Optimizing NK-92 serial killers: gamma irradiation, CD95/Fas-ligation, and NK or LAK attack limit cytotoxic efficacy.

BACKGROUND: The NK cell line NK-92 and its genetically modified variants are receiving attention as immunotherapies to treat a range of malignancies. However, since NK-92 cells are themselves tumors, they require irradiation prior to transfer and are potentially susceptible to attack by patients' immune systems. Here, we investigated NK-92 cell-mediated serial killing for the effects of gamma-irradiation and ligation of the death receptor Fas (CD95), and NK-92 cell susceptibility to attack by activated primary blood NK cells. METHODS: To evaluate serial killing, we used 51Cr-release assays with low NK-92 effector cell to target Raji, Daudi or K562 tumor cell (E:T) ratios to determine killing frequencies at 2-, 4-, 6-, and 8-h. RESULTS: NK-92 cells were able to kill up to 14 Raji cells per NK-92 cell in 8 h. NK-92 cells retained high cytotoxic activity immediately after irradiation with 10 Gy but the cells surviving irradiation lost > 50% activity 1 day after irradiation. Despite high expression of CD95, NK-92 cells maintained their viability following overnight Fas/CD95-ligation but lost some cytotoxic activity. However, 1 day after irradiation, NK-92 cells were more susceptible to Fas ligation, resulting in decreased cytotoxic activity of the cells surviving irradiation. Irradiated NK-92 cells were also susceptible to killing by both unstimulated and IL-2 activated primary NK cells (LAK). In contrast, non-irradiated NK-92 cells were more resistant to attack by NK and LAK cells. CONCLUSIONS: Irradiation is deleterious to both the survival and cytotoxicity mediated by NK-92 cells and renders the NK-92 cells susceptible to Fas-initiated death and death initiated by primary blood NK cells. Therefore, replacement of irradiation as an antiproliferative pretreatment and genetic deletion of Fas and/or NK activation ligands from adoptively transferred cell lines are indicated as new approaches to increase therapeutic efficacy.

Mucosal Immunity and the Gut-Microbiota-Brain-Axis in Neuroimmune Disease.

Recent advances in next-generation sequencing (NGS) technologies have opened the door to a wellspring of information regarding the composition of the gut microbiota. Leveraging NGS technology, early metagenomic studies revealed that several diseases, such as Alzheimer's disease, Parkinson's disease, autism, and myalgic encephalomyelitis, are characterized by alterations in the diversity of gut-associated microbes. More recently, interest has shifted toward understanding how these microbes impact their host, with a special emphasis on their interactions with the brain. Such interactions typically occur either systemically, through the production of small molecules in the gut that are released into circulation, or through signaling via the vagus nerves which directly connect the enteric nervous system to the central nervous system. Collectively, this system of communication is now commonly referred to as the gut-microbiota-brain axis. While equally important, little attention has focused on the causes of the alterations in the composition of gut microbiota. Although several factors can contribute, mucosal immunity plays a significant role in shaping the microbiota in both healthy individuals and in association with several diseases. The purpose of this review is to provide a brief overview of the components of mucosal immunity that impact the gut microbiota and then discuss how altered immunological conditions may shape the gut microbiota and consequently affect neuroimmune diseases, using a select group of common neuroimmune diseases as examples.

Photocytotoxicity of Oligothienyl-Functionalized Chelates That Sensitize LnIII Luminescence and Generate 1 O2.

