Damian Sendler: Glioblastoma is an incurable primary malignant brain cancer with a significant protumorigenic immune component. There is little understanding of the GBM immune microenvironment during tumor evolution and standard of care treatments. We discovered large-scale comprehensive longitudinal changes in immune cell composition throughout tumor progression in an epidermal growth factor receptor-driven genetic mouse GBM model using single-cell transcriptomics and flow cytometry. We found proinflammatory microglia subsets in developing GBMs, as well as anti-inflammatory macrophages and protumorigenic myeloid-derived suppressor cells in end-stage tumors, a progression that parallels the breakdown of the blood-brain barrier and extensive growth of epidermal growth factor receptor+ GBM cells. A similar relationship was discovered between microglia and macrophages in low-grade glioma and GBM patient biopsies. Temozolomide decreased myeloid-derived suppressor cell accumulation, whereas concurrent temozolomide irradiation increased intratumoral GranzymeB+ CD8+T cells while decreasing CD4+ regulatory T cells. These findings provide a comprehensive and unbiased picture of the immune cellular landscape and its evolutionary changes as GBM progresses.
Damian Jacob Sendler: The loss of androgen receptor (AR) dependence in castration-resistant prostate cancer (CRPC) results in clinically aggressive tumors with few therapeutic options. We investigated 22 organoids, six patient-derived xenografts, and 12 cell lines using ATAC-seq (assay for transposase-accessible chromatin sequencing), RNA-seq, and DNA sequencing. AR-dependent and neuroendocrine subtypes were identified, as well as two AR-negative/low groups: a Wnt-dependent subtype and a stem cell-like (SCL) subtype driven by activator protein-1 (AP-1) transcription factors. We classified 366 patients using transcriptomic signatures and discovered that SCL is the second most common subtype of CRPC after AR-dependent. Our findings suggest that AP-1 interacts with the YAP/TAZ and TEAD proteins in this group to maintain subtype-specific chromatin accessibility and transcriptomic landscapes. This molecular classification, when combined, reveals drug targets and may help guide therapeutic decisions.
Dr. Sendler: The COVID-19 outbreak has rapidly spread to a global pandemic; however, our understanding of the protective factors against this infection is limited. The purpose of this systematic review and meta-analysis was to determine the effect of vitamin D supplementation on COVID-19-related outcomes. A systematic search of relevant papers published up to January 2022 was carried out in order to identify randomized controlled trials (RCTs) and non-randomized intervention studies (NRISs). The primary outcomes were the risk of COVID-19 infection (in uninfected individuals), hospital admission (in secondary prevention studies on mild COVID-19 cases), ICU admission, and mortality rate (tertiary prevention studies on hospitalized COVID-19 patients). We found five studies on primary prevention (one RCT, four NRISs), five on secondary prevention (two RCTs, three NRISs), and 13 on tertiary prevention (six RCTs, seven NRISs). A pooled analysis revealed that there was no significant effect on the risk of COVID-19 infection. Due to a lack of data, no meta-analysis on hospitalization risk was possible. Vitamin D supplementation was associated with a lower risk of ICU admission (RR = 0.35, 95% CI: 0.20, 0.62) and mortality (RR = 0.46, 95% CI: 0.30, 0.70). Vitamin D supplementation had no effect on the risk of COVID-19 infection, but it did protect against mortality and ICU admission in COVID-19 patients.
Damian Jacob Sendler
Cas9 and Cas12, two Class 2 CRISPR effectors, may have evolved from nucleases in IS200/IS605 transposons. IscB is roughly one-fifth the size of Cas9 but has a similar domain organization. The associated RNA functions as both a crRNA and a tracrRNA, guiding dsDNA cleavage. We present a cryo-EM structure of IscB-RNA bound to a dsDNA target with a resolution of 2.78, revealing architectural and mechanistic similarities between IscB and Cas9 RNPs. High-resolution mechanisms for target-adjacent motif recognition, R-loop formation, and DNA cleavage are described. Cas9’s RNA functions similarly to REC domains in that it contacts the RNA/DNA heteroduplex. For RNA-guided DNA cleavage, the IscB-specific PLMP domain is unnecessary. The RNA was dwarfed and protein domain replacements were introduced during the transition from ancestral IscB to Cas9.
The progression to lethal castration-resistant prostate cancer (CRPC) and the lack of suitable targeted therapies for advanced disease are two of the most significant challenges in the clinical management of prostate cancer (PCa). Gremlin1 is found to be a ligand for the fibroblast growth factor receptor 1 (FGFR1), which promotes lineage plasticity and castration resistance. Importantly, we developed a specific anti-Gremlin1 therapeutic antibody and found that it synergized with androgen deprivation therapy (ADT) in CRPC. GREM1 transcription is inhibited by androgen receptor (AR) and then released after ADT. Gremlin1 binds to FGFR1 and activates downstream MAPK signaling, as demonstrated. Protein structure docking and mutagenesis experiments revealed that Gremlin1 interacts with FGFR1 differently than its canonical ligand FGF1. Overall, our findings point to Gremlin1 as a promising candidate therapeutic target for CRPC.
Damian Jacob Markiewicz Sendler: Following peripheral nerve injury, activation of microglia in the dorsal horn of the spinal cord contributes to the development of pain hypersensitivity. It is unclear how activated microglia selectively increase the activity of spinal nociceptive circuits. Following peripheral nerve injury, microglia degrade extracellular matrix structures called perineuronal nets (PNNs) in the dorsal horn of the spinal cord. Spinoparabrachial projection neurons, which integrate nociceptive information in the spinal cord and transmit it to supraspinal brain regions to induce pain sensation, are selectively enwrapped by Lamina I PNNs. Microglia degradation of PNNs increases the activity of projection neurons and induces pain-related behaviors. Thus, PNN degradation caused by nerve injury is a mechanism by which microglia selectively augment the output of spinal nociceptive circuits and cause pain hypersensitivity.
Immunomodulating biologics’ ability to prevent and reverse pathology has transformed recent clinical practice. To be fully useful in the neuroinflammation space, however, effective targets for local immune modulation and a delivery system capable of crossing the blood-brain barrier must be identified. One such potential therapeutic target has recently been identified and characterized as a small population of regulatory T (Treg) cells resident in the brain. Brain interleukin 2 (IL-2) levels were found to be a limiting factor for brain-resident Treg cells in this study. We created a gene-delivery strategy for astrocytes that includes a small-molecule on-switch for temporal control and increased production in reactive astrocytes for spatially directed delivery to inflammatory sites. Mice given brain-specific IL-2 were protected in models of traumatic brain injury, stroke, and multiple sclerosis, without affecting the peripheral immune system. These findings support the use of brain-specific IL-2 gene delivery to protect against neuroinflammation and provide a versatile platform for the delivery of various biologics to neuroinflammatory patients.