A novel long intergenic non-coding RNA, Nostrill, regulates iNOS gene transcription and neurotoxicity in microglia.

BACKGROUND: Microglia are resident immunocompetent and phagocytic cells in the CNS. Pro-inflammatory microglia, stimulated by microbial signals such as bacterial lipopolysaccharide (LPS), viral RNAs, or inflammatory cytokines, are neurotoxic and associated with pathogenesis of several neurodegenerative diseases. Long non-coding RNAs (lncRNA) are emerging as important tissue-specific regulatory molecules directing cell differentiation and functional states and may help direct proinflammatory responses of microglia. Characterization of lncRNAs upregulated in proinflammatory microglia, such as NR_126553 or 2500002B13Rik, now termed Nostrill (iNOS Transcriptional Regulatory Intergenic LncRNA Locus) increases our understanding of molecular mechanisms in CNS innate immunity. METHODS: Microglial gene expression array analyses and qRT-PCR were used to identify a novel long intergenic non-coding RNA, Nostrill, upregulated in LPS-stimulated microglial cell lines, LPS-stimulated primary microglia, and LPS-injected mouse cortical tissue. Silencing and overexpression studies, RNA immunoprecipitation, chromatin immunoprecipitation, chromatin isolation by RNA purification assays, and qRT-PCR were used to study the function of this long non-coding RNA in microglia. In vitro assays were used to examine the effects of silencing the novel long non-coding RNA in LPS-stimulated microglia on neurotoxicity. RESULTS: We report here characterization of intergenic lncRNA, NR_126553, or 2500002B13Rik now termed Nostrill (iNOS Transcriptional Regulatory Intergenic LncRNA Locus). Nostrill is induced by LPS stimulation in BV2 cells, primary murine microglia, and in cortical tissue of LPS-injected mice. Induction of Nostrill is NF-κB dependent and silencing of Nostrill decreased inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production in BV2 and primary microglial cells. Overexpression of Nostrill increased iNOS expression and NO production. RNA immunoprecipitation assays demonstrated that Nostrill is physically associated with NF-κB subunit p65 following LPS stimulation. Silencing of Nostrill significantly reduced NF-κB p65 and RNA polymerase II recruitment to the iNOS promoter and decreased H3K4me3 activating histone modifications at iNOS gene loci. In vitro studies demonstrated that silencing of Nostrill in microglia reduced LPS-stimulated microglial neurotoxicity. CONCLUSIONS: Our data indicate a new regulatory role of the NF-κB-induced Nostrill and suggest that Nostrill acts as a co-activator of transcription of iNOS resulting in the production of nitric oxide by microglia through modulation of epigenetic chromatin remodeling. Nostrill may be a target for reducing the neurotoxicity associated with iNOS-mediated inflammatory processes in microglia during neurodegeneration.

Microglia induce neurogenic protein expression in primary cortical cells by stimulating PI3K/AKT intracellular signaling in vitro.

Emerging evidence suggests that microglia can support neurogenesis. Little is known about the mechanisms by which microglia regulate the cortical environment and stimulate cortical neurogenesis. We used an in vitro co-culture model system to investigate the hypothesis that microglia respond to soluble signals from cortical cells, particularly following mechanical injury, to alter the cortical environment and promote cortical cell proliferation, differentiation, and survival. Analyses of cortical cell proliferation, cell death, neurogenic protein expression, and intracellular signaling were performed on uninjured and injured cortical cells in co-culture with microglial cell lines. Microglia soluble cues enhanced cortical cell viability and proliferation cortical cells. Co-culture of injured cortical cells with microglia significantly reduced cell death of cortical cells. Microglial co-culture significantly increased Nestin + and α-internexin + cortical cells. Multiplex ELISA and RT-PCR showed decreased pro-inflammatory cytokine production by microglia co-cultured with injured cortical cells. Inhibition of AKT phosphorylation in cortical cells blocked microglial-enhanced cortical cell viability and expression of neurogenic markers in vitro. This in vitro model system allows for assessment of the effect of microglial-derived soluble signals on cortical cell viability, proliferation, and stages of differentiation during homeostasis or following mechanical injury. These data suggest that microglia cells can downregulate inflammatory cytokine production following activation by mechanical injury to enhance proliferation of new cells capable of neurogenesis via activation of AKT intracellular signaling. Increasing our understanding of the mechanisms that drive microglial-enhanced cortical neurogenesis during homeostasis and following injury in vitro will provide useful information for future primary cell and in vivo studies.