Three new compounds containing a heptadentate lanthanide (LnIII ) ion chelator functionalized with oligothiophenes, nThept(COOH)4 (n=1, 2, or 3), were isolated. Their LnIII complexes not only display the characteristic metal-centered emission in the visible or near-infrared (NIR) but also generate singlet oxygen (1 O2 ). Luminescence efficiencies (ϕLn ) for [Eu1Thept(COO)4 ]- and [Eu2Thept(COO)4 ]- are ϕEu =3 % and 0.5 % in TRIS buffer and 33 % and 3 % in 95 % ethanol, respectively. 3Thept(COO)4 4- does not sensitize EuIII emission due to its low-lying triplet state. Near infra-red (NIR) luminescence is observed for all NIR-emitting LnIII and ligands with efficiencies of ϕYb =0.002 %, 0.005 % and 0.04 % for [YbnThept(COO)4 ]- (n=1, 2, or 3), and ϕNd =0.0007 %, 0.002 % and 0.02 % for [NdnThept(COO)4 ]- (n=1, 2, or 3) in TRIS buffer. In 95 % ethanol, quantum yields of NIR luminescence increase and are ϕYb =0.5 %, 0.31 % and 0.05 % for [YbnThept(COO)4 ]- (n=1, 2, or 3), and ϕNd =0.40 %, 0.45 % and 0.12 % for [NdnThept(COO)4 ]- (n=1, 2, or 3). All complexes are capable of generating 1 O2 in 95 % ethanol with ϕ1Ο2 efficiencies which range from 2 % to 29 %. These complexes are toxic to HeLa cells when irradiated with UV light (λexc =365 nm) for two minutes. IC50 values for the LnIII complexes are in the range 15.2-16.2 µm; the most potent compound is [Nd2Thept(COO)4 ]- . The cell death mechanisms are further explored using an Annexin V-propidium iodide assay which suggests that cell death occurs through both apoptosis and necrosis.

Single-nucleotide polymorphisms in a cohort of significantly obese women without cardiometabolic diseases.

BACKGROUND/OBJECTIVES: Obesity is an important risk factor for the development of diseases such as diabetes mellitus, hypertension, and dyslipidemia; however, a small number of individuals with long-standing obesity do not present with these cardiometabolic diseases. Such individuals are referred to as metabolically healthy obese (MHO) and potentially represent a subgroup of the general population with a protective genetic predisposition to obesity-related diseases. We hypothesized that individuals who were metabolically healthy, but significantly obese (BMI ≥ 35 kg/m2) would represent a highly homogenous subgroup, with which to investigate potential genetic associations to obesity. We further hypothesized that such a cohort may lend itself well to investigate potential genotypes that are protective with respect to the development of cardiometabolic disease. SUBJECTS/METHODS: In the present study, we implemented this novel selection strategy by screening 892 individuals diagnosed as Class 2 or Class 3 obese and identified 38 who presented no manifestations of cardiometabolic disease. We then assessed these subjects for single-nucleotide polymorphisms (SNPs) that associated with this phenotype. RESULTS: Our analysis identified 89 SNPs that reach statistical significance (p < 1 × 10-5), some of which are associated with genes of biological pathways that influences dietary behavior; others are associated with genes previously linked to obesity and cardiometabolic disease as well as neuroimmune disease. This study, to the best of our knowledge, represents the first genetic screening of a cardiometabolically healthy, but significantly obese population.

Evaluation of four clinical laboratory parameters for the diagnosis of myalgic encephalomyelitis.

BACKGROUND: Myalgic encephalomyelitis (ME) is a complex and debilitating disease that often initially presents with flu-like symptoms, accompanied by incapacitating fatigue. Currently, there are no objective biomarkers or laboratory tests that can be used to unequivocally diagnosis ME; therefore, a diagnosis is made when a patient meets series of a costly and subjective inclusion and exclusion criteria. The purpose of the present study was to evaluate the utility of four clinical parameters in diagnosing ME. METHODS: In the present study, we utilized logistic regression and classification and regression tree analysis to conduct a retrospective investigation of four clinical laboratory in 140 ME cases and 140 healthy controls. RESULTS: Correlations between the covariates ranged between [- 0.26, 0.61]. The best model included the serum levels of the soluble form of CD14 (sCD14), serum levels of prostaglandin E2 (PGE2), and serum levels of interleukin 8, with coefficients 0.002, 0.249, and 0.005, respectively, and p-values of 3 × 10-7, 1 × 10-5, and 3 × 10-3, respectively. CONCLUSIONS: Our findings show that these parameters may help physicians in their diagnosis of ME and may additionally shed light on the pathophysiology of this disease.

