injury. Wu YN, Liao CH, Chen KC, et al. CXCL5 Cytokine Is a Major Factor in Platelet-Rich Plasma's Preservation of Erectile Function in Rats After Bilateral Cavernous Nerve Injury. J Sex Med 2021;18:698-710.

Chemokines as the critical factors during bladder cancer progression: an overview

Bladder cancer (BCa) is one of the most frequent urogenital malignancies which is mainly observed among men. There are various genetic and environmental risk factors associated with BCa progression. Transurethral endoscopic resection and open ablative surgery are the main treatment options for muscle invasive BCa. BCG therapy is also employed following the endoscopic resection to prevent tumor relapse. The tumor microenvironment is the main interaction site of tumor cells and immune system in which the immune cells are recruited via chemokines and chemokine receptors. In present review we summarized the main chemokines and chemokine receptors which have been associated with histopathological features of BCa patients in the world. This review highlights the chemokines and chemokine receptors as critical markers in early detection and therapeutic purposes among BCa patients and clarifies their molecular functions during BCa progression and metastasis.

Oligodendrocytes modulate the immune-inflammatory response in EAE via TNFR2 signaling

The pleotropic cytokine tumor necrosis factor (TNF) is involved in the pathophysiology of multiple sclerosis (MS). In various models of MS, including experimental autoimmune encephalomyelitis (EAE), the membrane-bound form of TNF (tmTNF), which signals primarily via TNFR2, mediates protective and reparative effects, whereas the soluble form (solTNF), which signals primarily via TNFR1, promotes pro-inflammatory and detrimental functions. In this study, we investigated the role of TNFR2 expressed in oligodendrocytes in the early phase of EAE pathogenesis. We demonstrated that mice with specific ablation of oligodendroglial TNFR2 displayed early onset and higher peak of motor dysfunction when subjected to EAE, in advance of which accelerated infiltration of immune cells was observed as early as 10 days post EAE induction. The immune cell influx was preceded by microglial activation and increased blood brain barrier permeability. Lack of oligodendroglial TNFR2 accelerated the expression of inflammatory cytokines as well as expression and activation of the inflammasome. Gene expression profiling of oligodendrocytes sorted from the spinal cord 14 days post EAE induction showed robust upregulation of inflammatory genes, some of which were elevated in cells lacking TNFR2 compared to controls. Together, our data demonstrate that oligodendrocytes are directly involved in inflammation and immune modulation in CNS disease and this function is regulated, at least in part, by TNFR2.

LXRs regulate features of age-related macular degeneration and may be a potential therapeutic target

Effective treatments and animal models for the most prevalent neurodegenerative form of blindness in elderly people, called age-related macular degeneration (AMD), are lacking. Genome-wide association studies have identified lipid metabolism and inflammation as AMD-associated pathogenic pathways. Given liver X receptors (LXRs), encoded by the nuclear receptor subfamily 1 group H members 2 and 3 (NR1H3 and NR1H2), are master regulators of these pathways, herein we investigated the role of LXR in human and mouse eyes as a function of age and disease and tested the therapeutic potential of targeting LXR. We identified immunopositive LXR fragments in human extracellular early dry AMD lesions and a decrease in LXR expression within the retinal pigment epithelium (RPE) as a function of age. Aged mice lacking LXR presented with isoform-dependent ocular pathologies. Specifically, loss of the Nr1h3 isoform resulted in pathobiologies aligned with AMD, supported by compromised visual function, accumulation of native and oxidized lipids in the outer retina, and upregulation of ocular inflammatory cytokines, while absence of Nr1h2 was associated with ocular lipoidal degeneration. LXR activation not only ameliorated lipid accumulation and oxidant-induced injury in RPE cells but also decreased ocular inflammatory markers and lipid deposition in a mouse model, thereby providing translational support for pursuing LXR-active pharmaceuticals as potential therapies for dry AMD.

Polarizing receptor activation dissociates fibroblast growth factor 2 mediated inhibition of myelination from its neuroprotective potential

Fibroblast growth factor (FGF) signaling contributes to failure of remyelination in multiple sclerosis, but targeting this therapeutically is complicated by its functional pleiotropy. We now identify FGF2 as a factor up-regulated by astrocytes in active inflammatory lesions that disrupts myelination via FGF receptor 2 (FGFR2) mediated activation of Wingless (Wnt) signaling; pharmacological inhibition of Wnt being sufficient to abrogate inhibition of myelination by FGF2 in tissue culture. Using a novel FGFR1-selective agonist (F2 V2) generated by deleting the N-terminal 26 amino acids of FGF2 we demonstrate polarizing signal transduction to favor FGFR1 abrogates FGF mediated inhibition of myelination but retains its ability to induce expression of pro-myelinating and immunomodulatory factors that include Cd93, Lif, Il11, Hbegf, Cxcl1 and Timp1. Our data provide new insights into the mechanistic basis of remyelination failure in MS and identify selective activation of FGFR1 as a novel strategy to induce a neuroprotective signaling environment in multiple sclerosis and other neurological diseases.

Current Paradigms of Tolerogenic Dendritic Cells and Clinical Implications for Systemic Lupus Erythematosus

Tolerogenic dendritic cells (tolDCs) are central players in the initiation and maintenance of immune tolerance and subsequent prevention of autoimmunity. Recent advances in treatment of autoimmune diseases including systemic lupus erythematosus (SLE) have focused on inducing specific tolerance to avoid long-term use of immunosuppressive drugs. Therefore, DC-targeted therapies to either suppress DC immunogenicity or to promote DC tolerogenicity are of high interest. This review describes details of the typical characteristics of in vivo and ex vivo tolDC, which will help to select a protocol that can generate tolDC with high functional quality for clinical treatment of autoimmune disease in individual patients. In addition, we discuss the recent studies uncovering metabolic pathways and their interrelation intertwined with DC tolerogenicity. This review also highlights the clinical implications of tolDC-based therapy for SLE treatment, examines the current clinical therapeutics in patients with SLE, which can generate tolDC in vivo, and further discusses on possibility and limitation on each strategy. This synthesis provides new perspectives on development of novel therapeutic approaches for SLE and other autoimmune diseases.

The Possible Role of Telomere Length and Chemokines in the Aging Process: A Transdiagnostic Review in Psychiatry

Background:

Psychiatric disorders are common, reaching a worldwide prevalence of 29.2%. They are associated with a high risk of premature death and with accelerated aging in clinical, molecular and neuroimaging studies. Recently, there is strong evidence suggesting a possible role of telomere length and chemokines in aging processes in psychiatric disorders.

Objective:

We aimed to review the literature on telomere length and chemokines and its association with early aging in mental illnesses on a transdiagnostic approach.

