Citations

Tissue fibrosis represents an increasing cause of morbidity and mortality worldwide, with fibroblast‐derived myofibroblasts playing an essential pathogenic role. Myofibroblasts are characterized by their increased expression of smooth muscle actin (α‐SMA), and contribute to tissue fibrosis through their increased abundance, matrix deposition and tissue contraction. Unlike in physiological wound repair, where fibroblast activation is spontaneously reversible, the fibroblast activation associated with pathological fibrosis is perpetuated, and fibroblasts maintain their activated phenotype even after the initial injury has been resolved. Previous studies have shown that aberrant epigenetic signaling may drive sustained fibroblast activation during fibrosis and several small‐molecule epigenetic modifiers have been shown to be effective in protecting against fibrosis in various animal models, however no systematic effort has been reported to identify epigenetic small molecule regulators of myofibroblast activation. Here we screened a library of 98 well‐annotated epigenetic modifying compounds from Mayo Clinic's collaboration with Nanosyn (Santa Clara, CA) for their ability to inhibit fibroblast to myofibroblast activation. To analyze compound effects, we designed a high‐content image‐based screening method to quantify α‐SMA expression, organization, and area coverage. For each metric we calculated an independent Z‐score, and to identify which compounds most effectively blocked myofibroblast activation we created a robust, multiparametric “Deep Z Analysis” which stacked together individual Z‐scores. In the initial screen each compound was run in triplicate using three concentrations (0.5, 2.5, and 10 μM). Screen hits were defined by any compound which displayed an estimated IC50 < 2.5μM, resulting in a hit rate of 12.2%. These 12 hits were then validated for their efficacy in lung fibroblasts derived from patients with idiopathic pulmonary fibrosis. In support of our overall screening approach, among the primary screen hits were compounds previously shown to be antifibrotic, including: bromodomain inhibitors JQ1 and CPI‐0610, DNA methyl transferase inhibitor azacitidine, and Poly (ADP‐ribose) Polymerase (PARP) inhibitor ABT‐888. While several epigenetic therapies are already approved by the FDA for cancer treatment, no epigenetic drugs for the treatment of fibrotic diseases have reached the clinic. Our approach will help identify epigenetic modifiers attractive for further detailed research, with a long term goal of defining new targets to move forward towards eventual therapies for lung fibrosis.

Abstract During aging, muscle gradually undergoes sarcopenia, the loss of function associated with loss of mass, strength, endurance, and oxidative capacity. However, the 3D structural alterations of mitochondria associated with aging in skeletal muscle and cardiac tissues are not well described. Although mitochondrial aging is associated with decreased mitochondrial capacity, the genes responsible for the morphological changes in mitochondria during aging are poorly characterized. We measured changes in mitochondrial morphology in aged murine gastrocnemius, soleus, and cardiac tissues using serial block‐face scanning electron microscopy and 3D reconstructions. We also used reverse transcriptase‐quantitative PCR, transmission electron microscopy quantification, Seahorse analysis, and metabolomics and lipidomics to measure changes in mitochondrial morphology and function after loss of mitochondria contact site and cristae organizing system (MICOS) complex genes, Chchd3 , Chchd6 , and Mitofilin . We identified significant changes in mitochondrial size in aged murine gastrocnemius, soleus, and cardiac tissues. We found that both age‐related loss of the MICOS complex and knockouts of MICOS genes in mice altered mitochondrial morphology. Given the critical role of mitochondria in maintaining cellular metabolism, we characterized the metabolomes and lipidomes of young and aged mouse tissues, which showed profound alterations consistent with changes in membrane integrity, supporting our observations of age‐related changes in muscle tissues. We found a relationship between changes in the MICOS complex and aging. Thus, it is important to understand the mechanisms that underlie the tissue‐dependent 3D mitochondrial phenotypic changes that occur in aging and the evolutionary conservation of these mechanisms between Drosophila and mammals.

Abstract Background Genicular nerve radiofrequency ablation (GNRFA) is an effective treatment for chronic knee pain. However, there has been minimal investigation of real-world, long-term outcomes and factors that predict treatment success after GNRFA. Objectives To evaluate the effectiveness of GNRFA for chronic knee pain in a real-world population and identify predictive factors. Methods Consecutive patients who underwent GNRFA at a tertiary academic center were identified. Demographic, clinical, and procedural characteristics were collected from the medical record. Outcome data were numeric rating scale (NRS) pain reduction and Patient Global Impression of Change (PGIC). Data were collected by standardized telephone survey. Predictors of success were evaluated with logistic and Poisson regression analyses. Results Of the 226 total patients identified, 134 (65.6 ± 12.7; 59.7% female) were successfully contacted and analyzed, with a mean follow-up time of 23.3 ± 11.0 months. Of those, 47.8% (n = 64; 95% CI: 39.5%–56.2%) and 61.2% (n = 82; 95% CI: 52.7%–69.0%) reported ≥50% NRS score reduction and ≥2-point NRS score reduction, respectively, and 59.0% (n = 79; 95% CI: 50.5%–66.9%) reported “much improved” on the PGIC questionnaire. Factors associated with a greater likelihood of treatment success (P &lt; .05) were higher Kellgren–Lawrence osteoarthritis grade (2–4 vs 0–1); no baseline opioid, antidepressant, or anxiolytic medication use; and &gt;3 nerves targeted. Conclusion In this real-world cohort, approximately half of the participants experienced clinically meaningful improvements in knee pain after GNRFA at an average follow-up time of nearly 2 years. Factors associated with higher likelihood of treatment success were more advanced osteoarthritis (Kellgren–Lawrence Grade 2–4); no opioid, antidepressant, or anxiolytic medication use; and &gt;3 nerves targeted.