Cytokine expression provides clues to the pathophysiology of Gulf War illness and myalgic encephalomyelitis.

Gulf War illness (GWI) is a chronic disease of unknown etiology characterized by persistent symptoms such as cognitive impairment, unexplained fatigue, pervasive pain, headaches, and gastrointestinal abnormalities. Current reports suggest that as many as 200,000 veterans who served in the 1990-1991 Persian Gulf War were afflicted. Several potential triggers of GWI have been proposed including chemical exposure, toxins, vaccines, and unknown infectious agents. However, a definitive cause of GWI has not been identified and a specific biological marker that can consistently delineate the disease has not been defined. Myalgic encephalomyelitis (ME) is a disease with similar and overlapping symptomology, and subjects diagnosed with GWI typically fit the diagnostic criteria for ME. For these reasons, GWI is often considered a subgroup of ME. To explore this possibility and identify immune parameters that may help to understand GWI pathophysiology, we measured 77 serum cytokines in subjects with GWI and compared these data to that of subjects with ME as well as healthy controls. Our analysis identified a group of cytokines that identified ME and GWI cases with sensitivities of 92.5% and 64.9%, respectively. The five most significant cytokines in decreasing order of importance were IL-7, IL-4, TNF-α, IL-13, and IL-17F. When delineating GWI and ME cases from healthy controls, the observed specificity was only 33.3%, suggesting that with respect to cytokine expression, GWI cases resemble control subjects to a greater extent than ME cases across a number of parameters. These results imply that serum cytokines are representative of ME pathology to a greater extent than GWI and further suggest that the two diseases have distinct immune profiles despite their overlapping symptomology.

Plasmacytoid dendritic cells, a role in neoplastic prevention and progression.

BACKGROUND: Plasmacytoid dendritic cells (pDCs) are multifunctional bone-marrow-derived immune cells that are key players in bridging the innate and adaptive immune systems. Activation of pDCs through toll-like receptor agonists has proven to be an effective treatment for some neoplastic disorders. MATERIALS AND METHODS: In this mini-review, we will explore the fascinating contribution of pDCs to neoplastic pathology and discuss their potential utilization in cancer immunotherapy. RESULTS: Current research suggests that pDCs have cytotoxic potential and can effectively induce apoptosis of tumour-derived cells lines. They are also reported to display tolerogenic function with the ability to suppress T-cell proliferation, analogous to regulatory T cells. In this capacity, they are critical in the suppression of autoimmunity but can be exploited by tumour cells to circumvent the expansion of tumour-specific T cells, thereby allowing tumours to persist. CONCLUSION: Several forms of skin cancer are successfully treated with the topical drug Imiquimod, which activates pDCs through toll-like receptor 7 engagement. Additionally, pDC-based anticancer vaccines have shown encouraging results for the treatment of melanoma in early trials. Future studies regarding the contributions of pDCs to malignancy will likely afford many opportunities for immunotherapy strategies.

Plasmacytoid dendritic cells of the gut: relevance to immunity and pathology.

Plasmacytoid dendritic cells (pDCs) are bone marrow-derived immune cells with the ability to express copious amounts of type I and III interferon (IFN) and can differentiate into antigen-presenting dendritic cells as a result of stimulation by pathogen-derived nucleic acid. These powerful combined functionalities allow pDCs to bridge the innate and adaptive immune systems resulting in a concerted pathogen response. The contribution of pDCs to gastrointestinal immunity is only now being elucidated and is proving to be a critical component in systemic immunity. This review will explore the immunology of pDCs and will discuss their involvement in human disease and tolerance with an emphasis on those in the gastrointestinal lymphoid tissue.

Differential immuno-reactivity to genomic DNA, RNA and mitochondrial DNA is associated with auto-immunity.

