Kanti et al. report that adipose triglyceride lipase, the rate-limiting enzyme for intracellular lipolysis, is critical for club cell–driven regeneration of bronchiolar epithelia in mice. In the cover image, an electron micrograph of an Atgl-KO/cTg club cell shows substantial lipid accumulation within the intracellular lipid droplets.
Macrophages play a crucial role in the inflammatory response to the human stomach pathogen Helicobacter pylori, which infects half of the world’s population and causes gastric cancer. Recent studies have highlighted the importance of macrophage immunometabolism in their activation state and function. We have demonstrated that the cysteine-producing enzyme, cystathionine g-lyase (CTH), is upregulated in humans and mice with H. pylori infection. Here we show that induction of CTH in macrophages by H. pylori promotes persistent inflammation. Cth–/– mice have reduced macrophage and T-cell activation in H. pylori-infected tissues, an altered metabolome, and decreased enrichment of immune-associated gene networks, culminating in decreased H. pylori-induced-gastritis. CTH is downstream of the proposed anti-inflammatory molecule, S-adenosylmethionine (SAM). While Cth–/– mice exhibit gastric SAM accumulation, WT mice treated with SAM did not display protection against H. pylori-induced inflammation. Instead, we demonstrate that Cth-deficient macrophages exhibit alterations in the proteome, decreased NF-kB activation, diminished expression of macrophage activation markers, and impaired oxidative phosphorylation and glycolysis. Thus, through altering cellular respiration, CTH is a key enhancer of macrophage activation contributing to a pathogenic inflammatory response that is the universal precursor for the development of H. pylori-induced gastric disease.
Yvonne L. Latour, Johanna C. Sierra, Jordan L. Finley, Mohammad Asim, Daniel P. Barry, Margaret M. Allaman, Thaddeus M. Smith, Kara M. McNamara, Paula B. Luis, Claus Schneider, Justin Jacobse, Jeremy A. Goettel, M. Wade Calcutt, Kristie L. Rose, Kevin L Schey, Ginger L. Milne, Alberto G. Delgado, M. Blanca Piazuelo, Bindu D. Paul, Solomon Snyder, Alain P. Gobert, Keith T. Wilson
Cyclophosphamide (CPA) and doxorubicin (DOX) are key components of chemotherapy for triple-negative breast cancer (TNBC) although suboptimal outcomes are commonly associated with drug resistance and/or intolerable side-effects. Through an approach combining high-throughput screening and chemical modification, we developed CN06 as a dual activator of the constitutive androstane receptor (CAR) and nuclear factor erythroid 2-related factor 2 (Nrf2). CN06 enhances CAR-induced bioactivation of CPA (a prodrug) by provoking hepatic expression of CYP2B6, while repressing DOX-induced cytotoxicity in cardiomyocytes in vitro via stimulating Nrf2-antioxidant signaling. Utilizing a multicellular co-culture model incorporating human primary hepatocytes, TNBC cells, and cardiomyocytes, we show that CN06 increased CPA/DOX-mediated TNBC cell death via CAR-dependent CYP2B6 induction and subsequent conversion of CPA to its active metabolite 4-hydroxy-CPA, while protecting against DOX-induced cardiotoxicity by selectively activating Nrf2-antioxidant signaling in cardiomyocytes but not in TNBC cells. Further, CN06 preserves the viability and function of human iPSC-derived cardiomyocytes by modulating antioxidant defenses, decreasing apoptosis, and enhancing the kinetics of contraction and relaxation. Collectively, our findings identify CAR and Nrf2 as novel combined therapeutic targets whereby CN06 holds the potential to improve the efficacy:toxicity ratio of CPA/DOX-containing chemotherapy.
