Central Nervous System Pathophysiology Research Articles

The Role of Neutrophils in Multiple Sclerosis and Ischemic Stroke.

Inflammation plays an important role in numerous central nervous system (CNS) disorders. Its role is ambiguous-it can induce detrimental effects, as well as repair and recovery. In response to injury or infection, resident CNS cells secrete numerous factors that alter blood-brain barrier (BBB) function and recruit immune cells into the brain, like neutrophils. Their role in the pathophysiology of CNS diseases, like multiple sclerosis (MS) and stroke, is highly recognized. Neutrophils alter BBB permeability and attract other immune cells into the CNS. Previously, neutrophils were considered a homogenous population. Nowadays, it is known that various subtypes of these cells exist, which reveal proinflammatory or immunosuppressive functions. The primary goal of this review was to discuss the current knowledge regarding the important role of neutrophils in MS and stroke development and progression. As the pathogenesis of these two disorders is completely different, it gives the opportunity to get insight into diverse mechanisms of neutrophil involvement in brain pathology. Our understanding of the role of neutrophils in CNS diseases is still evolving as new aspects of their activity are being unraveled. Neutrophil plasticity adds another level to their functional complexity and their importance for CNS pathophysiology.

Astrocytes at the intersection of ageing, obesity, and neurodegeneration.

Once considered passive cells of the central nervous system (CNS), glia are now known to actively maintain the CNS parenchyma; in recent years, the evidence for glial functions in CNS physiology and pathophysiology has only grown. Astrocytes, a heterogeneous group of glial cells, play key roles in regulating the metabolic and inflammatory landscape of the CNS and have emerged as potential therapeutic targets for a variety of disorders. This review will outline astrocyte functions in the CNS in healthy ageing, obesity, and neurodegeneration, with a focus on the inflammatory responses and mitochondrial function, and will address therapeutic outlooks.

Human serum-derived α-synuclein auto-antibodies mediate NMDA receptor-dependent degeneration of CNS neurons

BackgroundPresence of autoantibodies against α-synuclein (α-syn AAb) in serum of the general population has been widely reported. That such peripheral factors may be involved in central nervous system pathophysiology was demonstrated by detection of immunoglobulins (IgGs) in cerebrospinal fluid and brain of Parkinson’s disease (PD) patients. Thus, blood-borne IgGs may reach the brain parenchyma through an impaired blood-brain barrier (BBB).FindingsThe present study aims to evaluate the patho-physiological impact of α-syn AAbs on primary brain cells, i.e., on spontaneously active neurons and on astrocytes. Exposure of neuron-astrocyte co-cultures to human serum containing α-syn AAbs mediated a dose-dependent reduction of spontaneous neuronal activity, and subsequent neurodegeneration. Removal specifically of α-syn AAbs from the serum prevented neurotoxicity, while purified, commercial antibodies against α-syn mimicked the neurodegenerative effect. Mechanistically, we found a strong calcium flux into neurons preceding α-syn AAbs-induced cell death, specifically through NMDA receptors. NMDA receptor antagonists prevented neurodegeneration upon treatment with α-syn (auto)antibodies. α-syn (auto)antibodies did not affect astrocyte survival. However, in presence of α-syn, astrocytes reacted to α-syn antibodies by secretion of the chemokine RANTES.ConclusionThese findings provide a novel basis to explain how a combination of BBB impairment and infiltration of IgGs targeting synuclein may contribute to neurodegeneration in PD and argue for caution with α-syn immunization therapies for treatment of PD.

Advanced materials and biofabrication technologies to design in vitro functional central nervous system models