BACKGROUND: Circulating auto-reactive antibodies are hallmark features of auto-immune diseases, however little is known with respect to the specificity of such bio-markers. In the present study, we investigated the specificity of anti-nucleic acid antibodies in the blood of subjects with systemic lupus erythematosus (SLE) and healthy controls. METHODS: Sera from 12 SLE cases and 8 controls were evaluated for immuno-reactivity to purified RNA, DNA and mitochondrial DNA (mtDNA) by enzyme-linked immuno-sorbent assay (ELISA). RESULTS: As expected, immuno-reactivity to total nucleic acids was significantly higher in subjects with SLE when compared to healthy controls, however a clear distinction was observed among the various nucleic acid sub-types, with sera from SLE subjects displaying the greatest immuno-reactivity to RNA followed by mtDNA and then total DNA. CONCLUSION: The identification of auto-reactive antibodies can serve as highly sensitive biomarkers, although their specificity may not always allow diagnostic certainty. The knowledge that auto-antibodies in subjects with SLE display differential immuno-reactivity may help to improve existing diagnostics and may lead to a better understanding of the pathogenesis of auto-immune disorders.

Detection of Antibody-Dependent Cell-Mediated Cytotoxicity-Supporting Antibodies by NK-92-CD16A Cell Externalization of CD107a: Recognition of Antibody Afucosylation and Assay Optimization.

Antibody-dependent cell-mediated cytotoxicity (ADCC) by natural killer (NK) lymphocytes eliminates cells infected with viruses. Anti-viral ADCC requires three components: (1) antibody; (2) effector lymphocytes with the Fc-IgG receptor CD16A; and (3) viral proteins in infected cell membranes. Fc-afucosylated antibodies bind with greater affinity to CD16A than fucosylated antibodies; individuals' variation in afucosylation contributes to differences in ADCC. Current assays for afucosylated antibodies involve expensive methods. We report an improved bioassay for antibodies that supports ADCC, which encompasses afucosylation. This assay utilizes the externalization of CD107a by NK-92-CD16A cells after antibody recognition. We used anti-CD20 monoclonal antibodies, GA101 WT or glycoengineered (GE), 10% or ~50% afucosylated, and CD20-positive Raji target cells. CD107a increased detection 7-fold compared to flow cytometry to detect Raji-bound antibodies. WT and GE antibody effective concentrations (EC50s) for CD107a externalization differed by 20-fold, with afucosylated GA101-GE more detectable. The EC50s for CD107a externalization vs. 51Cr cell death were similar for NK-92-CD16A and blood NK cells. Notably, the % CD107a-positive cells were negatively correlated with dead Raji cells and were nearly undetectable at high NK:Raji ratios required for cytotoxicity. This bioassay is very sensitive and adaptable to assess anti-viral antibodies but unsuitable as a surrogate assay to monitor cell death after ADCC.

Molecular Identification and Characterization of Five Ganoderma Species from the Lower Volta River Basin of Ghana Based on Nuclear Ribosomal DNA (nrDNA) Sequences.

Ganoderma is a genus of biomedical fungus that is used in the development of numerous health products throughout the world. The Lower Volta River Basin of Ghana is an undulating land surface covered by extensive vegetation and water bodies and is rich in polypore mushrooms resembling various members of the Ganoderma genus. Despite the extensive biopharmaceutical benefits of Ganoderma spp., the isolates from the Lower Volta River Basin have not been properly characterized, thus limiting their use in the development of biotechnological products. In this study, Ganoderma spp. collected from the Lower Volta River Basin were genetically analyzed using the nuclear ribosomal sequences, the internal transcribed spacer 2 (ITS 2), the complete internal transcribed spacer (ITS), and the nuclear large subunit (nLSU). Blastn search and sequence analysis revealed that the sample we coded as Ganoderma LVRB-2 belongs to G. mbrekobenum, whereas Ganoderma LVRB-1, Ganoderma LVRB-14, and Ganoderma LVRB-16 belong to the species G. enigmaticum. Our analysis further demonstrates that Ganoderma LVRB-17 belongs to the species G. resinaceum. Thus, the five samples collected in the present study were positioned in three different distinct groups, namely G. mbrekobenum, G. enigmaticum, and G. resinaceum. The current data may serve as reference points for future studies.

Decreasing the Likelihood of Multiple Organ Dysfunction Syndrome in Burn Injury with Early Antioxidant Treatment.

