Citations

Renal artery stenosis (RAS) is a common public health problem, affecting up to 7% of individuals over 65 years of age. Optimal therapy for patients with RAS is controversial, as recent studies have indicated that revascularization via stenting fails to improve renal function or patient survival. Medical therapy is associated with high morbidity and mortality, primarily due to cardiovascular disease. However, morphologic correlates for reversibility following restoration of blood flow have not been adequately defined. The purpose of this study was to standardize an experimental model for the restoration of blood flow, employing a well characterized murine RAS model. Total N=10 C57B/6J male mice were used. RAS was induced on the right renal artery by putting a polytetrafluoroethylene cuff (N=6) and sham surgery was performed without cuff placement (N=4). To determine the feasibly of restoring the blood flow to the stenotic kidney, cuff was taken off at day 7 following the RAS surgery. Blood pressure measurements were done using tail cuff method at baseline, before taking cuff off and then every week until harvest. MRI images were captured using an Avance DRX 700WB spectrometer with a vertical 16.4 T wide bore magnet connected with the imaging tools at baseline, 3 days after putting the cuff on or sham surgery, and at 3 weeks after cuff off. The animals were harvested at day 28 following surgery and kidney weights are obtained. Baseline renal perfusion (1018±41.6 ml/100g/min) was significantly reduced (634.7±141.3 ml/100g/min, p=0.01) following cuff placement. Perfusion was restored to normal (955±59.8 ml/100g/min) at 28 days following cuff removal at 7 days after RAS. Similarly, volume of the stenotic kidney was significantly reduced (at day 3 after RAS 172±8.6 mm 3 ) compared to baseline (206.3±4.4 mm 3 , p=0.0007). There was no significant difference in perfusion and volume after cuff off compared to baseline and sham groups. There was no significant difference in kidney weight between cuff‐off (167± 4.7 mg) and sham groups (163±9.95 mg). Also, there was no difference in heart weight between cuff off (150±3.7mg) and sham groups (148±6.7mg). We conclude that this model will provide the basis for determining the latest time point associated with recovery of renal structure and potential histopathologic markers that predict preservation of renal structure following cuff removal. Also, this model would provide the basis for determining efficacy of additional therapies to target inflammation, etc. to widen the “therapeutic window” during which restoration of renal blood flow is beneficial. Support or Funding Information This project is funded by National Institutes of health, NIAID R01 AI100911.

CX3CR1 is a chemokine receptor widely expressed on inflammatory cells which recognizes CX3CL1 (fractalkine) a membrane bound chemokine that can function as an adhesion receptor. Blockade of CX3CR1 has been shown to reduce inflammation and chronic renal injury in a variety of models. We sought to determine whether CX3CR1 deficient mice are protected from chronic renal injury in experimental renal artery stenosis (RAS). RAS was established in CX3CR1 knockout (KO) and wild‐type C57BLK/6 mice (WT) through placement of a cuff on the right renal artery. Sham mice underwent manipulation of the right renal artery without placement of a cuff. As assessed by MRI, mean flow reduction was 65.3% in the WT mice and 66.5% in the KO mice (p=ns) subjected to RAS. Both KO and WT mice developed hypertension, which persisted throughout the 4 week study. KO and WT mice developed a similar degree of cardiac hypertrophy (166 mg WT, 172 mg KO, p=ns; 117 mg sham). Stenotic kidney weights were reduced to a similar extent in KO and WT mice (sham 148 mg, WT 83 mg, KO 53 mg) with compensatory hypertrophy of the contralateral kidney (sham 136 mg, WT 170 mg, KO 206 mg, p=0.0016 KO vs WT). The stenotic kidney of both KO and WT mice developed severe atrophy, characterized by flattening and simplification of tubular epithelium and influx of interstitial T cells and macrophages (32.8 % cortical surface area for WT and 76.4% cortical surface area for KO, p=0.01). The contralateral kidney was without significant histopathologic abnormality. We conclude that development of severe atrophy is not prevented in CX3CR1 KO mice, indicating that alternative pathways contribute to chronic renal damage in this model. Support or Funding Information This work is supported by NIH Grant R01 AI100911.

Abstract Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer with limited therapeutic strategy and unfavorable prognosis, especially for patients bearing brain metastasis. Here, we demonstrate that MTAP gene deletion or MTAP inhibition by MTAP inhibitor, MTDIA, sensitizes breast cancer cells to poly (ADP-ribose) polymerase (PARP) inhibitor (PARPi). Mechanistically, PARPi suppresses the expression of methionine adenosyltransferase 2A (MAT2A) by inducing METTL16 auto-inhibition mediated intron retention. Given that MAT2A and MTAP are key enzymes in methionine metabolism, the dual inhibition of MAT2A and MTAP disrupts methionine metabolism and leads to reduced s-adenosylmethionine. Dietary methionine restriction further boosts the combined anti-tumor efficacy of MTAP depletion/inhibition and PARPi. Most importantly, in brain metastatic TNBC, due to the natural low methionine environment in the brain, the combination of MTAP depletion/inhibition and PARPi confers significant therapeutic efficacy. Therefore, our findings provide a promising strategy for inhibiting primary or brain metastatic TNBC.