Nowadays, the pathophysiology of several central nervous system (CNS) disorders is still poorly understood, making difficult the identification of efficient treatments. CNS damages, due to neurodegenerative conditions or injuries, often result in permanent neuronal dysfunctions and serious impairments of motor, sensory and cognitive capacities. Despite the many attempts of pharmaceutical research to promote neural regeneration, poor progresses have been made in effectively restoring nervous functionality. Indeed, most of the experimental drugs show limited efficacy in the clinical trials, also due to existing preclinical models’ inability in fully replicating the complexity of CNS pathophysiology. Therefore, tissue-engineered three-dimensional (3D) models are being extensively explored to develop novel representative in vitro platforms, which more carefully replicate the architecture of neural microenvironment, including both cellular and extracellular components. In this respect, 3D in vitro models are expected to be promising and comprehensive tools for investigating CNS diseases and testing new drug compounds, as they overcome some of the common limitations of traditional two-dimensional (2D) cultures. This review discusses the main challenges to be addressed in CNS modeling, analyzing the key elements involved in neural tissue engineering. Specifically, an overview of the mostly used neural cell sources and biomaterials is provided, focusing on the critical aspects to consider in selecting the appropriate components according to the application. Different methods adopted to modulate the structural and functional properties of the engineered microenvironment are also presented, aimed at fostering in vitro tissue maturation. Lastly, the latest advances in biofabrication technologies are outlined, reviewing the most recent 3D bioprinted in vitro systems and microfluidic-based 3D platforms, starting from the modeling of distinctive CNS pathophysiological mechanisms to the designing of refined and functional in vivo-like neural microtissues.

Cerebrospinal Fluid Metabolomics Identified Ongoing Analgesic Medication in Neuropathic Pain Patients.

Cerebrospinal fluid (CSF) can reasonably be hypothesized to mirror central nervous system pathophysiology in chronic pain conditions. Metabolites are small organic molecules with a low molecular weight. They are the downstream products of genes, transcripts and enzyme functions, and their levels can mirror diseased metabolic pathways. The aim of this metabolomic study was to compare the CSF of patients with chronic neuropathic pain (n = 16) to healthy controls (n = 12). Nuclear magnetic resonance spectroscopy was used for analysis of the CSF metabolome. Multivariate data analysis by projection discriminant analysis (OPLS-DA) was used to separate information from noise and minimize the multiple testing problem. The significant OPLS-DA model identified 26 features out of 215 as important for group separation (R2 = 0.70, Q2 = 0.42, p = 0.017 by CV-ANOVA; 2 components). Twenty-one out of twenty-six features were statistically significant when comparing the two groups by univariate statistics and remained significant at a false discovery rate of 10%. For six out of the top ten metabolite features, the features were absent in all healthy controls. However, these features were related to medication, mainly acetaminophen (=paracetamol), and not to pathophysiological processes. CSF metabolomics was a sensitive method to detect ongoing analgesic medication, especially acetaminophen.

A bioinformatic investigation of proteasome and autophagy expression in the central nervous system

The ubiquitin proteasome system (UPS) and autophagy lysosome pathway (ALP) are crucial in the control of protein quality. However, data regarding the relative significance of UPS and ALP in the central nervous system (CNS) are limited. In the present study, using publicly available data, we computed the quantitative expression status of UPS- and ALP-related genes and their products in the CNS as compared with that in other tissues and cells. We obtained human and mouse gene expression datasets from the reference expression dataset (RefEx) and Genevestigator (a tool for handling curated transcriptomic data from public repositories) as well as human proteomics data from the proteomics database (ProteomicsDB). The expression levels of genes and proteins in four categories—ubiquitin, proteasome, autophagy, and lysosome––in the cells and tissues were assessed. Perturbation of the gene expression by drugs was also analyzed for the four categories. Compared with that for ubiquitin, autophagy, and lysosome, gene expression for proteasome was consistently lower in the CNS of mice but was more pronounced in humans. Neural stem cells and neurons showed low proteasome gene expression as compared with embryonic stem cells. Proteomic analyses, however, did not show trends similar to those observed in the gene expression analyses. Perturbation analyses revealed that azithromycin and vitamin D3 upregulated the expression of both UPS and ALP. Gene and proteomic expression data could offer a fresh perspective on CNS pathophysiology. Our results indicate that disproportional expression of UPS and ALP might affect CNS disorders and that this imbalance might be redressed by several therapeutic candidates.

Injectable hydrogels in central nervous system: Unique and novel platforms for promoting extracellular matrix remodeling and tissue engineering.