Major burn trauma initiates a cascade of physiological events that cause profound stress on the body, resulting in significant complications which often lead to death. An understanding of these events may afford earlier and more precise interventions which, in turn, may reduce these complications, thus, improving patient outcomes. Burn trauma is associated with numerous inflammatory events that result in the release of free radicals, which promote oxidative stress and subsequent tissue damage. These mass-inflammatory events affect the body systemically, leading to several detrimental responses including complement activation, excessive histamine release, decrease in blood pressure, release of reactive oxygen species, and ultimately multiple organ dysfunction syndrome (MODS). However, recent studies conducted on the use of antioxidants as a part of a burn treatment protocol have shown promising results. In this review, we will discuss the current research and advancements in the treatment of burn trauma with the use of antioxidants, and how the early administration of antioxidant can possibly reduce the risk of developing MODS.

Genome-Wide Identification of Rare and Common Variants Driving Triglyceride Levels in a Nevada Population.

Clinical conditions correlated with elevated triglyceride levels are well-known: coronary heart disease, hypertension, and diabetes. Underlying genetic and phenotypic mechanisms are not fully understood, partially due to lack of coordinated genotypic-phenotypic data. Here we use a subset of the Healthy Nevada Project, a population of 9,183 sequenced participants with longitudinal electronic health records to examine consequences of altered triglyceride levels. Specifically, Healthy Nevada Project participants sequenced by the Helix Exome+ platform were cross-referenced to their electronic medical records to identify: (1) rare and common single-variant genome-wide associations; (2) gene-based associations using a Sequence Kernel Association Test; (3) phenome-wide associations with triglyceride levels; and (4) pleiotropic variants linked to triglyceride levels. The study identified 549 significant single-variant associations (p < 8.75 × 10-9), many in chromosome 11's triglyceride hotspot: ZPR1, BUD13, APOC3, APOA5. A well-known protective loss-of-function variant in APOC3 (R19X) was associated with a 51% decrease in triglyceride levels in the cohort. Sixteen gene-based triglyceride associations were identified; six of these genes surprisingly did not include a single variant with significant associations. Results at the variant and gene level were validated with the UK Biobank. The combination of a single-variant genome-wide association, a gene-based association method, and phenome wide-association studies identified rare and common variants, genes, and phenotypes associated with elevated triglyceride levels, some of which may have been overlooked with standard approaches.

Photocytotoxicity of Thiophene- and Bithiophene-Dipicolinato Luminescent Lanthanide Complexes.

New thiophene-dipicolinato-based compounds, K2nTdpa (n = 1, 2), were isolated. Their anions are sensitizers of lanthanide ion (LnIII) luminescence and singlet oxygen generation (1O2). Emission in the visible and near-infrared regions was observed for the LnIII complexes with efficiencies (ϕLn) ϕEu = 33% and ϕYb = 0.31% for 1Tdpa2- and ϕYb = 0.07% for 2Tdpa2-. The latter does not sensitize EuIII emission. Fluorescence imaging of HeLa live cells incubated with K3[Eu(1Tdpa)3] indicates that the complex permeates the cell membrane and localizes in the mitochondria. All complexes generate 1O2 in solution with efficiencies (ϕO12) as high as 13 and 23% for the GdIII complexes of 1Tdpa2- and 2Tdpa2-, respectively. [Ln(nTdpa)3]3- (n = 1, 2) are phototoxic to HeLa cells when irradiated with UV light with IC50 values as low as 4.2 µM for [Gd(2Tdpa)3]3- and 91.8 µM for [Eu(1Tdpa)3]3-. Flow cytometric analyses indicate both apoptotic and necrotic cell death pathways.

A Comprehensive Genome-Wide and Phenome-Wide Examination of BMI and Obesity in a Northern Nevadan Cohort.