Patients with advanced cancers who either do not experience initial response to or progress while on immune checkpoint inhibitors (ICIs) receive salvage radiotherapy to reduce tumor burden and tumor-related symptoms. Occasionally, some patients experience substantial global tumor regression with a rebound of cytotoxic CD8 + T cells. We have termed the rebound of cytotoxic CD8 + T cells in response to salvage therapy as T cell resilience and examined the underlying mechanisms of resilience. Resilient T cells are enriched for CX3CR1 + CD8 + T cells with low mitochondrial membrane potential, accumulate less reactive oxygen species (ROS), and express more malic enzyme 1 (ME1). ME1 overexpression enhanced the cytotoxicity and expansion of effector CD8 + T cells partially via the type I interferon pathway. ME1 also increased mitochondrial respiration while maintaining the redox state balance. ME1 increased the cytotoxicity of peripheral lymphocytes from patients with advanced cancers. Thus, preserved resilient T cells in patients rebound after salvage therapy and ME1 enhances their resiliency.

Abstract Intraductal carcinoma of the prostate (IDC-P) is a lethal prostate cancer subtype that generally coexists with invasive high-grade prostate acinar adenocarcinoma (PAC) but exhibits distinct biological features compared with concomitant adenocarcinoma. In this study, we performed whole-exome, RNA, and DNA-methylation sequencing of IDC-P, concurrent invasive high-grade PAC lesions, and adjacent normal prostate tissues isolated from 22 radical prostatectomy specimens. Three evolutionary patterns of concurrent IDC-P and PAC were identified: early divergent, late divergent, and clonally distant. In contrast to those with a late divergent evolutionary pattern, tumors with clonally distant and early divergent evolutionary patterns showed higher genomic, epigenomic, transcriptional, and pathologic heterogeneity between IDC-P and PAC. Compared with coexisting PAC, IDC-P displayed increased expression of adverse prognosis–associated genes. Survival analysis based on an independent cohort of 505 patients with metastatic prostate cancer revealed that IDC-P carriers with lower risk International Society of Urological Pathology (ISUP) grade 1–4 adenocarcinoma displayed a castration-resistant free survival as poor as those with the highest risk ISUP grade 5 tumors that lacked concurrent IDC-P. Furthermore, IDC-P exhibited robust cell-cycle progression and androgen receptor activities, characterized by an enrichment of cellular proliferation–associated master regulators and genes involved in intratumoral androgen biosynthesis. Overall, this study provides a molecular groundwork for the aggressive behavior of IDC-P and could help identify potential strategies to improve treatment of IDC-P. Significance: The genomic, transcriptomic, and epigenomic characterization of concurrent intraductal carcinoma and adenocarcinoma of the prostate deepens the biological understanding of this lethal disease and provides a genetic basis for developing targeted therapies.

AbstractIn this overview, we describe important contributions from the Antibacterial Resistance Leadership Group (ARLG) to patient care, clinical trials design, and mentorship while outlining future priorities. The ARLG research agenda is focused on 3 key areas: gram-positive infections, gram-negative infections, and diagnostics. The ARLG has developed an innovative approach to clinical trials design, the desirability of outcome ranking (DOOR), which uses an ordinal measure of global outcome to assess both benefits and harms. DOOR was initially applied to observational studies to determine optimal dosing of vancomycin for methicillin-resistant Staphylcococcus aureus bacteremia and the efficacy of ceftazidime-avibactam versus colistin for the treatment of carbapenem-resistant Enterobacterales infection. DOOR is being successfully applied to the analysis of interventional trials and, in collaboration with the US Food and Drug Administration (FDA), for use in registrational trials. In the area of diagnostics, the ARLG developed Master Protocol for Evaluating Multiple Infection Diagnostics (MASTERMIND), an innovative design that allows simultaneous testing of multiple diagnostic platforms in a single study. This approach will be used to compare molecular assays for the identification of fluoroquinolone-resistant Neisseria gonorrhoeae (MASTER GC) and to compare rapid diagnostic tests for bloodstream infections. The ARLG has initiated a first-in-kind randomized, double-blind, placebo-controlled trial in participants with cystic fibrosis who are chronically colonized with Pseudomonas aeruginosa to assess the pharmacokinetics and antimicrobial activity of bacteriophage therapy. Finally, an engaged and highly trained workforce is critical for continued and future success against antimicrobial drug resistance. Thus, the ARLG has developed a robust mentoring program targeted to each stage of research training to attract and retain investigators in the field of antimicrobial resistance research.