Repairing central nervous system (CNS) is difficult due to the inability of neurons to recover after damage. A clinically acceptable treatment to promote CNS functional recovery and regeneration is currently unavailable. According to recent studies, injectable hydrogels as biodegradable scaffolds for CNS tissue engineering and regeneration have exceptionally desirable attributes. Hydrogel has a biomimetic structure similar to extracellular matrix, hence has been considered a 3D scaffold for CNS regeneration. An interesting new type of hydrogel, injectable hydrogels, can be injected into target areas with little invasiveness and imitate several aspects of CNS. Injectable hydrogels are being researched as therapeutic agents because they may imitate numerous properties of CNS tissues and hence reduce subsequent injury and regenerate neural tissue. Because of their less adverse effects and cost, easier use and implantation with less pain, and faster regeneration capacity, injectable hydrogels, are more desirable than non-injectable hydrogels. This article discusses the pathophysiology of CNS and the use of several kinds of injectable hydrogels for brain and spinal cord tissue engineering, paying particular emphasis to recent experimental studies.

Role of stimulator of interferon genes (STING) in the enteric nervous system in health and disease.

Stimulator of Interferon Genes (STING) is a crucial protein that controls the immune system's reaction to bacterial and viral infections. As a pattern-recognition receptor, STING is found in immune cells as well as in neurons and glia in the enteric nervous system (ENS). Recent studies have linked STING to the pathogenesis of several neurological disorders like multiple sclerosis (MS), Alzheimer's disease (AD), and gastrointestinal disorders, including irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), which are characterized by chronic inflammation and dysregulation of the enteric nervous system (ENS) in the digestive tract. STING plays a crucial role in the pathway that induces the production of interferon in response to viral infection in the central nervous system (CNS). A new study by Dharshika et al. in the current issue of Neurogastroenterology and Motility has demonstrated distinct roles for STING in enteric neurons and glia, namely activation of STING leads to IFN-β production in enteric neurons but not in glia and reducing STING activation in enteric glia does not modulate the severity of Dextran sulfate sodium (DSS) colitis or subsequent loss of enteric neurons. Rather, the role of STING in enteric glia is related to enhancing autophagy. STING can influence gastrointestinal motility and barrier function and therefore be involved in the pathophysiology of IBS and IBD. This mini review highlights the current knowledge of STING in the pathophysiology of CNS and gastrointestinal diseases as well as these newly uncovered roles STING in enteric neurons and glia.

Human brain organoid code of conduct

Human brain organoids are models derived from human embryonic or induced pluripotent stem cells that mimic basic cerebral microanatomy and demonstrate simple functional neuronal networks. Brain organoids have been a rapidly expanding avenue for biomedical research in general and specifically: neural development, regeneration, and central nervous system pathophysiology. However, technology replicating functional aspects of the human brain, including electrically active neural networks, requires a responsible code of conduct. In this review, we focus the discussion on intrinsic and extrinsic ethical factors associated with organoids: intrinsic considerations arise with the growing complexity of human brain organoids, including human-animal chimerism, consciousness development, and questions of where these human-like beings fall in a moral hierarchy. Extrinsic considerations explore ethics on obtainment, manufacturing, and production of sophisticated human products. In summary, a thoughtful code of conduct using human brain organoids towards the advancement of science and medicine is crucial. This article shall facilitate a structured thought process approaching the moral landscape of organoid technology.

Biotypes of Central Nervous System Complications in People Living With Human Immunodeficiency Virus (HIV): National Institute of Mental Health Perspectives on Advancing the Future of HIV Healthcare

Despite effective suppressive antiretroviral therapy, central nervous system (CNS) complications related to human immunodeficiency virus (HIV) remain a significant problem for people with HIV (PWH). Numerous studies have contributed data to define the mechanisms underlying HIV-associated CNS pathophysiology, but causality remains elusive, with no effective therapies to prevent, reduce, or reverse HIV-associated CNS complications. Multiple physiological, clinical, cognitive, behavioral, social, and environmental factors contribute to the observed heterogeneity of adverse CNS outcomes among PWH. The National Institute of Mental Health in collaboration with investigators engaged in research related to HIV associated CNS complications organized a series of meetings to review the state of the science and facilitate the development of biologically based measures to identify the phenotypic heterogeneity of CNS outcomes linked to pathophysiology (biotypes). In this article, we summarize the proceedings of these meetings and explore the precision medicine framework to identify critical factors linked to the etiopathogenesis of CNS outcomes in PWH.

Evaluation of advanced, pathophysiologic new targets for imaging of CNS.