Results:

The review highlights the association between psychiatric disorders and early aging. Several independent studies have reported shorter telomere length and dysregulations on levels of circulating chemokines in schizophrenia, bipolar disorder, major depressive disorder, and anxiety disorders, suggesting a complex interaction between these markers in a transdiagnostic level. However, studies have investigated the inflammatory markers and telomere shortening separately and associated with a particular diagnosis, rather than as a transdiagnostic biological feature.

Conclusion:

There is consistent evidence supporting the relationship between accelerated aging, telomere length, and chemokines in mental disorders, but they have been studied individually. Thus, more research is needed to improve the knowledge of accelerated senescence and its biomarkers in psychiatry, not only individually in each diagnosis, but also based on a transdiagnostic perspective. Moreover, further research should try to elucidate how the intricate association between the chemokines and telomeres together may contribute to the aging process in psychiatric disorders.

Disrupted CXCR2 Signaling in Oligodendroglia Lineage Cells Enhances Myelin Repair in a Viral Model of Multiple Sclerosis

CXCR2 is a chemokine receptor expressed on oligodendroglia that has been implicated in the pathogenesis of neuroinflammatory demyelinating diseases as well as enhancement of the migration, proliferation, and myelin production by oligodendroglia. Using an inducible proteolipid protein (Plp) promoter-driven Cre-loxP recombination system, we were able to assess how timed ablation of Cxcr2 in oligodendroglia affected disease following intracranial infection with the neurotropic JHM strain of mouse hepatitis virus (JHMV). Generation of Plp-Cre-ER(T)::Cxcr2flox/flox transgenic mice (termed Cxcr2-CKO mice) allows for Cxcr2 to be silenced in oligodendrocytes in adult mice following treatment with tamoxifen. Ablation of oligodendroglia Cxcr2 did not influence clinical severity in response to intracranial infection with JHMV. Infiltration of activated T cells or myeloid cells into the central nervous system (CNS) was not affected, nor was the ability to control viral infection. In addition, the severity of demyelination was similar between tamoxifen-treated mice and vehicle-treated controls. Notably, deletion of Cxcr2 resulted in increased remyelination, as assessed by g-ratio (the ratio of the inner axonal diameter to the total outer fiber diameter) calculation, compared to that in vehicle-treated control mice. Collectively, our findings argue that CXCR2 signaling in oligodendroglia is dispensable with regard to contributing to neuroinflammation, but its deletion enhances remyelination in a preclinical model of the human demyelinating disease multiple sclerosis (MS).IMPORTANCE Signaling through the chemokine receptor CXCR2 in oligodendroglia is important for developmental myelination in rodents, while chemical inhibition or nonspecific genetic deletion of CXCR2 appears to augment myelin repair in animal models of the human demyelinating disease multiple sclerosis (MS). To better understand the biology of CXCR2 signaling on oligodendroglia, we generated transgenic mice in which Cxcr2 is selectively ablated in oligodendroglia upon treatment with tamoxifen. Using a viral model of neuroinflammation and demyelination, we demonstrate that genetic silencing of CXCR2 on oligodendroglia did not affect clinical disease, neuroinflammation, or demyelination, yet there was increased remyelination. These findings support and extend previous findings suggesting that targeting CXCR2 may offer a therapeutic avenue for enhancing remyelination in patients with demyelinating diseases.

The contribution of astrocytes to the neuroinflammatory response in multiple sclerosis and experimental autoimmune encephalomyelitis

Neuroinflammation is the coordinated response of the central nervous system (CNS) to threats to its integrity posed by a variety of conditions, including autoimmunity, pathogens and trauma. Activated astrocytes, in concert with other cellular elements of the CNS and immune system, are important players in the modulation of the neuroinflammatory response. During neurological disease, they produce and respond to cellular signals that often lead to dichotomous processes, which can promote further damage or contribute to repair. This occurs also in multiple sclerosis (MS), where astrocytes are now recognized as key components of its immunopathology. Evidence supporting this role has emerged not only from studies in MS patients, but also from animal models, among which the experimental autoimmune encephalomyelitis (EAE) model has proved especially instrumental. Based on this premise, the purpose of the present review is to summarize the current knowledge of astrocyte behavior in MS and EAE. Following a brief description of the pathological characteristics of the two diseases and the main functional roles of astrocytes in CNS physiology, we will delve into the specific responses of this cell population, analyzing MS and EAE in parallel. We will define the temporal and anatomical profile of astroglial activation, then focus on key processes they participate in. These include: (1) production and response to soluble mediators (e.g., cytokines and chemokines), (2) regulation of oxidative stress, and (3) maintenance of BBB integrity and function. Finally, we will review the state of the art on the available methods to measure astroglial activation in vivo in MS patients, and how this could be exploited to optimize diagnosis, prognosis and treatment decisions. Ultimately, we believe that integrating the knowledge obtained from studies in MS and EAE may help not only better understand the pathophysiology of MS, but also uncover new signals to be targeted for therapeutic intervention.

Analogues of ERβ ligand chloroindazole exert immunomodulatory and remyelinating effects in a mouse model of multiple sclerosis

Pharmaceutical agents currently approved for the treatment of multiple sclerosis reduce relapse rates, but do not reverse or prevent neurodegeneration nor initiate myelin repair. The highly selective estrogen receptor (ER) β ligand chloroindazole (IndCl) shows particular promise promoting both remyelination while reducing inflammatory cytokines in the central nervous system of mice with experimental autoimmune encephalomyelitis. To optimize these benefits, we developed and screened seven novel IndCl analogues for their efficacy in promoting primary oligodendrocyte (OL) progenitor cell survival, proliferation, and differentiation in vitro by immunohistochemistry. Two analogues, IndCl-o-chloro and IndCl-o-methyl, induced proliferation and differentiation equivalent to IndCl and were selected for subsequent in vivo evaluation for their impact on clinical disease course, white matter pathology, and inflammation. Both compounds ameliorated disease severity, increased mature OLs, and improved overall myelination in the corpus callosum and white matter tracts of the spinal cord. These effects were accompanied by reduced production of the OL toxic molecules interferon-γ and chemokine (C-X-C motif) ligand, CXCL10 by splenocytes with no discernable effect on central nervous system-infiltrating leukocyte numbers, while IndCl-o-methyl also reduced peripheral interleukin (IL)−17. In addition, expression of the chemokine CXCL1, which is associated with developmental oligodendrogenesis, was upregulated by IndCl and both analogues. Furthermore, callosal compound action potential recordings from analogue-treated mice demonstrated a larger N1 component amplitude compared to vehicle, suggesting more functionally myelinated fibers. Thus, the o-Methyl and o-Chloro IndCl analogues represent a class of ERβ ligands that offer significant remyelination and neuroprotection as well as modulation of the immune system; hence, they appear appropriate to consider further for therapeutic development in multiple sclerosis and other demyelinating diseases.