Adjuvant radiotherapy mitigates impact of perineural invasion on oncologic outcomes in early-stage oral cavity squamous cell carcinoma. A multi-institutional analysis of 557 patients.

OBJECTIVES: Understand the prognostic impact of perineural invasion (PNI) in early-stage oral cavity squamous cell carcinoma (OCSCC). Assess the influence of adjuvant radiotherapy on outcomes of patients with PNI-positive early-stage OCSCC. MATERIALS AND METHODS: Retrospective seven-institution cohort study including patients with pathologic T1-2 N0-1 OCSCC who underwent primary surgery with negative margins. Outcomes included disease-free survival (DFS) and locoregional control (LRC). Cox proportional hazards models were used to evaluate oncologic outcomes. Interaction terms were introduced to assess relationships between PNI and adjuvant radiotherapy. RESULTS: Among 557 patients (mean (SD) age 61.0 (13.9), 47.2% female, 66.6% pathologic T1, 93.5% pathologic N0), 93 had PNI-positive tumors, among which 87.1% underwent neck dissection and 39.6% received radiotherapy. On multivariable analysis, PNI was associated with lower DFS and LRC. Adjuvant radiotherapy was not associated with improved outcomes on multivariable analysis of the entire cohort. However, among patients with PNI-positive tumors, adjuvant radiotherapy significantly decreased hazard for DFS. CONCLUSION: Among patients with low-risk, early-stage OCSCC, PNI was associated with worse DFS and LRC. In patients with PNI-positive tumors, adjuvant radiotherapy lowered hazard for DFS on multivariable analysis. These data support using adjuvant radiotherapy for patients with early-stage OCSCC with PNI.

The Long Non-Coding RNA Nostrill Regulates Transcription of Irf7 Through Interaction With NF-κB p65 to Enhance Intestinal Epithelial Defense Against Cryptosporidium parvum.

The cells of the intestinal epithelium establish the frontline for host defense against pathogens in the gastrointestinal tract and play a vital role in the initiation of the immune response. Increasing evidence supports the role of long non-coding RNAs (lncRNAs) as critical regulators of diverse cellular processes, however, their role in antimicrobial host defense is incompletely understood. In this study, we provide evidence that the lncRNA Nostrill is upregulated in the intestinal epithelium following infection by Cryptosporidium parvum, a globally prevalent apicomplexan parasite that causes significant diarrheal disease and an important opportunistic pathogen in the immunocompromised and AIDS patients. Induction of Nostrill in infected intestinal epithelial cells was triggered by NF-κB signaling and was observed to enhance epithelial defense by decreasing parasitic infection burden. Nostrill participates in the transcriptional regulation of C. parvum-induced Irf7 expression through interactions with NF-κB p65, and induction of Nostrill promotes epigenetic histone modifications and occupancy of RNA polymerase II at the Irf7 promoter. Our data suggest that the induction of Nostrill promotes antiparasitic defense against C. parvum and enhances intestinal epithelial antimicrobial defense through contributions to transcriptional regulation of immune-related genes, such as Irf7.

Development and Validation of Machine Learning Models for Predicting Occult Nodal Metastasis in Early-Stage Oral Cavity Squamous Cell Carcinoma.