The inadequate information about the in vivo pathological, physiological, and neurological impairments, as well as the absence of in vivo tools for assessing brain penetrance and the efficiency of newly designed drugs, has hampered the development of new techniques for the treatment for variety of new central nervous system (CNS) diseases. The searching sites such as Science Direct and PubMed were used to find out the numerous distinct tracers across 16 CNS targets including tau, synaptic vesicle glycoprotein, the adenosine 2A receptor, the phosphodiesterase enzyme PDE10A, and the purinoceptor, among others. Among the most encouraging are [18 F]FIMX for mGluR imaging, [11 C]Martinostat for Histone deacetylase, [18 F]MNI-444 for adenosine 2A imaging, [11 C]ER176 for translocator protein, and [18 F]MK-6240 for tau imaging. We also reviewed the findings for each tracer's features and potential for application in CNS pathophysiology and therapeutic evaluation investigations, including target specificity, binding efficacy, and pharmacokinetic factors. This review aims to present a current evaluation of modernpositron emission tomography tracers for CNS targets, with a focus on recent advances for targets that have newly emerged for imaging in humans.

Selenoprotein I (selenoi) as a critical enzyme in the central nervous system

Selenoprotein I (selenoi) is a unique selenocysteine (Sec)-containing protein widely expressed throughout the body. Selenoi belongs to two different protein families: the selenoproteins that are characterized by a redox reactive Sec residue and the lipid phosphotransferases that contain the highly conserved cytidine diphosphate (CDP)-alcohol phosphotransferase motif. Selenoi catalyzes the third reaction of the CDP-ethanolamine branch of the Kennedy pathway within the endoplasmic reticulum membrane. This is not a redox reaction and does not directly involve the Sec residue, making selenoi quite distinct among selenoproteins. Selenoi is also unique among lipid phosphotransferases as the only family member containing a Sec residue near its C-terminus that serves an unknown function. The reaction catalyzed by selenoi involves the transfer of the ethanolamine phosphate group from CDP-ethanolamine to one of two lipid donors, 1,2-diacylglycerol (DAG) or 1-alkyl-2-acylglycerol (AAG), to produce PE or plasmanyl PE, respectively. Plasmanyl PE is subsequently converted to plasmenyl PE by plasmanylethanolamine desaturase. Both PE and plasmenyl PE are critical phospholipids in the central nervous system (CNS), as demonstrated through clinical studies involving SELENOI mutations as well as studies in cell lines and mice. Deletion of SELENOI in mice is embryonic lethal, while loss-of-function mutations in the human SELENOI gene have been found in rare cases leading to a form of hereditary spastic paraplegia (HSP). HSP is an upper motor disease characterized by spasticity of the lower limbs, which is often manifested with other symptoms such as impaired vision/hearing, ataxia, cognitive/intellectual impairment, and seizures. This article will summarize the current understanding of selenoi as a metabolic enzyme and discuss its role in the CNS physiology and pathophysiology.

NK cells in the brain: implications for brain tumor development and therapy.

Natural killer (NK) cells are innate lymphoid cells with robust antitumor functions rendering them promising therapeutic tools against malignancies. Despite constituting a minor fraction of the immune cells infiltrating tumors in the brain, insights into their role in central nervous system (CNS) pathophysiology are emerging. The challenges posed by a profoundly immunosuppressive microenvironment as well as by tumor resistance mechanisms necessitate exploring avenues to enhance the therapeutic potential of NK cells in both primary and metastatic brain malignancies. In this review, we summarize the role of NK cells in the pathogenesis of tumors in the brain and discuss the avenues investigated to harness their anticancer effects against primary and metastatic CNS tumors, including sources of therapeutic NK cells, combinations with other treatments, and novel engineering approaches for augmenting their cytotoxicity. We also highlight relevant preclinical evidence and clinical trials of NK cell-based therapies.

Anti-Inflammatory and Anti-Oxidative Effects of AM404 in IL-1β-Stimulated SK-N-SH Neuroblastoma Cells.