Short and Long-Term Changes in Social Odor Recognition and Plasma Cytokine Levels Following Oxygen (16O) Ion Radiation Exposure

Future long-duration space missions will involve travel outside of the Earth’s magnetosphere protection and will result in astronauts being exposed to high energy and charge (HZE) ions and protons. Exposure to this type of radiation can result in damage to the central nervous system and deficits in numerous cognitive domains that can jeopardize mission success. Social processing is a cognitive domain that is important for people living and working in groups, such as astronauts, but it has received little attention in terms of HZE ion exposure. In the current study, we assessed the effects of whole-body oxygen ion (¹⁶O; 1000 MeV/n) exposure (1 or 10 cGy) on social odor recognition memory in male Long-Evans rats at one and six months following exposure. Radiation exposure did not affect rats’ preferences for a novel social odor experienced during Habituation at either time point. However, rats exposed to 10 cGy displayed short and long-term deficits in 24-h social recognition. In contrast, rats exposed to 1 cGy only displayed long-term deficits in 24-h social recognition. While an age-related decrease in Ki67+ staining (a marker of cell proliferation) was found in the subventricular zone, it was unaffected by radiation exposure. At one month following exposure, plasma KC/GRO (CXCL1) levels were elevated in the 1 cGy rats, but not in the 10 cGy rats, suggesting that peripheral levels of this cytokine could be associated with intact social recognition at earlier time points following radiation exposure. These results have important implications for long-duration missions and demonstrate that behaviors related to social processing could be negatively affected by HZE ion exposure.

Association between the different duration of breastfeeding and attention deficit/hyperactivity disorder in children: a systematic review and meta-analysis

Objectives: To summarize the current evidence on the association between maternal breastfeeding and the occurrence of attention deficit/hyperactivity disorder (ADHD) in offspring. Methods: We searched for studies published in English before May 2018 using the PubMed, EMBASE, Cochrane, and Web of Science databases. We included cohort studies, case-control studies, and cross-sectional studies, that focused on the association between maternal breastfeeding and the occurrence of ADHD in offspring. Random effects models were used for combined analyses. Results: Two cohort studies, 7 case-control studies and 3 cross-sectional studies, with 3,686 cases and 106,907 participants, were included. Children with any maternal breastfeeding had a lower incidence of ADHD than children who were never breastfed (odds ratio [OR]: 0.70; 95% confidence interval [CI]:0.52-0.93). Further analyses also showed associations between reduced ADHD incidence and duration of breastfeeding. Children breastfed for over 1 month, over 3 months, over 6 months, and over 12 months had a lower incidence of ADHD than children breastfed for less than 1 month (OR: 0.20; 95% CI: 0.11-0.38), less than 3 months (OR: 0.33; 95% CI: 0.23-0.47), less than 6 months (OR: 0.50; 95% CI: 0.41-0.61), and less than 12 months (OR: 0.55; 95% CI: 0.37-0.81), respectively. These results were stable in the 1-month, 3-month, and 6-month breastfeeding groups. Conclusion: With our meta-analysis, we provide evidence that maternal breastfeeding may reduce the risk of ADHD in children. The causality of this relationship and underlying mechanisms need to be explored in future prospective studies.

Anti-drug Antibodies Against a Novel Humanized Anti-CD20 Antibody Impair Its Therapeutic Effect on Primary Biliary Cholangitis in Human CD20- and FcγR-Expressing Mice

There is considerable interest in expanding B cell-targeted therapies in human autoimmune diseases. However, clinical trials in human primary biliary cholangitis (PBC) using a chimeric antibody against human CD20 (hCD20) have showed limited efficacy. Two potential explanations for these disappointing results are the appearance of anti-drug antibodies (ADAs) and the high frequency of patients with moderate PBC or patients who had failed ursodeoxycholic acid treatment. Here, we studied a novel humanized IgG1 antibody against hCD20 and explored its efficacy in early stage PBC using a well-defined murine model. We developed a unique murine model consisting of dnTGF-βRII mice expressing hCD20 and human Fcγ receptors (hFcγRs). Beginning at 4–6 weeks of age, equivalent to stage I/II human PBC, female mice were given weekly injections of an anti-hCD20 antibody (TKM-011) or vehicle control, and monitored for liver histology as well as a broad panel of immunological readouts. After 16 weeks' treatment, we observed a significant reduction in portal inflammation, a decrease in liver-infiltrating mononuclear cells as well as a reduction in liver CD8⁺ T cells. Importantly, direct correlations between numbers of liver non-B cells and B cells (r = 0.7426, p = 0.0006) and between numbers of liver memory CD8⁺ T cells and B cells (r = 0.6423, p = 0.0054) were apparent. Accompanying these changes was a dramatic reduction in anti-mitochondrial antibodies (AMAs), interleukin (IL)-12p40 and IL-5, and elevated levels of the anti-inflammatory chemokine CXCL1/KC. In mice that developed ADAs, clinical improvements were less pronounced. Sustained treatment with B cell-targeted therapies may broadly inhibit effector pathways in PBC, but may need to be administered early in the natural history of PBC.

Different roles of CXCR1 and CXCR2 in HTLV-1 carriers and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) patients

One of the prominent features of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is the excessive recruitment of leukocytes to the central nervous system (CNS), which leads to an inflammatory response-with chemokines and their receptors playing the main role in this recruitment. The aim of the study was to examine the relation of CXCR1 and CXCR2, both of which are involved in the trafficking of lymphocytes into the CNS, with the outcome of HTLV-1 infection. The mRNA levels of CXCR1 and CXCR2 were examined in peripheral blood mononuclear cells (PBMCs) of HAM/TSP patients, HTLV-1 asymptomatic carriers (ACs), and healthy controls (HCs). Furthermore, the frequency of CD4⁺ and CD8⁺ T cells expressing CXCR1 and CXCR2 was evaluated in the studied groups. The results of the present study showed a substantial increase in the mean mRNA expression of CXCR2 in the HAM/TSP patients compared to the HCs and ACs (p < 0.001). A positive correlation was also found between PVL and CXCR2 mRNA expression in the total population of HTLV-1-infected subjects (R = 0.526, p < 0.001). Moreover, the percentage of CD8⁺ CXCR2-expressing cells was higher in HAM/TSP patients compared to ACs and HCs (p < 0.05, p < 0.01, respectively). Although the percentage of CD4⁺ CXCR2-expressing cells was higher in HAM/TSP patients than in ACs and HCs, a significant difference was only found between HAM/TSP patients and HCs (p < 0.05). No significant difference in the CXCR1 mRNA expression was observed in the studied groups. The frequency of the CD8⁺ CXCR1- and CD4⁺ CXCR1-expressing cells was significantly lower in HAM/TSP patients than in ACs and HCs (p < 0.001 and p < 0.01, respectively). In conclusion, the high frequency of CXCR2 CD8⁺ T cells and the high levels of CXCR2 mRNA expression in HAM/TSP patients are associated with disease pathogenesis, while the high frequencies of CXCR1 T cells in ACs might suggest that these cells act as effector CD8 T cells and are involved in controlling the viral spread and modulation of the immune response.

