The rockefeller university

Background Microsatellite instability-high (MSI-H)/mismatch repair deficiency (dMMR) is a biomarker for responses to immune checkpoint inhibitors (ICIs). Whether mechanisms underlying microsatellite instability alter responses to ICIs is unclear. This article reports data from a prospective phase 2 pilot study of pembrolizumab in patients with recurrent MSI-H endometrial cancer (EC) analyzed by whole exome sequencing (WES) and potential mechanisms of primary/secondary ICI resistance (NCT02899793). Methods Patients with measurable MSI-H/dMMR EC confirmed by polymerase chain reaction/immunohistochemistry were evaluated by WES and received 200 mg of pembrolizumab every 3 weeks for <= 2 years. The primary end point was the objective response rate (ORR). Secondary end points included progression-free survival (PFS) and overall survival (OS). Results Twenty-five patients (24 evaluable) were treated. Six patients (25%) harbored Lynch/Lynch-like tumors, whereas 18 (75%) had sporadic EC. The tumor mutation burden was higher in Lynch-like tumors (median, 2939 mutations/megabase [Mut/Mb]; interquartile range [IQR], 867-5108 Mut/Mb) than sporadic tumors (median, 604 Mut/Mb; IQR, 411-798 Mut/Mb; P = .0076). The ORR was 100% in Lynch/Lynch-like patients but only 44% in sporadic patients (P = .024). The 3-year PFS and OS proportions were 100% versus 30% (P = .017) and 100% versus 43% (P = .043), respectively. Conclusions This study suggests prognostic significance of Lynch-like cancers versus sporadic MSI-H/dMMR ECs for ORR, PFS, and OS when patients are treated with pembrolizumab. Larger confirmatory studies in ECs and other MSI-H/dMMR tumors are necessary. Defective antigen processing/presentation and deranged induction in interferon responses serve as mechanisms of resistance in sporadic MSI-H ECs. Oligoprogression in MSI-H/dMMR patients appears salvageable with surgical resection and/or local treatment and the continuation of pembrolizumab off study. Clinical studies evaluating separate MSI-H/dMMR EC subtypes treated with ICIs are warranted.

Therapeutic human IgG antibodies are routinely tested in mouse models of oncologic, infectious, and autoimmune diseases. However, assessing the efficacy and safety of long-term administration of these agents has been limited by endogenous anti-human IgG immune responses that act to clear human IgG from serum and relevant tissues, thereby reducing their efficacy and contributing to immune complex-mediated pathologies, confounding evaluation of potential toxicity. For this reason, human antibody treatment in mice is generally limited in duration and dosing, thus failing to recapitulate the potential clinical applications of these therapeutics. Here, we report the development of a mouse model that is tolerant of chronic human antibody administration. This model combines both a human IgG1 heavy chain knock-in and a full recapitulation of human Fc receptor (Fc gamma R) expression, providing a unique platform for in vivo testing of human monoclonal antibodies with relevant receptors beyond the short term. Compared to controls, hIgG1 knock-in mice mount minimal anti-human IgG responses, allowing for the persistence of therapeutically active circulating human IgG even in the late stages of treatment in chronic models of immune thrombocytopenic purpura and metastatic melanoma.

Decrypting the B cell ontogeny of HIV-1 broadly neutralizing antibodies (bNAbs) is paramount for vaccine design. Here, we characterized IgA and IgG bNAbs of three distinct B cell lineages in a viremic controller, two of which comprised only IgG(+) or IgA(+) blood memory B cells; the third combined both IgG and IgA clonal variants. 7-269 bNAb in the IgA-only lineage displayed the highest neutralizing capacity despite limited somatic mutation, and delayed viral rebound in humanized mice. bNAbs in all three lineages targeted the N332 glycan supersite. The 2.8-angstrom resolution cryo-EM structure of 7-269-BG505 SOSIP.664 complex showed a similar pose as 2G12, on an epitope mainly composed of sugar residues comprising the N332 and N295 glycans. Binding and cryo-EM structural analyses showed that antibodies from the two other lineages interact mostly with glycans N332 and N386. Hence, multiple B cell lineages of IgG and IgA bNAbs focused on a unique HIV-1 site of vulnerability can codevelop in HIV-1 viremic controllers.

During normal vision, our eyes provide the brain with a continuous stream of useful information about the world. How visually specialized areas of the cortex, such as face-selective patches, operate under natural modes of behavior is poorly understood. Here we report that, during the free viewing of movies, cohorts of face-selective neurons in the macaque cortex fractionate into distributed and parallel subnetworks that carry distinct information. We classified neurons into functional groups on the basis of their movie-driven coupling with functional magnetic resonance imaging time courses across the brain. Neurons from each group were distributed across multiple face patches but intermixed locally with other groups at each recording site. These findings challenge prevailing views about functional segregation in the cortex and underscore the importance of naturalistic paradigms for cognitive neuroscience.

In their complex, the SARS-CoV-2 nsp13 helicase and RNA polymerase would translocate on RNA in opposite directions. Cryo-EM and MD simulations resolve this conundrum, suggesting an allosteric mechanism to turn the helicase on and off. The SARS-CoV-2 nonstructural proteins coordinate genome replication and gene expression. Structural analyses revealed the basis for coupling of the essential nsp13 helicase with the RNA-dependent RNA polymerase (RdRp) where the holo-RdRp and RNA substrate (the replication-transcription complex or RTC) associated with two copies of nsp13 (nsp13(2)-RTC). One copy of nsp13 interacts with the template-RNA in an opposing polarity to the RdRp and is envisaged to drive the RdRp backward on the RNA template (backtracking), prompting questions as to how the RdRp can efficiently synthesize RNA in the presence of nsp13. Here we use cryogenic-electron microscopy and molecular dynamics simulations to analyze the nsp13(2)-RTC, revealing four distinct conformational states of the helicases. The results indicate a mechanism for the nsp13(2)-RTC to turn backtracking on and off, using an allosteric mechanism to switch between RNA synthesis or backtracking in response to stimuli at the RdRp active site.