An emerging number of studies address the involvement of neuroinflammation and oxidative stress in the pathophysiology of central nervous system (CNS) disorders such as depression, schizophrenia, anxiety, and neurodegenerative diseases. Different cytokines and molecules, such as prostaglandin (PG) E2, are associated with neuroinflammatory processes. The active acetaminophen metabolite AM404 has been shown to prevent inflammation and neuroinflammation in primary microglia and organotypic hippocampal slice cultures. However, its effects on pathophysiological conditions in the CNS and especially on neurons are still poorly understood. In this study, we therefore evaluated the effects of AM404 and acetaminophen on the arachidonic acid cascade and oxidative stress induced by interleukin (IL)-1β in human SK-N-SH neuronal cells. We observed that AM404 and acetaminophen significantly and concentration-dependent inhibited IL-1β-induced release of PGE2, independent of cyclooxygenases (COX)-1 and COX-2 enzymatic activity as well as COX-2 mRNA and protein levels in SK-N-SH-cells. The reduction of IL-1β-induced PGE2-release by AM404 and acetaminophen treatment might be mediated by the 8-iso-PGF2α pathway since IL-1β-induced synthesis of this free radical marker is dose-dependently reduced by both compounds, respectively. Therefore, understanding of the potential therapeutic properties of AM404 in neuroinflammation and oxidative stress might lead to future treatment options of different neurological disorders.

Cofilin Signaling in the CNS Physiology and Neurodegeneration.

All eukaryotic cells are composed of the cytoskeleton, which plays crucial roles in coordinating diverse cellular functions such as cell division, morphology, migration, macromolecular stabilization, and protein trafficking. The cytoskeleton consists of microtubules, intermediate filaments, and actin filaments. Cofilin, an actin-depolymerizing protein, is indispensable for regulating actin dynamics in the central nervous system (CNS) development and function. Cofilin activities are spatiotemporally orchestrated by numerous extra- and intra-cellular factors. Phosphorylation at Ser-3 by kinases attenuate cofilin’s actin-binding activity. In contrast, dephosphorylation at Ser-3 enhances cofilin-induced actin depolymerization. Cofilin functions are also modulated by various binding partners or reactive oxygen species. Although the mechanism of cofilin-mediated actin dynamics has been known for decades, recent research works are unveiling the profound impacts of cofilin dysregulation in neurodegenerative pathophysiology. For instance, oxidative stress-induced increase in cofilin dephosphorylation is linked to the accumulation of tau tangles and amyloid-beta plaques in Alzheimer’s disease. In Parkinson’s disease, cofilin activation by silencing its upstream kinases increases α-synuclein-fibril entry into the cell. This review describes the molecular mechanism of cofilin-mediated actin dynamics and provides an overview of cofilin’s importance in CNS physiology and pathophysiology.

Extracellular Mitochondria Signals in CNS Disorders.

Mitochondria actively participate in the regulation of cell respiratory mechanisms, metabolic processes, and energy homeostasis in the central nervous system (CNS). Because of the requirement of high energy, neuronal functionality and viability are largely dependent on mitochondrial functionality. In the context of CNS disorders, disruptions of metabolic homeostasis caused by mitochondrial dysfunction lead to neuronal cell death and neuroinflammation. Therefore, restoring mitochondrial function becomes a primary therapeutic target. Recently, accumulating evidence suggests that active mitochondria are secreted into the extracellular fluid and potentially act as non-cell-autonomous signals in CNS pathophysiology. In this mini-review, we overview findings that implicate the presence of cell-free extracellular mitochondria and the critical role of intercellular mitochondrial transfer in various rodent models of CNS disorders. We also discuss isolated mitochondrial allograft as a novel therapeutic intervention for CNS disorders.

Histone lysine methyltransferase SETDB1 as a novel target for central nervous system diseases.

Epigenetic changes that regulate chromatin structure have a major impact in genome stabilization and maintenance of cellular homeostasis, been recently implicated in the pathophysiology of central nervous system (CNS). Aberrant expression and dysregulation of histone modification enzymes has been associated with the development of several CNS disorders, revealing these enzymes as putative targets for drug development and novel therapeutic approaches. SETDB1 is a histone lysine methyltransferase responsible for the di- and tri-methylation of histone 3 (H3) at lysine (K) 9 in euchromatic regions further promoting gene silencing through heterochromatin formation. By this way, SETDB1 has been shown to regulate gene expression and influence normal cellular homeostasis required for nervous system function while it is also implicated in the pathogenesis of CNS disorders. Among them, brain tumors, schizophrenia, Huntington's disease, autism spectrum disorders along with alcohol-induced fetal neurobehavioral deficits and Prader-Willi syndrome are representative examples, indicating the aberrant expression and function of SETDB1 as a common pathogenic factor. In this review, we focus on SETDB1-associated molecular mechanisms implicated in CNS physiology and disease while we further discuss current pharmacological approaches targeting SETDB1 enzymatic activity with beneficial effects.