Epinephrine stimulates CXCL1 IL-1α, IL-6 secretion in isolated mouse limb muscle

Catecholamines stimulate interleukin‐6 (IL‐6) secretion in skeletal muscles. However, whether other cytokines are secreted is currently unknown. Skeletal muscle ex vivo preparations commonly used to study cytokine secretion have dealt with limitations including auto‐oxidation of catecholamines. The use of metal chelators could be an alternative to avoid auto‐oxidation and allow catecholamines to be used at physiological doses. We exposed isolated soleus muscles to 1 or 100 ng/mL epinephrine (EPI) and collected bath samples at 1 and 2 h for multiplex cytokine analysis. Keratinocyte chemoattractant (CXCL1), IL‐6, and IL‐1α were significantly elevated by 100 ng/mL exposure, but not by 1 ng/mL (median [CXCL1] (2 h) = 83 pg/mL; [IL‐6] = 19 pg/mL; IL‐1α = 7.5 pg/mL). CXCL1 and IL‐6 were highly correlated in each sample (P = 0.0001). A second experiment combined the metal chelator, deferoxamine mesylate (DFO), to prevent EPI autoxidation, with 2 ng/mL EPI and 10.5 ng/mL norepinephrine (NOREPI) to mimic peak exercise. Unexpectedly, DFO alone stimulated both IL‐6 and CXCL1 secretion, but together with EPI and NOREPI had no additional effects. Stimulation of cytokine secretory responses from skeletal muscle cells in response to DFO thus precludes its use as a chelating agent in ex vivo models. In conclusion, 100 ng/mL EPI stimulates a robust secretory CXCL1 response, which together with IL‐6 and IL‐1α, may constitute an adrenal‐muscle endocrine response system.

Peritoneal and Systemic Responses of Obese Type II Diabetic Rats to Chronic Exposure to a Hyperbranched Polyglycerol-Based Dialysis Solution

Metabolic syndrome (MetS) is commonly observed among peritoneal dialysis (PD) patients, and hyperbranched polyglycerol (HPG) is a promising glucose-sparing osmotic agent for PD. However, the biocompatibility of a HPG-based PD solution (HPG) in subjects with MetS has not been investigated. This study compared the local and systemic effects of a HPG solution with conventional physioneal (PYS) and icodextrin (ICO) PD solutions in rats with MetS. Obese type 2 diabetic ZSF1 rats received a daily intraperitoneal injection of PD solutions (10 mL) for 3 months. The peritoneal membrane (PM) function was determined by ultrafiltration (UF), and the systemic responses were determined by profiling blood metabolic substances, cytokines and oxidative status. Tissue damage was assessed by histology. At the end of the 3-month treatment with PD solutions, PM damage and UF loss in both the PYS and ICO groups were greater than those in the HPG group. Blood analyses showed that compared to the baseline control, the rats in the HPG group exhibited a significant decrease only in serum albumin and IL-6 and a minor glomerular injury, whereas in both the PYS and ICO groups, there were more significant decreases in serum albumin, antioxidant activity, IL-6, KC/GRO (CXCL1) and TNF-α (in ICO only) as well as a more substantial glomerular injury compared to the HPG group. Furthermore, PYS increased serum creatinine, serum glucose and urine production. In conclusion, compared to PYS or ICO solutions, the HPG solution had less adverse effects locally on the PM and systemically on distant organs (e.g. kidneys) and the plasma oxidative status in rats with MetS.

Bevacizumab Diminishes Inflammation in an Acute Endotoxin-Induced Uveitis Model

Introduction: Uveitis is an eye disease characterized by inflammation of the uvea and an early and exhaustive diagnosis is essential for its treatment. The aim of our study is to assess the potential toxicity and anti-inflammatory efficacy of Bevacizumab in an experimental uveitis model by subcutaneously injecting lipopolysaccharide into Lewis rats and to clarify its mechanism. Material and Methods: Blood-aqueous barrier integrity was assessed 24 h after endotoxin-induced uveitis (EIU) by analyzing two parameters: cell count and protein concentration in aqueous humors. Histopathology of all eye structures was also studied. Enzyme-linked immunosorbent analyses of the aqueous humor samples were performed in order to calculate the diverse chemokine and cytokine protein levels and oxidative stress-related markers were also evaluated. Results: The aqueous humor's cellular content significantly increased in the group treated with only Bevacizumab, but it had no effect on retina histopathological grading. Nevertheless, the inflammation noted in ocular structures when administering Bevacizumab with endotoxin was mostly prevented since aqueous humor cell content considerably lowered, and concomitantly with a sharp drop in uveal, vitreous, and retina histopathological grading. The values of the multi-faceted cytokine IL-2 also significantly decreased (p < 0.05 vs. endotoxin group), and the protective IL-6 and IL-10 cytokines values rose with related anti-oxidant system recovery (p < 0.05 vs. endotoxin group). Concurrently, some related M1 macrophage chemokines substantially increased, e.g., GRO/KC, a chemokine that also displays any kind of protective role. Conclusion: All these results revealed that 24 h after being administered, Bevacizumab treatment in EIU significantly prevented inflammation in various eye structures and correct results in efficacy vs. toxicity balance were obtained.

To Be or Not to Be: Environmental Factors that Drive Myelin Formation during Development and after CNS Trauma

Oligodendrocytes are specialized glial cells that myelinate central nervous system (CNS) axons. Historically, it was believed that the primary role of myelin was to compactly ensheath axons, providing the insulation necessary for rapid signal conduction. However, mounting evidence demonstrates the dynamic importance of myelin and oligodendrocytes, including providing metabolic support to neurons and regulating axon protein distribution. As such, the development and maintenance of oligodendrocytes and myelin are integral to preserving CNS homeostasis and supporting proper functioning of widespread neural networks. Environmental signals are critical for proper oligodendrocyte lineage cell progression and their capacity to form functional compact myelin; these signals are markedly disturbed by injury to the CNS, which may compromise endogenous myelin repair capabilities. This review outlines some key environmental factors that drive myelin formation during development and compares that to the primary factors that define a CNS injury milieu. We aim to identify developmental factors disrupted after CNS trauma as well as pathogenic factors that negatively impact oligodendrocyte lineage cells, as these are potential therapeutic targets to promote myelin repair after injury or disease.