Hypoplastic left heart syndrome (HLHS) is a severe congenital heart disease (CHD) with a likely oligogenic etiology, but our understanding of the genetic complexities and pathogenic mechanisms leading to HLHS is limited. We performed whole genome sequencing (WGS) on 183 HLHS patient-parent trios to identify candidate genes, which were functionally tested in the Drosophila heart model. Bioinformatic analysis of WGS data from an index family of a HLHS proband born to consanguineous parents prioritized 9 candidate genes with rare, predicted damaging homozygous variants. Of them, cardiac-specific knockdown (KD) of mitochondrial MICOS complex subunit dCHCHD3/6 resulted in drastically compromised heart contractility, diminished levels of sarcomeric actin and myosin, reduced cardiac ATP levels, and mitochondrial fission-fusion defects. These defects were similar to those inflicted by cardiac KD of ATP synthase subunits of the electron transport chain (ETC), consistent with the MICOS complex’s role in maintaining cristae morphology and ETC assembly. Five additional HLHS probands harbored rare, predicted damaging variants in CHCHD3 or CHCHD6 . Hypothesizing an oligogenic basis for HLHS, we tested 60 additional prioritized candidate genes from these patients for genetic interactions with CHCHD3/6 in sensitized fly hearts. Moderate KD of CHCHD3/6 in combination with Cdk12 (activator of RNA polymerase II), RNF149 ( goliath , E3 ubiquitin ligase), or SPTBN1 ( β-Spectrin, scaffolding protein) caused synergistic heart defects, suggesting the likely involvement of diverse pathways in HLHS. Further elucidation of novel candidate genes and genetic interactions of potentially disease-contributing pathways is expected to lead to a better understanding of HLHS and other CHDs.

As part of an ongoing effort to develop a drug targeting the type 1 cholecystokinin receptor (CCK1R) to help prevent and/or treat obesity, we recently performed a high throughput screening effort of small molecules seeking candidates that enhanced the action of the natural agonist, CCK, thus acting as positive allosteric modulators without exhibiting intrinsic agonist action. Such probes would be expected to act in a temporally finite way to enhance CCK action to induce satiety during and after a meal and potentially even modulate activity at the CCK1R in a high cholesterol environment present in some obese patients. The current work focuses on the best scaffold, representing tetracyclic molecules identified through high throughput screening we previously reported. Extensive characterization of the two top “hits” from the previous effort demonstrated them to fulfill the desired pharmacologic profile. We undertook analog-by-catalog expansion of this scaffold using 65 commercially available analogs. In this effort, we were able to eliminate an off-target effect observed for this scaffold while retaining its activity as a positive allosteric modulator of CCK1R in both normal and high cholesterol membrane environments. These insights should be useful in the rational medicinal chemical enhancement of this scaffold and in the future development of candidates to advance to pre-clinical proof-of-concept and to clinical trials.

The endoplasmic reticulum (ER) is an intracellular organelle that fosters the correct folding of linear polypeptides and proteins, a process tightly governed by the ER‐resident enzymes and chaperones. Failure to shape the proper 3‐dimensional architecture of proteins culminates in the accumulation of misfolded or unfolded proteins within the ER, disturbs ER homeostasis, and leads to canonically defined ER stress. Recent studies have elucidated that cellular perturbations, such as lipotoxicity, can also lead to ER stress. In response to ER stress, the unfolded protein response (UPR) is activated to reestablish ER homeostasis (“adaptive UPR”), or, conversely, to provoke cell death when ER stress is overwhelmed and sustained (“maladaptive UPR”). It is well documented that ER stress contributes to the onset and progression of multiple hepatic pathologies including NAFLD, alcohol‐associated liver disease, viral hepatitis, liver ischemia, drug toxicity, and liver cancers. Here, we review key studies dealing with the emerging role of ER stress and the UPR in the pathophysiology of liver diseases from cellular, murine, and human models. Specifically, we will summarize current available knowledge on pharmacological and non‐pharmacological interventions that may be used to target maladaptive UPR for the treatment of nonmalignant liver diseases.

Antibiotic resistance, particularly to carbapenems, is of increasing concern in Bacteroides fragilis . Carbapenem resistance in B. fragilis is most often mediated by the activation of chromosomally encoded metallo-β-lactamase cfiA by the presence of an upstream insertion sequence (IS).