Microglia and Macrophages in the Pathological Central and Peripheral Nervous Systems.

Microglia, the immunocompetent cells in the central nervous system (CNS), have long been studied as pathologically deteriorating players in various CNS diseases. However, microglia exert ameliorating neuroprotective effects, which prompted us to reconsider their roles in CNS and peripheral nervous system (PNS) pathophysiology. Moreover, recent findings showed that microglia play critical roles even in the healthy CNS. The microglial functions that normally contribute to the maintenance of homeostasis in the CNS are modified by other cells, such as astrocytes and infiltrated myeloid cells; thus, the microglial actions on neurons are extremely complex. For a deeper understanding of the pathophysiology of various diseases, including those of the PNS, it is important to understand microglial functioning. In this review, we discuss both the favorable and unfavorable roles of microglia in neuronal survival in various CNS and PNS disorders. We also discuss the roles of blood-borne macrophages in the pathogenesis of CNS and PNS injuries because they cooperatively modify the pathological processes of resident microglia. Finally, metabolic changes in glycolysis and oxidative phosphorylation, with special reference to the pro-/anti-inflammatory activation of microglia, are intensively addressed, because they are profoundly correlated with the generation of reactive oxygen species and changes in pro-/anti-inflammatory phenotypes.

Characterization of Fluid Biomarkers Reveals Lysosome Dysfunction and Neurodegeneration in Neuronopathic MPS II Patients.

Mucopolysaccharidosis type II is a lysosomal storage disorder caused by a deficiency of iduronate-2-sulfatase (IDS) and characterized by the accumulation of the primary storage substrate, glycosaminoglycans (GAGs). Understanding central nervous system (CNS) pathophysiology in neuronopathic MPS II (nMPS II) has been hindered by the lack of CNS biomarkers. Characterization of fluid biomarkers has been largely focused on evaluating GAGs in cerebrospinal fluid (CSF) and the periphery; however, GAG levels alone do not accurately reflect the broad cellular dysfunction in the brains of MPS II patients. We utilized a preclinical mouse model of MPS II, treated with a brain penetrant form of IDS (ETV:IDS) to establish the relationship between markers of primary storage and downstream pathway biomarkers in the brain and CSF. We extended the characterization of pathway and neurodegeneration biomarkers to nMPS II patient samples. In addition to the accumulation of CSF GAGs, nMPS II patients show elevated levels of lysosomal lipids, neurofilament light chain, and other biomarkers of neuronal damage and degeneration. Furthermore, we find that these biomarkers of downstream pathology are tightly correlated with heparan sulfate. Exploration of the responsiveness of not only CSF GAGs but also pathway and disease-relevant biomarkers during drug development will be crucial for monitoring disease progression, and the development of effective therapies for nMPS II.

Characterisation of the cerebrospinal fluid of horses with West Nile virus neuroinvasive disease.

West Nile virus (WNV) is a zoonotic arbovirus transmitted by mosquitoes between wild birds (natural hosts) and other vertebrates. Horses and humans are incidental, dead-end hosts, but can develop severe neurological disorders. Owing to the close contact of cerebrospinal fluid (CSF) with the extracellular fluid of the brain, the analysis of CSF composition can reflect central nervous system (CNS) impairments enabling the diagnosis and understanding of various neurodegenerative CNS disorders. Our objective was to compare the findings from the CSF samples of horses with neuroinvasive WNV infection with those of healthy controls. We compared findings from fifteen CSF samples of 13 horses with acute WNV encephalomyelitis with those of 20 healthy controls. Protein, particular enzymes and ions, glucose and lactate showed abnormal levels in a significant number of WNV cases. None of the six horses with elevated glucose concentrations survived. Rather neutrophilic than mononuclear pleocytosis was identified with WNV infection. Neutrophils probably play a role in the development of inflammatory response and brain damage. Although elevated glucose levels reliably predicted the outcome, they might be the consequence of increased plasma levels and reflect general stress rather than CNS pathophysiology. The CSF findings of WNV encephalomyelitis patients are non-specific and variable but facilitate the differential diagnosis.