Increase in chemokine CXCL1 by ERβ ligand treatment is a key mediator in promoting axon myelination

Estrogen receptor β (ERβ) ligands promote remyelination in mouse models of multiple sclerosis. Recent work using experimental autoimmune encephalomyelitis (EAE) has shown that ERβ ligands induce axon remyelination, but impact peripheral inflammation to varying degrees. To identify if ERβ ligands initiate a common immune mechanism in remyelination, central and peripheral immunity and pathology in mice given ERβ ligands at peak EAE were assessed. All ERβ ligands induced differential expression of cytokines and chemokines, but increased levels of CXCL1 in the periphery and in astrocytes. Oligodendrocyte CXCR2 binds CXCL1 and has been implicated in normal myelination. In addition, despite extensive immune cell accumulation in the CNS, all ERβ ligands promoted extensive remyelination in mice at peak EAE. This finding highlights a component of the mechanism by which ERβ ligands mediate remyelination. Hence, interplay between the immune system and central nervous system may be responsible for the remyelinating effects of ERβ ligands. Our findings of potential neuroprotective benefits arising from the presence of CXCL1 could have implications for improved therapies for multiple sclerosis.

Induced CNS expression of CXCL1 augments neurologic disease in a murine model of multiple sclerosis via enhanced neutrophil recruitment

Increasing evidence points to an important role for neutrophils in participating in the pathogenesis of the human demyelinating disease MS and the animal model EAE. Therefore, a better understanding of the signals controlling migration of neutrophils as well as evaluating the role of these cells in demyelination is important to define cellular components that contribute to disease in MS patients. In this study, we examined the functional role of the chemokine CXCL1 in contributing to neuroinflammation and demyelination in EAE. Using transgenic mice in which expression of CXCL1 is under the control of a tetracycline‐inducible promoter active within glial fibrillary acidic protein‐positive cells, we have shown that sustained CXCL1 expression within the CNS increased the severity of clinical and histologic disease that was independent of an increase in the frequency of encephalitogenic Th1 and Th17 cells. Rather, disease was associated with enhanced recruitment of CD11b⁺Ly6G⁺ neutrophils into the spinal cord. Targeting neutrophils resulted in a reduction in demyelination arguing for a role for these cells in myelin damage. Collectively, these findings emphasize that CXCL1‐mediated attraction of neutrophils into the CNS augments demyelination suggesting that this signaling pathway may offer new targets for therapeutic intervention.

BCG and Adverse Events in the Context of Leprosy

Background

Notwithstanding its beneficial immunoprophylactic outcomes regarding leprosy and childhood TB, BCG vaccination may cause adverse events, particularly of the skin. However, this local hyper-immune reactivity cannot be predicted before vaccination, nor is its association with protection against leprosy known. In this study we investigated the occurrence of adverse events after BCG (re)vaccination in contacts of leprosy patients and analyzed whether the concomitant systemic anti-mycobacterial immunity was associated with these skin manifestations.

Methods

Within a randomized controlled BCG vaccination trial in Bangladesh, 14,828 contacts of newly diagnosed leprosy patients received BCG vaccination between 2012 and 2017 and were examined for adverse events 8 to 12 weeks post-vaccination. From a selection of vaccinated contacts, venous blood was obtained at follow-up examination and stimulated with Mycobacterium leprae (M. leprae) antigens in overnight whole-blood assays (WBA). M. leprae phenolic glycolipid-I-specific antibodies and 32 cytokines were determined in WBAs of 13 individuals with and 13 individuals without adverse events after vaccination.

Results

Out of the 14,828 contacts who received BCG vaccination, 50 (0.34%) presented with adverse events, mainly (80%) consisting of skin ulcers. Based on the presence of BCG scars, 30 of these contacts (60%) had received BCG in this study as a booster vaccination. Similar to the pathological T-cell immunity observed for tuberculoid leprosy patients, contacts with adverse events at the site of BCG vaccination showed elevated IFN-γ levels in response to M. leprae-specific proteins in WBA. However, decreased levels of sCD40L in serum and GRO (CXCL1) in response to M. leprae simultaneously indicated less T-cell regulation in these individuals, potentially causing uncontrolled T-cell immunity damaging the skin.

Conclusion

Skin complications after BCG vaccination present surrogate markers for protective immunity against leprosy, but also indicate a higher risk of developing tuberculoid leprosy.

Clinical Trial Registration

Netherlands Trial Register: NTR3087.

Effects of Keratinocyte-Derived Cytokine (CXCL-1) on the Development of Theiler's Virus-Induced Demyelinating Disease

CXCL-1, also called keratinocyte-derived cytokine (KC), is a predominant chemokine produced in glial cells upon infection with Theiler's murine encephalomyelitis virus (TMEV). In this study, we assessed the role of KC in the development of TMEV-induced demyelinating disease by utilizing polyclonal anti-KC antibodies as well as KC-expressing recombinant TMEV. Our results indicate that the level of KC produced after infection with TMEV or stimulation with various TLRs is significantly higher in various cells from susceptible SJL mice compared to those in cells from resistant B6 mice. SJL mice treated with rabbit anti-KC antibodies displayed accelerated development of TMEV-induced demyelinating disease, elevated viral loads in the CNS and decreased antiviral T cell responses. In addition, infection of susceptible SJL mice with recombinant KC-TMEV produced biologically active KC, which resulted in the accelerated pathogenesis of demyelinating disease and elevated T cell responses to viral antigens compared to mice infected with control recombinant HEL-TMEV. These results strongly suggest that both the lack of KC during TMEV infection and the excessive presence of the chemokine promote the pathogenesis of demyelinating disease. Therefore, a balance in the level of KC during TMEV infection appears to be critically important in controlling the pathogenesis of demyelinating disease.

In vivo immune interactions of multipotent stromal cells underlie their long-lasting pain-relieving effect

Systemic infusion of bone marrow stromal cells (BMSCs), a major type of multipotent stromal cells, produces pain relief (antihyperalgesia) that lasts for months. However, studies have shown that the majority of BMSCs are trapped in the lungs immediately after intravenous infusion and their survival time in the host is inconsistent with their lengthy antihyperalgesia. Here we show that long-lasting antihyperalgesia produced by BMSCs required their chemotactic factors such as CCL4 and CCR2, the integrations with the monocytes/macrophages population, and BMSC-induced monocyte CXCL1. The activation of central mu-opioid receptors related to CXCL1-CXCR2 signaling plays an important role in BMSC-produced antihyperalgesia. Our findings suggest that the maintenance of antihypergesia can be achieved by immune regulation without actual engraftment of BMSCs. In the capacity of therapeutic use of BMSCs other than structural repair and replacement, more attention should be directed to their role as immune modulators and subsequent alterations in the immune system.

