Citations

BACKGROUND: Vascular large conductance Ca 2+ -activated K + (BK) channel, composed of the α-subunit (BK-α) and the β1-subunit (BK-β1), is a key determinant of coronary vasorelaxation and its function is impaired in diabetic vessels. However, our knowledge of diabetic BK channel dysregulation is incomplete. The Sorbs2 (Sorbin homology [SoHo] and Src homology 3 [SH3] domains-containing protein 2), is ubiquitously expressed in arteries, but its role in vascular pathophysiology is unknown. METHODS: The role of Sorbs2 in regulating vascular BK channel activity was determined using patch-clamp recordings, molecular biological techniques, and in silico analysis. RESULTS: Sorbs2 is not only a cytoskeletal protein but also an RNA-binding protein that binds to BK channel proteins and BK-α mRNA, regulating BK channel expression and function in coronary smooth muscle cells. Molecular biological studies reveal that the SH3 domain of Sorbs2 is necessary for Sorbs2 interaction with BK-α subunits, while both the SH3 and SoHo domains of Sorbs2 interact with BK-β1 subunits. Deletion of the SH3 or SoHo domains abolishes the Sorbs2 effect on the BK-α/BK-β1 channel current density. Additionally, Sorbs2 is a target gene of the Nrf2 (nuclear factor erythroid-2-related factor 2), which binds to the promoter of Sorbs2 and regulates Sorbs2 expression in coronary smooth muscle cells. In vivo studies demonstrate that Sorbs2 knockout mice at 4 months of age display a significant decrease in BK channel expression and function, accompanied by impaired BK channel Ca 2+ -sensitivity and BK channel-mediated vasodilation in coronary arteries, without altering their body weights and blood glucose levels. Importantly, Sorbs2 expression is significantly downregulated in the coronary arteries of db/db type 2 diabetic mice. CONCLUSIONS: Sorbs2, a downstream target of Nrf2, plays an important role in regulating BK channel expression and function in vascular smooth muscle cells. Vascular Sorbs2 is downregulated in diabetes. Genetic knockout of Sorbs2 manifests coronary BK channelopathy and vasculopathy observed in diabetic mice, independent of obesity and glucotoxicity.

Abstract Heterozygous germline variants in DDX41 are identified in ~5% of patients with Myelodysplastic Syndrome (MDS) or Acute Myeloid Leukemia (AML). Recognition of the hereditary nature of such cancers and a better understanding of the factors that affect progression to malignancy has deep implications for health surveillance of patients and relatives that share a pathogenic DNA variant. DDX41 has a role in ribosome biogenesis and in opposing R-loop accumulation at promoters, but the mechanisms through which DDX41 loss drives cancer development are poorly understood. In a collaboration between Cambridge, UK and Mayo Clinic, USA we identified 85 patients with germline DDX41 variants [73/85 with germline pathogenic variants (GPV) and 12 with variants of uncertain significance (VUS)]. The majority were identified through targeted myeloid NGS upon presentation with AML (30/85) or MDS (44/85). Average age at diagnosis was 65 (35-93) with male predominance (57/85). The most common GPV was the NM_016222.4(DDX41):c.415_418dup; p.D140Gfs*2 (15/85). The majority (53.4% 39/73), also acquired a somatic variants in the other DDX41 allele (referred to as GPV+Som). The most common somatic variant (82% 32/39) was the R525H, a variant predicted to reduce the ATPase function of the helicase domain. We hypothesise that the markedly reduced DDX41 activity in cells with biallelic variants, is a key cause of progression to overt malignancy. In our cohort, we observed that somatic variants occurred at a similar frequency in association with start loss, truncating, splice, in-frame deletion, and missense GPV. However, whereas MDS was the predominant diagnosis within GPV (67.6% 23/34, AML 26.4% 9/34), AML was the most frequent diagnosis within GPV+Som (AML 51%.2 20/39, MDS 38.4% 15/39). Overall, there was a significantly higher likelihood of AML in the presence of a somatic variant (p<0.05), suggesting that there might be a dosage effect on the phenotype. This pattern was observed across all the GPV, with the exception of missense, suggesting that many might be benign polymorphysms. In addition, although somatic variants are typically subclonal (overall mean variant allele fraction VAF=9.87%, 3-27.8%), we observed a higher somatic VAF in AML over MDS cases (12.4% vs 7.7% respectively p<0.05). A lower bone marrow cellularity was also characteristic of GPV+Som vs GPV alone (mean observed/expected cellularity for age 0.9 vs 1.32 respectively p<0.05). In two cases, serial bone marrow morphology and NGS data were available, and we observed marked reduction in bone marrow cellularity upon acquisition of the R525H clone. The mechanisms of AML evolution appear different in DDX41 HMMS compared to sporadic cases. Interestingly, over half of our patients (21/34 GPV and 23/39 GPV+Som) did not exhibit additional somatic drivers. Our work suggests that acquisition of a somatic variant is a critical event in disease progression. Furthermore, the near universally subclonal nature of somatic variants suggest that they may affect disease phenotype through non-cell autonomous mechanisms. Citation Format: Ludovica Marando, Talha Badar, Yael Kusne, Audrey Morris, Terra Lasho, Abhishek Mangaonkar, Christy Finke, Carles Crawley, James M. Foran, Aref Al-Kali, Andrew King, Hassan Alkhateeb, Naseema Gangat, Chi Wong, Rong He, David Viswanatha, Faisal Basheer, Mark Litzow, Alejandro Ferrer, George Vassiliou, Mrinal Patnaik. Investigating the role of the somatic DDX41 variant in the context of DDX41 hereditary myeloid malignancy syndromes (HMMS) [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr A037.

