La población de Sudamérica: nuevos aportes basados en el análisis de cráneos arcaicos y frecuencias génicas de aborígenes contemporáneos

El origen de los primeros habitantes de América ha inquietado a numerosos investigadores, quienes en el transcurso del último siglo han presentado un acopio de modelos de poblamiento más o menos controvertidos. En la actualidad, los especialistas concuerdan en que los primeros pobladores del Nuevo Mundo, corresponderían a primitivos grupos de cazadores y recolectores que habrían llegado a América desde el noreste de Asia utilizando un corredor terrestre actualmente cubierto por las aguas (el Estrecho de Bering), siguiendo probablemente el rastro de enormes animales pleistocénicos (Bryan 1978, Irwing 1985, Lynch 1983)Sociedad Argentina de Antropologí

La población de Sudamérica: nuevos aportes basados en el análisis de cráneos arcaicos y frecuencias génicas de aborígenes contemporáneos

El origen de los primeros habitantes de América ha inquietado a numerosos investigadores, quienes en el transcurso del último siglo han presentado un acopio de modelos de poblamiento más o menos controvertidos. En la actualidad, los especialistas concuerdan en que los primeros pobladores del Nuevo Mundo, corresponderían a primitivos grupos de cazadores y recolectores que habrían llegado a América desde el noreste de Asia utilizando un corredor terrestre actualmente cubierto por las aguas (el Estrecho de Bering), siguiendo probablemente el rastro de enormes animales pleistocénicos (Bryan 1978, Irwing 1985, Lynch 1983)Sociedad Argentina de Antropologí

Gut–Brain Interactions and Their Impact on Astrocytes in the Context of Multiple Sclerosis and Beyond

Multiple Sclerosis (MS) is a chronic autoimmune inflammatory disease of the central nervous system (CNS) that leads to physical and cognitive impairment in young adults. The increasing prevalence of MS underscores the critical need for innovative therapeutic approaches. Recent advances in neuroimmunology have highlighted the significant role of the gut microbiome in MS pathology, unveiling distinct alterations in patients’ gut microbiota. Dysbiosis not only impacts gut-intrinsic processes but also influences the production of bacterial metabolites and hormones, which can regulate processes in remote tissues, such as the CNS. Central to this paradigm is the gut–brain axis, a bidirectional communication network linking the gastrointestinal tract to the brain and spinal cord. Via specific routes, bacterial metabolites and hormones can influence CNS-resident cells and processes both directly and indirectly. Exploiting this axis, novel therapeutic interventions, including pro- and prebiotic treatments, have emerged as promising avenues with the aim of mitigating the severity of MS. This review delves into the complex interplay between the gut microbiome and the brain in the context of MS, summarizing current knowledge on the key signals of cross-organ crosstalk, routes of communication, and potential therapeutic relevance of the gut microbiome. Moreover, this review places particular emphasis on elucidating the influence of these interactions on astrocyte functions within the CNS, offering insights into their role in MS pathophysiology and potential therapeutic interventions.European research CouncilGerman Research Foundatio

Regional astrocyte IFN signaling restricts pathogenesis during neurotropic viral infection

Type I IFNs promote cellular responses to viruses, and IFN receptor (IFNAR) signaling regulates the responses of endothelial cells of the blood-brain barrier (BBB) during neurotropic viral infection. However, the role of astrocytes in innate immune responses of the BBB during viral infection of the CNS remains to be fully elucidated. Here, we have demonstrated that type I IFNAR signaling in astrocytes regulates BBB permeability and protects the cerebellum from infection and immunopathology. Mice with astrocyte-specific loss of IFNAR signaling showed decreased survival after West Nile virus infection. Accelerated mortality was not due to expanded viral tropism or increased replication. Rather, viral entry increased specifically in the hindbrain of IFNAR-deficient mice, suggesting that IFNAR signaling critically regulates BBB permeability in this brain region. Pattern recognition receptors and IFN-stimulated genes had higher basal and IFN-induced expression in human and mouse cerebellar astrocytes than did cerebral cortical astrocytes, suggesting that IFNAR signaling has brain region–specific roles in CNS immune responses. Taken together, our data identify cerebellar astrocytes as key responders to viral infection and highlight the existence of distinct innate immune programs in astrocytes from evolutionarily disparate regions of the CNS

The role of midkine in health and disease

Midkine (MDK) is a neurotrophic growth factor highly expressed during embryogenesis with important functions related to growth, proliferation, survival, migration, angiogenesis, reproduction, and repair. Recent research has indicated that MDK functions as a key player in autoimmune disorders of the central nervous system (CNS), such as Multiple Sclerosis (MS) and is a promising therapeutic target for the treatment of brain tumors, acute injuries, and other CNS disorders. This review summarizes the modes of action and immunological functions of MDK both in the peripheral immune compartment and in the CNS, particularly in the context of traumatic brain injury, brain tumors, neuroinflammation, and neurodegeneration. Moreover, we discuss the role of MDK as a central mediator of neuro-immune crosstalk, focusing on the interactions between CNS-infiltrating and -resident cells such as astrocytes, microglia, and oligodendrocytes. Finally, we highlight the therapeutic potential of MDK and discuss potential therapeutic approaches for the treatment of neurological disorders