MyD88 contribution to ocular surface homeostasis

The cornea must maintain homeostasis, enabling rapid response to injury and microbial insult, to protect the eye from insult and infection. Toll-like receptors (TLRs) are critical to this innate immune response through the recognition and response to pathogens. Myeloid differentiation primary response (MyD88) is a key signaling molecule necessary for Toll-like receptor (TLR) and interleukin-1 receptor (IL-1R)-mediated immune defense and has been shown to be necessary for corneal defense during infection. Here, we examined the intrinsic role of TLR signaling in ocular surface tissues by determining baseline levels of inflammatory mediators, the response to mechanical stimuli, and corneal infection in MyD88-deficient mice (MyD88^-/-). In addition, cytokine, chemokine, and matrix metalloproteinase (MMP) expression was determined in ocular surface cells exposed to a panel of TLR agonists. Compared to wild-type (WT) animals, MyD88^-/- mice expressed lower MMP-9 levels in the cornea and conjunctiva. Corneal IL-1α, TNFα, and conjunctival IL-1α, IL-2, IL-6, and IL-9 levels were also significantly reduced. Additionally, CXCL1 and RANTES expression was lower in both MyD88^-/- tissues compared to WT and IL-1R^-/- mice. Interestingly, MyD88^-/- mice had lower corneal sensitivities (1.01±0.31 gm/mm²) than both WT (0.59±0.16 gm/mm²) and IL-1R^-/- (0.52±0.08 gm/mm²). Following Pseudomonas aeruginosa challenge, MyD88^-/- mice had better clinical scores (0.5±0.0) compared to IL-1R^-/- (1.5±0.6) and WT (2.3±0.3) animals, but had significantly more corneal bacterial isolates. However, no signs of infection were detected in inoculated uninjured corneas from either MyD88 or IL-1R-deficient mice. This work furthers our understanding of the importance of TLR signaling in corneal defense and immune homeostasis, showing that a lack of MyD88 may compromise the baseline innate response to insult.

Early postnatal exposure to intermittent hypoxia in rodents is proinflammatory, impairs white matter integrity, and alters brain metabolism

BackgroundPreterm infants are frequently exposed to intermittent hypoxia (IH) associated with apnea and periodic breathing that may result in inflammation and brain injury that later manifests as cognitive and executive function deficits. We used a rodent model to determine whether early postnatal exposure to IH would result in inflammation and brain injury.MethodsRat pups were exposed to IH from P2 to P12. Control animals were exposed to room air. Cytokines were analyzed in plasma and brain tissue at P13 and P18. At P20-P22, diffusion tensor imaging (DTI) and magnetic resonance spectroscopy (MRS) were performed.ResultsPups exposed to IH had increased plasma Gro/CXCL1 and cerebellar IFN-γ and IL-1β at P13, and brainstem enolase at P18. DTI showed a decrease in FA and AD in the corpus callosum (CC) and cingulate gyrus, and an increase in RD in the CC. MRS revealed decreases in NAA/Cho, Cr, Tau/Cr, and Gly/Cr; increases in TCho and GPC in the brainstem; and decreases in NAA/Cho in the hippocampus.ConclusionsWe conclude that early postnatal exposure to IH, similar in magnitude to that experienced in human preterm infants, is associated with evidence for proinflammatory changes, decreases in white matter integrity, and metabolic changes consistent with hypoxia.

What's Normal? Immune Profiling of Human Milk from Healthy Women Living in Different Geographical and Socioeconomic Settings

Human milk provides a very wide range of nutrients and bioactive components, including immune factors, human milk oligosaccharides, and a commensal microbiota. These factors are essential for interconnected processes including immunity programming and the development of a normal infant gastrointestinal microbiome. Newborn immune protection mostly relies on maternal immune factors provided through milk. However, studies dealing with an in-depth profiling of the different immune compounds present in human milk and with the assessment of their natural variation in healthy women from different populations are scarce. In this context, the objective of this work was the detection and quantification of a wide array of immune compounds, including innate immunity factors (IL1β, IL6, IL12, INFγ, TNFα), acquired immunity factors (IL2, IL4, IL10, IL13, IL17), chemokines (IL8, Groα, MCP1, MIP1β), growth factors [IL5, IL7, epidermal growth factor (EGF), granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, TGFβ2], and immunoglobulins (IgA, IgG, IgM), in milk produced by healthy women of different ethnicities living in different geographic, dietary, socioeconomic, and environmental settings. Among the analyzed factors, IgA, IgG, IgM, EGF, TGFβ2, IL7, IL8, Groα, and MIP1β were detected in all or most of the samples collected in each population and, therefore, this specific set of compounds might be considered as the "core" soluble immune factors in milk produced by healthy women worldwide. This approach may help define which immune factors are (or are not) common in milk produced by women living in various conditions, and to identify host, lifestyle, and environmental factors that affect the immunological composition of this complex biological fluid. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT02670278.

The cre-inducer doxycycline lowers cytokine and chemokine transcript levels in the gut of mice

The antibiotic doxycycline is used as an inducer of recombinase (cre)-based conditional gene knockout in mice, which is a common tool to show the effect of disrupted gene functions only in one period of a research animal's life. However, other types of such antibiotics have been shown to have a strong impact on the immune system. Here we show that in C57BL/6 mice, the most commonly applied strain for genetic modification, doxycycline treatment lowered transcription of the genes Il1b, Il10, Il18, Tnf, Cxcl1, and Cxcl2 in the ileum, and of the gene Il18 in colon. Cytokines and chemokines encoded by these genes are important in the disease expression in a range of mouse models. Although protein abundances only rarely correlate 100% to transcript levels, and the net result, therefore, may be less dramatic, it seems reasonable to be aware that a broad spectrum antibiotic, such as doxycycline, may impact the transgenic animal in ways unrelated to the activation of the gene deletion.

Attempts to Overcome Remyelination Failure: Toward Opening New Therapeutic Avenues for Multiple Sclerosis

Multiple sclerosis (MS) is a chronic immune-mediated disorder of the central nervous system that results in destruction of the myelin sheath wrapped around the axons and eventual axon degeneration. The disease is pathologically heterogeneous; however, perhaps its most frustrating aspect is the lack of efficient regenerative response for remyelination. Current treatment strategies are based on anti-inflammatory or immunomodulatory medications that have the potential to reduce the numbers of newly evolving lesions. However, therapies are still required that can repair already damaged myelin for which current treatments are not effective. A prerequisite for the development of such new treatments is understanding the reasons for insufficient endogenous repair. This review briefly summarizes the currently suggested causes of remyelination failure in MS and possible solutions.