The aggregation of Electronic Health Records (EHR) and personalized genetics leads to powerful discoveries relevant to population health. Here we perform genome-wide association studies (GWAS) and accompanying phenome-wide association studies (PheWAS) to validate phenotype-genotype associations of BMI, and to a greater extent, severe Class 2 obesity, using comprehensive diagnostic and clinical data from the EHR database of our cohort. Three GWASs of 500,000 variants on the Illumina platform of 6,645 Healthy Nevada participants identified several published and novel variants that affect BMI and obesity. Each GWAS was followed with two independent PheWASs to examine associations between extensive phenotypes (incidence of diagnoses, condition, or disease), significant SNPs, BMI, and incidence of extreme obesity. The first GWAS examines associations with BMI in a cohort with no type 2 diabetics, focusing exclusively on BMI. The second GWAS examines associations with BMI in a cohort that includes type 2 diabetics. In the second GWAS, type 2 diabetes is a comorbidity, and thus becomes a covariate in the statistical model. The intersection of significant variants of these two studies is surprising. The third GWAS is a case vs. control study, with cases defined as extremely obese (Class 2 or 3 obesity), and controls defined as participants with BMI between 18.5 and 25. This last GWAS identifies strong associations with extreme obesity, including established variants in the FTO and NEGR1 genes, as well as loci not yet linked to obesity. The PheWASs validate published associations between BMI and extreme obesity and incidence of specific diagnoses and conditions, yet also highlight novel links. This study emphasizes the importance of our extensive longitudinal EHR database to validate known associations and identify putative novel links with BMI and obesity.

Nutritional modulation of the intestinal microbiota; future opportunities for the prevention and treatment of neuroimmune and neuroinflammatory disease.

The gut-brain axis refers to the bidirectional communication between the enteric nervous system and the central nervous system. Mounting evidence supports the premise that the intestinal microbiota plays a pivotal role in its function and has led to the more common and perhaps more accurate term gut-microbiota-brain axis. Numerous studies have identified associations between an altered microbiome and neuroimmune and neuroinflammatory diseases. In most cases, it is unknown if these associations are cause or effect; notwithstanding, maintaining or restoring homeostasis of the microbiota may represent future opportunities when treating or preventing these diseases. In recent years, several studies have identified the diet as a primary contributing factor in shaping the composition of the gut microbiota and, in turn, the mucosal and systemic immune systems. In this review, we will discuss the potential opportunities and challenges with respect to modifying and shaping the microbiota through diet and nutrition in order to treat or prevent neuroimmune and neuroinflammatory disease.

Humoral Immunity Profiling of Subjects with Myalgic Encephalomyelitis Using a Random Peptide Microarray Differentiates Cases from Controls with High Specificity and Sensitivity.

Myalgic encephalomyelitis (ME) is a complex, heterogeneous illness of unknown etiology. The search for biomarkers that can delineate cases from controls is one of the most active areas of ME research; however, little progress has been made in achieving this goal. In contrast to identifying biomarkers that are directly involved in the pathological process, an immunosignature identifies antibodies raised to proteins expressed during, and potentially involved in, the pathological process. Although these proteins might be unknown, it is possible to detect antibodies that react to these proteins using random peptide arrays. In the present study, we probe a custom 125,000 random 12-mer peptide microarray with sera from 21 ME cases and 21 controls from the USA and Europe and used these data to develop a diagnostic signature. We further used these peptide sequences to potentially uncover the naturally occurring candidate antigens to which these antibodies may specifically react with in vivo. Our analysis revealed a subset of 25 peptides that distinguished cases and controls with high specificity and sensitivity. Additionally, Basic Local Alignment Search Tool (BLAST) searches suggest that these peptides primarily represent human self-antigens and endogenous retroviral sequences and, to a minor extent, viral and bacterial pathogens.

Serum Cytokine Profiles Differentiating Hemorrhagic Fever with Renal Syndrome and Hantavirus Pulmonary Syndrome.

