Catálogo de publicaciones - revistas

<jats:title>Developing neurons practice for real life</jats:title> <jats:p> As a mouse runs forward across the forest floor, the scenery that it passes flows backwards. Ge <jats:italic>et al</jats:italic> . show that the developing mouse retina practices in advance for what the eyes must later process as the mouse moves. Spontaneous waves of retinal activity flow in the same pattern as would be produced days later by actual movement through the environment. This patterned, spontaneous activity refines the responsiveness of cells in the brain’s superior colliculus, which receives neural signals from the retina to process directional information. —PJH </jats:p>

<jats:title>Intestinal HDL is hepatoprotective</jats:title> <jats:p> High-density lipoprotein (HDL) is important for cholesterol metabolism and may have anti-inflammatory and antimicrobial properties. Although HDL is mainly produced by the liver, the intestine is also a source. Han <jats:italic>et al.</jats:italic> show in mice that intestinal HDL is not routed to the systemic circulation. Rather, in the form of HDL3, it is directly transported to the liver through the hepatic portal vein. There, it sequesters bacterial lipopolysaccharide from the gut that can trigger inflammation and liver damage. In various models of liver injury, loss of enteric HDL exacerbated pathology. By contrast, drugs elevating intestinal HDL improved disease outcomes. HDL3 is enriched in human portal venous blood, suggesting that enteric HDL may be targetable for the treatment of liver disease. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abe6729, this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abe6729">eabe6729</jats:related-article> </jats:p>

<jats:title>Getting around the blood–brain barrier</jats:title> <jats:p> The meninges comprise three membranes that surround and protect the central nervous system (CNS). Recent studies have noted the existence of myeloid cells resident there, but little is known about their ontogeny and function, and whether other meningeal immune cell populations have important roles remains unclear (see the Perspective by Nguyen and Kubes). Cugurra <jats:italic>et al.</jats:italic> found in mice that a large proportion of continuously replenished myeloid cells in the dura mater are not blood derived, but rather transit from cranial bone marrow through specialized channels. In models of CNS injury and neuroinflammation, the authors demonstrated that these myeloid cells have an immunoregulatory phenotype compared with their more inflammatory blood-derived counterparts. Similarly, Brioschi <jats:italic>et al.</jats:italic> show that the meninges host B cells that are also derived from skull bone marrow, mature locally, and likely acquire a tolerogenic phenotype. They further found that the brains of aging mice are infiltrated by a second population of age-associated B cells, which come from the periphery and may differentiate into autoantibody-secreting plasma cells after encountering CNS antigens. Together, these two studies may inform future treatment of neurological diseases. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abf7844, abf9277, this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abf7844">eabf7844</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abf9277">eabf9277</jats:related-article> ; see also abj8183, p. <jats:related-article issue="6553" page="396" related-article-type="in-this-issue" vol="373">396</jats:related-article> </jats:p>

<jats:title>Getting around the blood–brain barrier</jats:title> <jats:p> The meninges comprise three membranes that surround and protect the central nervous system (CNS). Recent studies have noted the existence of myeloid cells resident there, but little is known about their ontogeny and function, and whether other meningeal immune cell populations have important roles remains unclear (see the Perspective by Nguyen and Kubes). Cugurra <jats:italic>et al.</jats:italic> found in mice that a large proportion of continuously replenished myeloid cells in the dura mater are not blood derived, but rather transit from cranial bone marrow through specialized channels. In models of CNS injury and neuroinflammation, the authors demonstrated that these myeloid cells have an immunoregulatory phenotype compared with their more inflammatory blood-derived counterparts. Similarly, Brioschi <jats:italic>et al.</jats:italic> show that the meninges host B cells that are also derived from skull bone marrow, mature locally, and likely acquire a tolerogenic phenotype. They further found that the brains of aging mice are infiltrated by a second population of age-associated B cells, which come from the periphery and may differentiate into autoantibody-secreting plasma cells after encountering CNS antigens. Together, these two studies may inform future treatment of neurological diseases. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abf7844, abf9277, this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abf7844">eabf7844</jats:related-article> , p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abf9277">eabf9277</jats:related-article> ; see also abj8183, p. <jats:related-article issue="6553" page="396" related-article-type="in-this-issue" vol="373">396</jats:related-article> </jats:p>

<jats:title>Go big or you'll get lost</jats:title> <jats:p> Rational mutagenesis is a common approach to investigating or engineering enzyme function in vitro, but the ease with which one can manipulate protein sequences belies many pitfalls in connecting sparse activity data to an enzyme's true functional landscape. Using a high-throughput platform, Markin <jats:italic>et al.</jats:italic> expressed, purified, and performed an array of kinetic measurements on a target esterase, collecting data from &gt;1000 mutations spanning the entire protein (see the Perspective by Baumer and Whitehead). Protein misfolding into an inactive state, rather than decreased equilibrium stability, was a crucial factor in negatively affected variants spread throughout the protein. When combined with prior mechanistic understanding and structures, four “functional components” help to rationalize the otherwise complex spatial pattern of effects of mutations on different aspects of enzyme function, all of which would be invisible from mutagenesis of just a few residues. </jats:p> <jats:p> <jats:italic>Science</jats:italic> , abf8761, this issue p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" related-article-type="in-this-issue" xlink:href="10.1126/science.abf8761">eabf8761</jats:related-article> ; see also abj8346, p. <jats:related-article issue="6553" page="391" related-article-type="in-this-issue" vol="373">391</jats:related-article> </jats:p>

<jats:p>Finally, in the United States, colleges and universities are ramping up for a relatively normal school year. Most pandemic restrictions have been lifted and—barring any unforeseen new coronavirus variants—parents and students will soon be pulling up to residence halls and unloading their belongings. At many schools in “blue” states, there will be a great deal of confidence that good times are on the horizon as everyone there will have shown proof of vaccination against COVID-19. But for some public universities in “red” states, where vaccine mandates are not permitted, an aura of uncertainty will hang over the campus and the local community, a foreboding sense that another outbreak could be at hand.</jats:p>

<jats:p>A roundup of weekly science policy and related news.</jats:p>

<jats:p>Despite improvements, flood forecasts sometimes failed to flag risks along smaller streams.</jats:p>

<jats:p>Physicians hope technology will help screen patients eligible for Biogen's controversial antibody, aducanumab.</jats:p>

<jats:p>The pandemic has transformed fieldwork and upended careers.</jats:p>