The Subventricular Zone: A Key Player in Human Neocortical Development

One of the main characteristics of the developing brain is that all neurons and the majority of macroglia originate first in the ventricular zone (VZ), next to the lumen of the cerebral ventricles, and later on in a secondary germinal area above the VZ, the subventricular zone (SVZ). The SVZ is a transient compartment mitotically active in humans for several gestational months. It serves as a major source of cortical projection neurons as well as an additional source of glial cells and potentially some interneuron subpopulations. The SVZ is subdivided into the smaller inner (iSVZ) and the expanded outer SVZ (oSVZ). The enlargement of the SVZ and, in particular, the emergence of the oSVZ are evolutionary adaptations that were critical to the expansion and unique cellular composition of the primate cerebral cortex. In this review, we discuss the cell types and organization of the human SVZ during the first half of the 40 weeks of gestation that comprise intrauterine development. We focus on this period as it is when the bulk of neurogenesis in the human cerebral cortex takes place. We consider how the survival and fate of SVZ cells depend on environmental influences, by analyzing the results from in vitro experiments with human cortical progenitor cells. This in vitro model is a powerful tool to better understand human neocortex formation and the etiology of neurodevelopmental disorders, which in turn will facilitate the design of targeted preventive and/or therapeutic strategies.

A silver lining of neuroinflammation: Beneficial effects on myelination

Myelin accelerates action potential conduction velocity and provides essential energy support for axons. Unfortunately, myelin and myelinating cells are often vulnerable to injury or disease, resulting in myelin damage, which in turn can lead to axon dysfunction, overt pathology and neurological impairment. Inflammation is a common component of trauma and disease in both the CNS and PNS and therefore an active inflammatory response is often considered deleterious to myelin health. While inflammation can certainly damage myelin, inflammatory processes also can positively affect oligodendrocyte lineage progression, myelin debris clearance, oligodendrocyte metabolism and myelin repair. In the periphery, inflammatory cascades can also augment myelin repair, including processes initiated by infiltrating immune cells as well as by local Schwann cells. In this review, various aspects of inflammation beneficial to myelin repair are discussed and should be considered when designing or implementing anti-inflammatory therapies for CNS and PNS injury involving myelinating cells.

Subcutaneous Transplantation of Neural Precursor Cells in Experimental Autoimmune Encephalomyelitis Reduces Chemotactic Signals in the Central Nervous System

Neural precursor cell (NPC) transplantation has been proposed as a therapy for multiple sclerosis (MS) and other degenerative disorders of the central nervous system (CNS). NPCs are suggested to exert immune modulation when they are transplanted in the animal model of MS, experimental autoimmune encephalomyelitis (EAE). Herein, we explore whether the effect of NPC transplantation on the clinical course and the pathological features of EAE is combined with the modulation of chemokines levels expressed in the inflamed CNS. NPCs were isolated from brains of neonatal C57/Bl6 mice and were subcutaneously administered in female mice with myelin oligodendrocyte glycoprotein (MOG)-induced EAE. Clinical signs of the disease and transcript analysis of the CNS in the acute phase were performed. In addition, the presence of inflammatory components in the spinal cord was evaluated and ex vivo proliferation of lymphocytes was measured. NPC recipients exhibited ameliorated clinical outcome and less pronounced pathological features in their spinal cord. Downregulation of chemokine mRNA levels throughout the CNS was correlated with diminished Mac-3-, CD3-, and CD4-positive cells and reduced expression levels of antigen-presenting molecules in the spinal cord. Moreover, NPC transplantation resulted in lymphocyte-related, although not splenocyte-related, peripheral immunosuppression. We conclude that NPCs ameliorated EAE potentially by modulating the levels of chemokines expressed in the inflamed CNS, thus resulting in the impaired recruitment of immune cells. These findings further contribute to the better understanding of NPCs' immunomodulatory properties in neuroinflammatory disorders, and may lead to faster translation into potential clinical use.

SIGNIFICANCE

Endogenous neural precursor cells of the central nervous system are able to migrate and differentiate toward mature cells to repair an injury. There is increasing evidence that autologous transplantation of these cells in experimental autoimmune encephalomyelitis, the animal model of multiple sclerosis, may have a beneficial effect on the disease process. Several mechanisms have been proposed-among them, the potentiation of endogenous precursor cell differentiation of the central nervous system and the modulation of demyelinating and neurodegenerative immune-mediated processes. This article provides evidence of interference in immune signaling within the central nervous system as a potential mechanism underlying the immunomodulatory properties of transplanted neural precursor cells.

Rosuvastatin enhances anti-inflammatory and inhibits pro-inflammatory functions in cultured microglial cells

Microglial activation results in profound morphological, functional and gene expression changes that affect the pro- and anti-inflammatory mechanisms of these cells. Although statins have beneficial effects on inflammation, they have not been thoroughly investigated for their ability to affect microglial functions. Therefore the effects of rosuvastatin, one of the most commonly prescribed drugs in cardiovascular therapy, either alone or in combination with bacterial lipopolysaccharide (LPS), were profiled in pure microglial cultures derived from the forebrains of 18-day-old rat embryos. To reveal the effects of rosuvastatin on a number of pro- and anti-inflammatory mechanisms, we performed morphometric, functional and gene expression studies relating to cell adhesion and proliferation, phagocytosis, pro- and anti-inflammatory cytokine (IL-1β, tumor necrosis factor α (TNF-α) and IL-10, respectively) production, and the expression of various inflammation-related genes, including those related to the above morphological parameters and cellular functions. We found that microglia could be an important therapeutic target of rosuvastatin. In unchallenged (control) microglia, rosuvastatin inhibited proliferation and cell adhesion, but promoted microspike formation and elevated the expression of certain anti-inflammatory genes (Cxcl1, Ccl5, Mbl2), while phagocytosis or pro- and anti-inflammatory cytokine production were unaffected. Moreover, rosuvastatin markedly inhibited microglial activation in LPS-challenged cells by affecting both their morphology and functions as it inhibited LPS-elicited phagocytosis and inhibited pro-inflammatory cytokine (IL-1β, TNF-α) production, concomitantly increasing the level of IL-10, an anti-inflammatory cytokine. Finally, rosuvastatin beneficially and differentially affected the expression of a number of inflammation-related genes in LPS-challenged cells by inhibiting numerous pro-inflammatory and stimulating several anti-inflammatory genes. Since the microglia could elicit pro-inflammatory responses leading to neurodegeneration, it is important to attenuate such mechanisms and promote anti-inflammatory properties, and develop prophylactic therapies. By beneficially regulating both pro- and anti-inflammatory microglial functions, rosuvastatin may be considered as a prophylactic agent in the prevention of inflammation-related neurological disorders.

