The rockefeller university

Purpose of review The coronavirus disease 2019 (COVID-19) pandemic has caught the world unprepared, with no prevention or treatment strategies in place. In addition to the efforts to develop an effective vaccine, alternative approaches are essential to control this pandemic, which will most likely require multiple readily available solutions. Among them, monoclonal anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies have been isolated by multiple laboratories in record time facilitated by techniques that were first pioneered for HIV-1 antibody discovery. Here, we summarize how lessons learned from anti-HIV-1 antibody discovery have provided fundamental knowledge for the rapid development of anti-SARS-CoV-2 antibodies. Recent findings Research laboratories that successfully identified potent broadly neutralizing antibodies against HIV-1 have harnessed their antibody discovery techniques to isolate novel potent anti-SARS-CoV-2 antibodies, which have efficacy in animal models. These antibodies represent promising clinical candidates for treatment or prevention of COVID-19. Passive transfer of antibodies is a promising approach when the elicitation of protective immune responses is difficult, as in the case of HIV-1 infection. Antibodies can also play a significant role in post-exposure prophylaxis, in high-risk populations that may not mount robust immune responses after vaccination, and in therapy. We provide a review of the recent approaches used for anti-SARS-CoV-2 antibody discovery and upcoming challenges in the field.

Hidradenitis suppurativa (HS) is a chronic inflammatory dermatosis that imparts a significant burden on patients and presents a management challenge for healthcare providers. As attention to this debilitating condition has grown over recent years, our understanding of HS pathogenesis and optimal treatment approaches continues to evolve. Nine HS treatment guidelines developed by various expert organizations have been published, encompassing therapeutic modalities ranging from topical agents to systemic therapies to procedural interventions. These guidelines demonstrate significant overlap in treatment recommendations and have all been published within the last 5 years. Therefore, we aim to compare and synthesize the recommendations of international HS treatment guidelines and to encourage inter-organizational communication for the development of consensus or staggered publication of recommendations for HS management.

Mutations in histone H1 induce the remodelling of chromatin architecture to a more relaxed state, which leads to malignant transformation through changes in histone modifications and the expression of stem cell genes. Linker histone H1 proteins bind to nucleosomes and facilitate chromatin compaction(1), although their biological functions are poorly understood. Mutations in the genes that encode H1 isoforms B-E (H1B, H1C, H1D and H1E; also known as H1-5, H1-2, H1-3 and H1-4, respectively) are highly recurrent in B cell lymphomas, but the pathogenic relevance of these mutations to cancer and the mechanisms that are involved are unknown. Here we show that lymphoma-associated H1 alleles are genetic driver mutations in lymphomas. Disruption of H1 function results in a profound architectural remodelling of the genome, which is characterized by large-scale yet focal shifts of chromatin from a compacted to a relaxed state. This decompaction drives distinct changes in epigenetic states, primarily owing to a gain of histone H3 dimethylation at lysine 36 (H3K36me2) and/or loss of repressive H3 trimethylation at lysine 27 (H3K27me3). These changes unlock the expression of stem cell genes that are normally silenced during early development. In mice, loss of H1c and H1e (also known as H1f2 and H1f4, respectively) conferred germinal centre B cells with enhanced fitness and self-renewal properties, ultimately leading to aggressive lymphomas with an increased repopulating potential. Collectively, our data indicate that H1 proteins are normally required to sequester early developmental genes into architecturally inaccessible genomic compartments. We also establish H1 as a bona fide tumour suppressor and show that mutations in H1 drive malignant transformation primarily through three-dimensional genome reorganization, which leads to epigenetic reprogramming and derepression of developmentally silenced genes.

Pancreatic ductal adenocarcinoma (PDAC) cells require substantial metabolic rewiring to overcome nutrient limitations and immune surveillance. However, the metabolic pathways necessary for pancreatic tumor growth in vivo are poorly understood. To address this, we performed metabolism-focused CRISPR screens in PDAC cells grown in culture or engrafted in immunocompetent mice. While most metabolic gene essentialities are unexpectedly similar under these conditions, a small fraction of metabolic genes are differentially required for tumor progression. Among these, loss of heme synthesis reduces tumor growth due to a limiting role of heme in vivo, an effect independent of tissue origin or immune system. Our screens also identify autophagy as a metabolic requirement for pancreatic tumor immune evasion. Mechanistically, autophagy protects cancer cells from CD8+ T cell killing through TNF alpha-induced cell death in vitro. Altogether, this resource provides metabolic dependencies arising from microenvironmental limitations and the immune system, nominating potential anti-cancer targets.