Sydney Stern, Dongdong Liang, Linhao Li, Ritika Kurian, Caitlin Lynch, Srilatha Sakamuru, Scott Heyward, Junran Zhang, Kafayat Ajoke Kareem, Young Wook Chun, Ruili Huang, Menghang Xia, Charles C. Hong, Fengtian Xue, Hongbing Wang
BACKGROUND. Sudden cardiac death (SCD) remains a worldwide public health problem in need of better noninvasive predictive tools. Current guidelines for primary preventive SCD therapies such as implantable cardioverter defibrillators (ICDs) are based on left ventricular ejection fraction (LVEF), but these are imprecise with fewer than 5% of ICDs delivering life-saving therapy per year. Impaired cardiac metabolism and ATP depletion cause arrhythmias in experimental models, but a link between arrhythmias and cardiac energetic abnormalities in people has not been explored, nor the potential for metabolically predicting clinical SCD risk. METHODS. We prospectively measured myocardial energy metabolism noninvasively with phosphorus magnetic resonance spectroscopy in patients with no history of significant arrhythmias prior to scheduled ICD implantation for primary prevention in the setting of reduced LVEF (≤35%). RESULTS. By two different analyses, low myocardial ATP significantly predicted the composite of subsequent appropriate ICD firings for life-threatening arrhythmias and cardiac death over ~10 years. Life-threatening arrhythmia risk was ~3-fold higher in low ATP patients and independent of established risk factors including LVEF. In patients with normal ATP, rates of appropriate ICD firings were several-fold lower than reported rates of ICD complications and inappropriate firings. CONCLUSION. These first data linking in vivo myocardial ATP depletion and subsequent significant arrhythmic events in people suggest an energetic component to clinical life-threatening ventricular arrhythmogenesis. The findings support investigation of metabolic strategies that limit ATP loss to treat or prevent life-threatening cardiac arrhythmias and herald non-invasive metabolic imaging as a complementary SCD risk stratification tool. TRIAL REGISTRATION. NCT00181233. FUNDING. This work was supported by DW Reynolds Foundation, the National Institutes of Health (grants HL61912, HL056882, HL103812, HL132181, HL140034), and the Russell H. Morgan (P.A.B.) and Clarence Doodeman (R.G.W.) Endowments at Johns Hopkins.
T. Jake Samuel, Shenghan Lai, Michael Schär, Katherine C. Wu, Angela M. Steinberg, An-Chi Wei, Mark Anderson, Gordon F. Tomaselli, Gary Gerstenblith, Paul A. Bottomley, Robert G. Weiss
Nemaline Myopathy (NM) is the most common congenital myopathy, characterized by extreme weakness of the respiratory, limb, and facial muscles. Pathogenic variants in Tropomyosin 2 (TPM2), which encodes a skeletal muscle specific actin binding protein essential for sarcomere function, cause a spectrum of musculoskeletal disorders that include NM as well as Cap Myopathy, congenital fiber type disproportion, and distal arthrogryposis (DA). The in vivo pathomechanisms underlying TPM2-related disorders are unknown, so we expressed a series of dominant, pathogenic TPM2 variants in Drosophila embryos and found four variants significantly affected muscle development and muscle function. Transient overexpression of the four variants also disrupted the morphogenesis of mouse myotubes in vitro, and negatively affected zebrafish muscle development in vivo. We used transient overexpression assays in zebrafish to characterize two novel TPM2 variants and one recurring variant that we identified in DA patients (V129A, E139K, A155T), and found these variants caused musculoskeletal defects similar to those of known pathogenic variants. The consistency of musculoskeletal phenotypes in our assays correlated with the severity of clinical phenotypes observed in our DA patients, suggesting disrupted myogenesis is a novel pathomechanism of TPM2 disorders, and that our myogenic assays can predict the clinical severity of TPM2 variants.
Jennifer McAdow, Shuo Yang, Tiffany Ou, Gary Huang, Matthew B. Dobbs, Christina A. Gurnett, Michael J. Greenberg, Aaron N. Johnson
In situ vaccination has demonstrated the feasibility of priming local immunity for systemic antitumor responses. Although direct intratumoral delivery of adjuvant is the mainstay, tumor-draining lymph nodes (TDLNs) also play essential roles in antitumor immunity. We report that directing an adjuvant to both tumors and TDLNs during in situ vaccination can induce robust antitumor responses. Conventional intratumoral dosing leads to tumor-limited delivery of agents; however, delivery to both tumors and TDLNs can be ensured through a micellar formation. The peritumoral delivery of micellar MEDI9197 (mcMEDI), a toll-like receptor 7/8 agonist, induced significantly stronger innate and adaptive immune responses than those on conventional dosing. Optimal dosing was crucial because excessive or insufficient accumulation of the adjuvant in the TDLNs compromised therapeutic efficacy. The combination of local mcMEDI therapy significantly improved the efficacy of systemic anti-programmed death receptor-1 therapy. These data suggest that rerouting adjuvants to tumors and TDLNs can augment the therapeutic efficacy of in situ vaccination.
Moonkyoung Jeong, Heegon Kim, Junyong Yoon, Dong-Hyun Kim, Ji-Ho Park
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