Systematic Review of the Neurobiological Relevance of Chemokines to Psychiatric Disorders

Psychiatric disorders are highly prevalent and disabling conditions of increasing public health relevance. Much recent research has focused on the role of cytokines in the pathophysiology of psychiatric disorders; however, the related family of immune proteins designated chemokines has been relatively neglected. Chemokines were originally identified as having chemotactic function on immune cells; however, recent evidence has begun to elucidate novel, brain-specific functions of these proteins of relevance to the mechanisms of psychiatric disorders. A systematic review of both human and animal literature in the PubMed and Google Scholar databases was undertaken. After application of all inclusion and exclusion criteria, 157 references were remained for the review. Some early mechanistic evidence does associate select chemokines with the neurobiological processes, including neurogenesis, modulation of the neuroinflammatory response, regulation of the hypothalamus–pituitary–adrenal axis, and modulation of neurotransmitter systems. This early evidence however does not clearly demonstrate any specificity for a certain psychiatric disorder, but is primarily relevant to mechanisms which are shared across disorders. Notable exceptions include CCL11 that has recently been shown to impair hippocampal function in aging – of distinct relevance to Alzheimer’s disease and depression in the elderly, and pre-natal exposure to CXCL8 that may disrupt early neurodevelopmental periods predisposing to schizophrenia. Pro-inflammatory chemokines, such as CCL2, CCL7, CCL8, CCL12, and CCL13, have been shown to drive chemotaxis of pro-inflammatory cells to the inflamed or injured CNS. Likewise, CX3CL has been implicated in promoting glial cells activation, pro-inflammatory cytokines secretion, expression of ICAM-1, and recruitment of CD4+ T-cells into the CNS during neuroinflammatory processes. With further translational research, chemokines may present novel diagnostic and/or therapeutic targets in psychiatric disorders.

Alterations in Brain Inflammation, Synaptic Proteins, and Adult Hippocampal Neurogenesis during Epileptogenesis in Mice Lacking Synapsin2

Synapsins are pre-synaptic vesicle-associated proteins linked to the pathogenesis of epilepsy through genetic association studies in humans. Deletion of synapsins causes an excitatory/inhibitory imbalance, exemplified by the epileptic phenotype of synapsin knockout mice. These mice develop handling-induced tonic-clonic seizures starting at the age of about 3 months. Hence, they provide an opportunity to study epileptogenic alterations in a temporally controlled manner. Here, we evaluated brain inflammation, synaptic protein expression, and adult hippocampal neurogenesis in the epileptogenic (1 and 2 months of age) and tonic-clonic (3.5-4 months) phase of synapsin 2 knockout mice using immunohistochemical and biochemical assays. In the epileptogenic phase, region-specific microglial activation was evident, accompanied by an increase in the chemokine receptor CX3CR1, interleukin-6, and tumor necrosis factor-α, and a decrease in chemokine keratinocyte chemoattractant/ growth-related oncogene. Both post-synaptic density-95 and gephyrin, scaffolding proteins at excitatory and inhibitory synapses, respectively, showed a significant up-regulation primarily in the cortex. Furthermore, we observed an increase in the inhibitory adhesion molecules neuroligin-2 and neurofascin and potassium chloride co-transporter KCC2. Decreased expression of γ-aminobutyric acid receptor-δ subunit and cholecystokinin was also evident. Surprisingly, hippocampal neurogenesis was reduced in the epileptogenic phase. Taken together, we report molecular alterations in brain inflammation and excitatory/inhibitory balance that could serve as potential targets for therapeutics and diagnostic biomarkers. In addition, the regional differences in brain inflammation and synaptic protein expression indicate an epileptogenic zone from where the generalized seizures in synapsin 2 knockout mice may be initiated or spread.

The secretome of apoptotic human peripheral blood mononuclear cells attenuates secondary damage following spinal cord injury in rats

After spinal cord injury (SCI), secondary damage caused by oxidative stress, inflammation, and ischemia leads to neurological deterioration. In recent years, therapeutic approaches to trauma have focused on modulating this secondary cascade. There is increasing evidence that the success of cell-based SCI therapy is due mainly to secreted factors rather than to cell implantation per se. This study investigated peripheral blood mononuclear cells as a source of factors for secretome- (MNC-secretome-) based therapy. Specifically, we investigated whether MNC-secretome had therapeutic effects in a rat SCI contusion model and its possible underlying mechanisms. Rats treated with MNC-secretome showed substantially improved functional recovery, attenuated cavity formation, and reduced acute axonal injury compared to control animals. Histological evaluation revealed higher vascular density in the spinal cords of treated animals. Immunohistochemistry showed that MNC-secretome treatment increased the recruitment of CD68(+) cells with concomitant reduction of oxidative stress as reflected by lower expression of inducible nitric oxide synthase. Notably, MNC-secretome showed angiogenic properties ex vivo in aortic rings and spinal cord tissue, and experiments showed that the angiogenic potential of MNC-secretome may be regulated by CXCL-1 upregulation in vivo. Moreover, systemic application of MNC-secretome activated the ERK1/2 pathway in the spinal cord. Taken together, these results indicate that factors in MNC-secretome can mitigate the pathophysiological processes of secondary damage after SCI and improve functional outcomes in rats.

The cerebrospinal fluid cytokine signature of multiple sclerosis: a homogenous response that does not conform to the Th1/Th2/Th17 convention

In this cross-sectional study, we wanted to identify key cytokines characteristic of different stages of multiple sclerosis (MS). To this end, cerebrospinal fluid from patients with MS was investigated with a multiplexed fluorescent bead-based immunoassay. In total 43 cytokines were assessed and related to clinical and imaging data. Increased levels of CCL22, CXCL10 and sCD40L characterized relapsing-remitting MS patients with the presence of gadolinium-enhancing lesions; decreased CCL2 and increased CXCL1 and CCL5 were typical of relapsing-remitting MS patients irrespectively of the presence of gadolinium-enhancing lesions. These homogenous patterns of cytokine activation do not conform to conventional Th1/Th2/Th17 responses.

Promoting remyelination in multiple sclerosis-recent advances

We review the current state of knowledge of remyelination in multiple sclerosis (MS), concentrating on advances in the understanding of the pathology and the regenerative response, and we summarise progress on the development of new therapies to enhance remyelination aimed at reducing progressive accumulation of disability in MS. We discuss key target pathways identified in experimental models, as although most identified targets have not yet progressed to the stage of being tested in human clinical trials, they may provide treatment strategies for demyelinating diseases in the future. Finally, we discuss some of the problems associated with testing this class of drugs, where they might fit into the therapeutic arsenal and the gaps in our knowledge.