Regeneration of skeletal muscle depends on resident muscle stem cells called satellite cells that in healthy, uninjured muscle remain quiescent (noncycling). After activation and expansion of satellite cells postinjury, satellite cell numbers return to uninjured levels and return to mitotic quiescence. Here, we show that the transcription factor CCAAT/enhancer-binding protein beta (C/EBP beta) is required to maintain quiescence of satellite cells in uninjured muscle. We show that C/EBP beta is expressed in quiescent satellite cells in vivo and upregulated in noncycling myoblasts in vitro. Loss of C/EBP beta in satellite cells promotes their premature exit from quiescence resulting in spontaneous activation and differentiation of the stem cell pool. Forced expression of C/EBP beta in myoblasts inhibits proliferation by upregulation of 28 quiescence-associated genes. Furthermore, we find that caveolin-1 is a direct transcriptional target of C/EBP beta and is required for cell cycle exit in muscle satellite cells expressing C/EBP beta. The induction of mitotic quiescence is considered necessary for the long-term maintenance of adult stem cell populations with dysregulation driving increased differentiation of progenitors and depletion of the stem cell pool. Our findings place C/EBP beta as an important transcriptional regulator of muscle satellite cell quiescence.

Within the hypothalamic paraventricular nucleus (PVN), estrogen receptor (ER) beta and other gonadal hormone receptors play a role in central cardiovascular processes. However, the influence of sex and age on the cellular and subcellular relationships of ER beta with ER alpha, G-protein ER (GPER1), as well as progestin and androgen receptors (PR and AR) in the PVN is uncertain. In young (2- to 3-month-old) females and males, ER beta-enhanced green fluorescent protein (EGFP) containing neurons were approximately four times greater than ER alpha-labeled and PR-labeled nuclei in the PVN. In subdivisions of the PVN, young females, compared to males, had: (1) more ER beta-EGFP neurons in neuroendocrine rostral regions; (2) fewer ER alpha-labeled nuclei in neuroendocrine and autonomic projecting medial subregions; and (3) more ER alpha-labeled nuclei in an autonomic projecting caudal region. In contrast, young males, compared to females, had approximately 20 times more AR-labeled nuclei, which often colocalized with ER beta-EGFP in neuroendocrine (approximately 70%) and autonomic (approximately 50%) projecting subregions. Ultrastructurally, in soma and dendrites, PVN ER beta-EGFP colocalized primarily with extranuclear AR (approximately 85% soma) and GPER1 (approximately 70% soma). Aged (12- to 24-month-old) males had more ER beta-EGFP neurons in a rostral neuroendocrine subregion compared to aged females and females with accelerated ovarian failure (AOF) and in a caudal autonomic subregion compared to post-AOF females. Late-aged (18- to 24-month-old) females compared to early-aged (12- to 14-month-old) females and AOF females had fewer AR-labeled nuclei in neuroendrocrine and autonomic projecting subregions. These findings indicate that gonadal steroids may directly and indirectly influence PVN neurons via nuclear and extranuclear gonadal hormone receptors in a sex-specific manner.

We established the COVID Human Genetic Effort (www.covidhge.com) to discover the human genetic and immunological bases of the vast interindividual clinical variability between humans infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We found that about 3% of patients with life-threatening coronavirus disease 2019 (COVID-19) pneumonia were ill because of inborn errors of genes controlling type I interferon (IFN)-dependent immunity (which controls influenza virus), and at least 10% of patients with life-threatening COVID-19 pneumonia had neutralizing auto-Abs against some of the 17 individual type I IFNs. These findings indicate that impaired type I IFN immunity underlies life-threatening COVID-19 pneumonia in at least 13% of patients. These discoveries pave the way for further research into unexplained severe cases, and provide a rationale for preventing and treating the disease in individuals at risk, with recombinant type I IFNs.

Eukaryotic transfer RNAs can become selectively fragmented upon various stresses, generating tRNA-derived small RNA fragments. Such fragmentation has been reported to impact a small fraction of the tRNA pool and thus presumed to not directly impact translation. We report that oxidative stress can rapidly generate tyrosine-tRNA(GUA) fragments in human cells-causing significant depletion of the precursor tRNA. Tyrosine-tRNA(GUA) depletion impaired translation of growth and metabolic genes enriched in cognate tyrosine codons. Depletion of tyrosine tRNA(GUA) or its translationally regulated targets USP3 and SCD repressed proliferation-revealing a dedicated tRNA-regulated growth-suppressive pathway for oxidative stress response. Tyrosine fragments are generated in a DIS3L2 exoribonuclease-dependent manner and inhibit hnRNPA1-mediated transcript destabilization. Moreover, tyrosine fragmentation is conserved in C. elegans. Thus, tRNA fragmentation can coordinately generate trans-acting small RNAs and functionally deplete a tRNA. Our findings reveal the existence of an underlying adaptive codon-based regulatory response inherent to the genetic code.