Importance: Given that early-stage oral cavity squamous cell carcinoma (OCSCC) has a high propensity for subclinical nodal metastasis, elective neck dissection has become standard practice for many patients with clinically negative nodes. Unfortunately, for most patients without regional metastasis, this risk-averse treatment paradigm results in unnecessary morbidity. Objectives: To develop and validate predictive models of occult nodal metastasis from clinicopathological variables that were available after surgical extirpation of the primary tumor and to compare predictive performance against depth of invasion (DOI), the currently accepted standard. Design, Setting, and Participants: This diagnostic modeling study collected clinicopathological variables retrospectively from 7 tertiary care academic medical centers across the US. Participants included adult patients with early-stage OCSCC without nodal involvement who underwent primary surgical extirpation with or without upfront elective neck dissection. These patients were initially evaluated between January 1, 2000, and December 31, 2019. Exposures: Largest tumor dimension, tumor thickness, DOI, margin status, lymphovascular invasion, perineural invasion, muscle invasion, submucosal invasion, dysplasia, histological grade, anatomical subsite, age, sex, smoking history, race and ethnicity, and body mass index (calculated as weight in kilograms divided by height in meters squared). Main Outcomes and Measures: Occult nodal metastasis identified either at the time of elective neck dissection or regional recurrence within 2 years of initial surgery. Results: Of the 634 included patients (mean [SD] age, 61.2 [13.6] years; 344 men [54.3%]), 114 (18.0%) had occult nodal metastasis. Patients with occult nodal metastasis had a higher frequency of lymphovascular invasion (26.3% vs 8.1%; P < .001), perineural invasion (40.4% vs 18.5%; P < .001), and margin involvement by invasive tumor (12.3% vs 6.3%; P = .046) compared with those without pathological lymph node metastasis. In addition, patients with vs those without occult nodal metastasis had a higher frequency of poorly differentiated primary tumor (20.2% vs 6.2%; P < .001) and greater DOI (7.0 vs 5.4 mm; P < .001). A predictive model that was built with XGBoost architecture outperformed the commonly used DOI threshold of 4 mm, achieving an area under the curve of 0.84 (95% CI, 0.80-0.88) vs 0.62 (95% CI, 0.57-0.67) with DOI. This model had a sensitivity of 91.7%, specificity of 72.6%, positive predictive value of 39.3%, and negative predictive value of 97.8%. Conclusions and Relevance: Results of this study showed that machine learning models that were developed from multi-institutional clinicopathological data have the potential to not only reduce the number of pathologically node-negative neck dissections but also accurately identify patients with early OCSCC who are at highest risk for nodal metastases.

Assessing Prognostic Value of Quantitative Neck Dissection Quality Measures in Patients With Clinically Node-Negative Oral Cavity Squamous Cell Carcinoma.

Importance: In clinically localized (T1-2) oral cavity squamous cell carcinoma (OCSCC), regional lymph node metastasis is associated with a poor prognosis. Given the high propensity of subclinical nodal disease in these patients, upfront elective neck dissections (END) for patients with clinically node-negative disease are common and associated with better outcomes. Unfortunately, even with this risk-adverse treatment paradigm, disease recurrence still occurs, and our understanding of the factors that modulate this risk and alter survival have yet to be fully elucidated. Objective: To investigate the prognostic value of lymph node yield (LNY), lymph node ratio (LNR), and weighted LNR (wLNR) in patients with clinically node-negative T1-2 OCSCC. Design, Setting, and Participants: In this cohort study, data were collected retrospectively from 7 tertiary care academic medical centers. Overall, 523 patients with cT1-2N0 OCSCC who underwent elective neck dissections after primary surgical extirpation were identified. Exposures: Lymph node yield was defined as the number of lymph nodes recovered from elective neck dissection. Lymph node ratio was defined as the ratio of positive nodes against total LNY. Weighted LNR incorporated information from both LNY and LNR into a single continuous metric. Main Outcomes and Measures: Locoregional control (LRC) and disease-free survival (DFS) were both evaluated using nonparametric Kaplan-Meier estimators and semiparametric Cox regression. Results: On multivariable analysis, LNY less than or equal to 18 lymph nodes was found to be significantly associated with decreased LRC (aHR, 1.53; 95% CI, 1.04-2.24) and DFS (aHR, 1.46; 95% CI, 1.12-1.92) in patients with pN0 disease, but not those with pN-positive disease. Importantly, patients with pN0 disease with LNY less than or equal to 18 and those with pN1 diseasehad nearly identical 5-year LRC (69.7% vs 71.4%) and DFS (58.2% vs 55.7%). For patients with pN-positive disease, LNR greater than 0.06 was significantly associated with decreased LRC (aHR, 2.66; 95% CI, 1.28-5.55) and DFS (aHR, 1.65; 95% CI, 1.07-2.53). Overall, wLNR was a robust prognostic variable across all patients with cN0 disease, regardless of pathologic nodal status. Risk stratification via wLNR thresholds demonstrated greater optimism-corrected concordance compared with American Joint Committee on Cancer (AJCC) 8th edition nodal staging for both LRC (0.61 vs 0.57) and DFS (0.61 vs 0.58). Conclusions and Relevance: Movement toward more robust metrics that incorporate quantitative measures of neck dissection quality and regional disease burden, such as wLNR, could greatly augment prognostication in cT1-2N0 OCSCC by providing more reliable and accurate risk estimations.