Hantavirus infection is an acute zoonosis that clinically manifests in two primary forms, hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). HFRS is endemic in Europe and Russia, where the mild form of the disease is prevalent in the Tatarstan region. HPS is endemic in Argentina, as well as other countries of North and South American. HFRS and HPS are usually acquired via the upper respiratory tract by inhalation of virus-contaminated aerosol. Although the pathogenesis of HFRS and HPS remains largely unknown, postmortem tissue studies have identified endothelial cells as the primary target of infection. Importantly, cell damage due to virus replication, or subsequent tissue repair, has not been documented. Since no single factor has been identified that explains the complexity of HFRS or HPS pathogenesis, it has been suggested that a cytokine storm may play a crucial role in the manifestation of both diseases. In order to identify potential serological markers that distinguish HFRS and HPS, serum samples collected during early and late phases of the disease were analyzed for 48 analytes using multiplex magnetic bead-based assays. Overall, serum cytokine profiles associated with HPS revealed a more pro-inflammatory milieu as compared to HFRS. Furthermore, HPS was strictly characterized by the upregulation of cytokine levels, in contrast to HFRS where cases were distinguished by a dichotomy in serum cytokine levels. The severe form of hantavirus zoonosis, HPS, was characterized by the upregulation of a higher number of cytokines than HFRS (40 vs 21). In general, our analysis indicates that, although HPS and HFRS share many characteristic features, there are distinct cytokine profiles for these diseases. These profiles suggest a strong activation of an innate immune and inflammatory responses are associated with HPS, relative to HFRS, as well as a robust activation of Th1-type immune responses. Finally, the results of our analysis suggest that serum cytokines profiles of HPS and HFRS cases are consistent with the presence of extracellular matrix degradation, increased mononuclear leukocyte proliferation, and transendothelial migration.

The Skin-Brain Connection Hypothesis, Bringing Together CCL27-Mediated T-Cell Activation in the Skin and Neural Cell Damage in the Adult Brain.

Recent discovery of an association of low serum melatonin levels with relapse in multiple sclerosis (MS) opens a new horizon in understanding the pathogenesis of this disease. Skin is the main organ for sensing seasonal changes in duration of sunlight exposure. Level of melatonin production is dependent on light exposure. The molecular mechanisms connecting peripheral (skin) sensing of the light exposure and developing brain inflammation (MS) have not been investigated. We hypothesize that there is a connection between the reaction of skin to seasonal changes in sunlight exposure and the risk of MS and that seasonal changes in light exposure cause peripheral (skin) inflammation, the production of cytokines, and the subsequent inflammation of the brain. In skin of genetically predisposed individuals, cytokines attract memory cutaneous lymphocyte-associated antigen (CLA+) T lymphocytes, which then maintain local inflammation. Once inflammation is resolved, CLA+ lymphocytes return to the circulation, some of which eventually migrate to the brain. Once in the brain these lymphocytes may initiate an inflammatory response. Our observation of increased CC chemokine ligand 27 (CCL27) in MS sera supports the involvement of skin in the pathogenesis of MS. Further, the importance of our data is that CCL27 is a chemokine released by activated keratinocytes, which is upregulated in inflamed skin. We propose that high serum levels of CCL27 in MS are the result of skin inflammation due to exposure to seasonal changes in the sunlight. Future studies will determine whether CCL27 serum level correlates with seasonal changes in sunlight exposure, MS exacerbation, and skin inflammation.

Hantavirus Infection Suppresses Thrombospondin-1 Expression in Cultured Endothelial Cells in a Strain-Specific Manner.

Hantavirus infection is associated with two frequently fatal diseases in humans: Hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). The pathogenesis of hantavirus infection is complex and not fully understood; however, it is believed to involve virus-induced hyperinflammatory immune responses. Thrombospondin-1 (THBS1) is a large homotrimeric protein that plays a putative role in regulating blood homeostasis. Hyperresponsiveness to inflammatory stimuli has also been associated with defects in the THBS1 gene. Our data suggest that hantavirus infection of human umbilical cord vein endothelial cells (HUVEC) suppress the accumulation of THBS1 in the extracellular matrix. Additionally, this suppression is dependent on virus replication, implying a direct mechanism of action. Our data also imply that the pathogenic Andes and Hantaan strains inhibit THBS1 expression while the non-pathogenic Prospect Hill strain showed little inhibition. These observations suggest that a dysregulation of THBS1 may contribute to the pathogenesis of hantavirus infection.