Introduction: Acute ischemic stroke (AIS) is thesecond leading cause of death globally, accounting for approximately 11% of alldeaths, long-term disability, and functional impairments in survivors. TheCOVID-19 pandemic has raised concerns about its impact on AIS patients. Aim: This study aimed to assess the outcomes,including mortality and severity of disability in AIS hospitalizations withCOVID-19. Methods: We performed a retrospective cross-sectionalanalysis of the Nationwide Inpatient Sample (NIS-2020) in adulthospitalizations for AIS to compare the outcomes [death & APRDRGseverity/disability] in COVID-19 patients using ICD-10 codes. We performedweighted analyses using chi-square, unpaired t-test, and multivariate logisticregression models to evaluate COVID-19-associated poor outcomes amongst AISpatients. Results: Out of 504,460 AIS patients, 7,590 had AIStriggered by COVID-19. Amongst AIS hospitalizations, COVID-19 was more frequentin age group >65 year old 63.2%, male 52.6%, White race (51.4%), patientwith Medicare (58.7%), median household income 0-25 percentile (33.6%), Southzone (43.4%), and hypertensives (83.7%). AIS patients with COVID-19 had ahigher mortality (10.93% vs 3.8%) and severe/extreme disability (93.21% vs37.43%) rates in comparison to patients without COVID-19. (p<0.0001) Inregression analysis COVID-19 was associated with 213% higher odds of mortality(aOR: 3.13, 95% CI: 2.90-3.38, p<0.0001, c:0.671) and higher odds of severe/extreme disability(26.85, 24.53-29.39, p<0.0001, c:0.686) compared to AIS patients withoutCOVID-19. Conclusion: These findings emphasize the substantialimpact of COVID-19 on AIS patients by elevating mortality and risk of severedisability compared to their counterparts. Efforts should be directed towards earlyidentification of stroke population that is at higher risk ofCOVID-19-associated poor outcome and prompt management tomitigate the burden of the both diseases.

Summary Stag Beetle Knife (SB Knife) is increasingly being utilized for Zenker’s Diverticulectomy (ZD). Our study assessed the effectiveness and safety of the SB Knife for the management of ZD. Ovid EBM reviews, Ovid Embase, Ovid Medline, ClinicalTrials.gov, Scopus, and Web of Science were searched to identify studies that utilized SB knife for ZD. Pooled proportions (PP) were calculated using the random-effects model. Heterogeneity was evaluated using I2 statistics. A total of 7 studies with 268 patients were included in the final analysis. Dysphagia and regurgitation were the most common clinical symptoms. The mean size of the ZD was 2.8 ± 0.7 cm and 28 (of 148) patients had undergone previous treatments. The PP of technical success was 98% (95% CI: 92.3–99.5; I20) with a mean procedure duration of 26.2 ± 8.3 minutes. The PP of clinical response at first follow-up and relapse after index procedure was 87.9% (95% CI: 81.6–92.3; I219) and 13.5% (95% CI: 9.6–18.6; I22), respectively. At final follow-up, the PP of clinical remission was 96.2% (95% CI: 91–98.4; I230.6) while the PP of procedure failure was 3.6% (95% CI: 1.6–8.1; I20). No severe adverse events (AEs) were noted while using the SB Knife. However, the PP of intraprocedural and postprocedural AEs was 13.2% (95% CI: 9.6–17.8; I20) and 9.3% (95% CI: 5.7–14.9; I2 &lt; 20.9), respectively. SB Knife is highly safe and effective for Zenker’s Diverticulectomy with a failure rate of only 3.6%.