Abstract Addressing the treatment and prevention of antibacterial-resistant gram-negative bacterial infections is a priority area of the Antibacterial Resistance Leadership Group (ARLG). The ARLG has conducted a series of observational studies to define the clinical and molecular global epidemiology of carbapenem-resistant and ceftriaxone-resistant Enterobacterales, carbapenem-resistant Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii, with the goal of optimizing the design and execution of interventional studies. One ongoing ARLG study aims to better understand the impact of fluoroquinolone-resistant gram-negative gut bacteria in neutropenic patients, which threatens to undermine the effectiveness of fluoroquinolone prophylaxis in these vulnerable patients. The ARLG has conducted pharmacokinetic studies to inform the optimal dosing of antibiotics that are important in the treatment of drug-resistant gram-negative bacteria, including oral fosfomycin, intravenous minocycline, and a combination of intravenous ceftazidime-avibactam and aztreonam. In addition, randomized clinical trials have assessed the safety and efficacy of step-down oral fosfomycin for complicated urinary tract infections and single-dose intravenous phage therapy for adult patients with cystic fibrosis who are chronically colonized with P. aeruginosa in their respiratory tract. Thus, the focus of investigation in the ARLG has evolved from improving understanding of drug-resistant gram-negative bacterial infections to positively affecting clinical care for affected patients through a combination of interventional pharmacokinetic and clinical studies, a focus that will be maintained moving forward.

Abstract The advancement of infectious disease diagnostics, along with studies devoted to infections caused by gram-negative and gram-positive bacteria, is a top scientific priority of the Antibacterial Resistance Leadership Group (ARLG). Diagnostic tests for infectious diseases are rapidly evolving and improving. However, the availability of rapid tests designed to determine antibacterial resistance or susceptibility directly in clinical specimens remains limited, especially for gram-negative organisms. Additionally, the clinical impact of many new tests, including an understanding of how best to use them to inform optimal antibiotic prescribing, remains to be defined. This review summarizes the recent work of the ARLG toward addressing these unmet needs in the diagnostics field and describes future directions for clinical research aimed at curbing the threat of antibiotic-resistant bacterial infections.

Abstract Cytotoxic T lymphocytes (CTL) are indispensable in anti-tumor immunity. Although CTLs are prone to exhaustion in patients with advanced cancer, T cell resiliency explains the presence of tumor-reactive CTLs that are less exhausted, capable of cytolytic function, expansion, and rebound in response to immunotherapy to reject metastatic malignancies. However, the features of resilient T cells have not been clearly defined. In this report, we demonstrate that peripheral CX3CR1+ CD8+ T cells with low mitochondrial membrane potential rebounded CTL function quickly after radiation therapy in patients with large tumor burden portraying their functional resiliency. Furthermore, CX3CR1+ CD8+ T cell with low, but not high, mitochondrial membrane potential are highly cytotoxic, accumulate less reactive oxygen species (ROS), and express more Malic enzyme 1 (ME1). ME1 overexpression increases ATP production in a glycolysis-independent manner while concurrently curtailing excessive ROS in activated CD8+ T cells; and expands CX3CR1+NKG7+ effector CD8+ T cells with enhanced cytotoxicity. Importantly, transfection of ME1 mRNA promotes tumoricidal activity in CD8+ T cells from patients with advanced cancers. Our study reveals a mechanism used by CTLs to balance excessive ROS via ME1 to maintain a metabolic and functional resiliency. Modification of ME1 expression in CTLs may be a novel method to improve the efficacy of cancer immunotherapy by preventing T cell exhaustion. Supported by grants from Mayo Clinic Foundation and NIH (R01CA 256927-2)

Abstract Imatinib mesylate (IM) has revolutionized the treatment of gastrointestinal stromal tumor (GIST). However, most patients inevitably acquire IM resistance. Second- and third-line treatments exhibit modest clinical benefits with a median time to disease progression of 4 to 6 months, highlighting the urgency for novel therapeutic approaches. Here, we report that the expression of BCL6, a known oncogenic driver and transcriptional repressor, was significantly induced in GIST cells following IM treatment. Elevated BCL6 levels suppressed apoptosis and contributed to IM resistance. Mechanistically, BCL6 recruited SIRT1 to the TP53 promoter to modulate histone acetylation and transcriptionally repress TP53 expression. The reduction in p53 subsequently attenuated cell apoptosis and promoted tolerance of GIST cells to IM. Concordantly, treatment of GIST cells showing high BCL6 expression with a BCL6 inhibitor, BI-3802, conferred IM sensitivity. Furthermore, BI-3802 showed striking synergy with IM in IM-responsive and IM-resistant GIST cells in vitro and in vivo. Thus, these findings reveal a role for BCL6 in IM resistance and suggest that a combination of BCL6 inhibitors and IM could be a potentially effective treatment for GIST. Significance: BCL6 drives resistance to imatinib by inhibiting p53-mediated apoptosis and can be targeted in combination with imatinib to synergistically suppress tumor growth, providing a therapeutic strategy for treating gastrointestinal stromal tumor.