Background: Frontal fibrosing alopecia (FFA) is a progressive, scarring alopecia of the frontotemporal scalp that poses a substantial burden on quality of life. Large-scale global profiling of FFA is lacking, preventing the development of effective therapeutics. Objective: To characterize FFA compared to normal and alopecia areata using broad molecular profiling and to identify biomarkers linked to disease severity. Methods: This cross-sectional study assessed 33,118 genes in scalp using RNA sequencing and 350 proteins in serum using OLINK high-throughput proteomics. Disease biomarkers were also correlated with clinical severity and a fibrosis gene set. Results: Genes differentially expressed in lesional FFA included markers related to Th1 (IFN gamma/CXCL9/CXCL10), T-cell activation (CD2/CD3/CCL19/ICOS), fibrosis (CXCR3/FGF14/FGF22/VIM/FN1), T-regulatory (FOXP3/TGFB1/TGFB3), and Janus kinase/JAK (JAK3/STAT1/STAT4) (Fold changes [FCH]>1.5, FDR<.05 for all). Only one protein, ADM, was differentially expressed in FFA serum compared to normal (FCH>1.3, FDR>.05). Significant correlations were found between scalp biomarkers (IL-36RN/IL-25) and FFA severity, as well as between JAK/STAT and fibrosis gene-sets (r>6; P<.05). Limitations: This study was limited by a small sample size and predominantly female FFA patients. Conclusion: Our data characterize FFA as an inflammatory condition limited to scalp, involving Th1/JAK skewing, with associated fibrosis and elevated T-regulatory markers, suggesting the potential for disease reversibility with JAK/STAT inhibition.

Mechano-responsive signaling pathways enable blood vessels within a connected network to structurally adapt to partition of blood flow between organ systems. Wall shear stress (WSS) modulates endothelial cell proliferation and arteriovenous specification. Here, we study vascular regeneration in a zebrafish model by using tail amputation to disrupt the embryonic circulatory loop (ECL) at 3 days post fertilization (dpf). We observed a local increase in blood flow and peak WSS in the Segmental Artery (SeA) immediately adjacent to the amputation site. By manipulating blood flow and WSS via changes in blood viscosity and myocardial contractility, we show that the angiogenic Notch-ephrinb2 cascade is hemodynamically activated in the SeA to guide arteriogenesis and network reconnection. Taken together, ECL amputation induces changes in microvascular topology to partition blood flow and increase WSS-mediated Notch-ephrinb2 pathway, promoting new vascular arterial loop formation and restoring microcirculation.

Glutamate receptors have a key role in the neurobiology of opioid addiction. Using electron microscopic immunocytochemical methods, this project elucidates how sex and chronic immobilization stress (CIS) impact the redistribution of GluN1 and GluA1 within rat hippocampal CA3 pyramidal cells following oxycodone (Oxy) conditioned place preference (CPP). Four groups of female and male Sprague-Dawley rats subjected to CPP were used: Saline- (Sal) and Oxy-injected (3 mg/kg, I.P.) naive rats; and Sal- and Oxy-injected CIS rats. GluN1: In both naive and CIS rats, Sal-females compared to Sal-males had elevated cytoplasmic and total dendritic GluN1. Following Oxy CPP, near plasmalemmal, cytoplasmic, and total GluN1 decreased in CA3 dendrites of unstressed females suggesting reduced pools of GluN1 available for ligand binding. Following CIS, Oxy-males (which did not acquire CPP) had increased GluN1 in all compartments of dendrites and spines of CA3 neurons. GluA1: There were no differences in the distribution GluA1 in any cellular compartments of CA3 dendrites in naive females and males following either Sal or Oxy CPP. CIS alone increased the percent of GluA1 in CA3 dendritic spines in males compared to females. CIS Oxy-males compared to CIS Sal-males had an increase in cytoplasmic and total dendritic GluA1. Thus, in CIS Oxy-males increased pools of GluN1 and GluA1 are available for ligand binding in CA3 neurons. Together with our prior experiments, these changes in GluN1 and GluA1 following CIS in males may contribute to an increased sensitivity of CA3 neurons to glutamate excitation and a reduced capacity to acquire Oxy CPP.

SARS-CoV-2 infection is benign in most individuals but, in around 10% of cases, it triggers hypoxaemic COVID-19 pneumonia, which leads to critical illness in around 3% of cases. The ensuing risk of death (approximately 1% across age and gender) doubles every five years from childhood onwards and is around 1.5 times greater in men than in women. Here we review the molecular and cellular determinants of critical COVID-19 pneumonia. Inborn errors of type I interferons (IFNs), including autosomal TLR3 and X-chromosome-linked TLR7 deficiencies, are found in around 1-5% of patients with critical pneumonia under 60 years old, and a lower proportion in older patients. Pre-existing auto-antibodies neutralizing IFN alpha, IFN beta and/or IFN omega, which are more common in men than in women, are found in approximately 15-20% of patients with critical pneumonia over 70 years old, and a lower proportion in younger patients. Thus, at least 15% of cases of critical COVID-19 pneumonia can be explained. The TLR3- and TLR7-dependent production of type I IFNs by respiratory epithelial cells and plasmacytoid dendritic cells, respectively, is essential for host defence against SARS-CoV-2. In ways that can depend on age and sex, insufficient type I IFN immunity in the respiratory tract during the first few days of infection may account for the spread of the virus, leading to pulmonary and systemic inflammation.