Mitochondrial Calcium Signaling Regulates Branched-Chain Amino Acid Catabolism in Fibrolamellar Carcinoma.

Metabolic adaptations in response to changes in energy supply and demand are essential for survival. The mitochondrial calcium uniporter coordinates metabolic homeostasis by regulating TCA cycle activation, mitochondrial fatty acid oxidation and cellular calcium signaling. However, a comprehensive analysis of uniporter-regulated mitochondrial metabolic pathways has remained unexplored. Here, we investigate the metabolic consequences of uniporter loss- and gain-of-function, and identify a key transcriptional regulator that mediates these effects. Using gene expression profiling and proteomic, we find that loss of uniporter function increases the expression of proteins in the branched-chain amino acid (BCAA) catabolism pathway. Activity is further augmented through phosphorylation of the enzyme that catalyzes this pathway's committed step. Conversely, in the liver cancer fibrolamellar carcinoma (FLC)-which we demonstrate to have high mitochondrial calcium levels- expression of BCAA catabolism enzymes is suppressed. We also observe uniporter-dependent suppression of the transcription factor KLF15, a master regulator of liver metabolic gene expression, including those involved in BCAA catabolism. Notably, loss of uniporter activity upregulates KLF15, along with its transcriptional target ornithine transcarbamylase (OTC), a component of the urea cycle, suggesting that uniporter hyperactivation may contribute to the hyperammonemia observed in FLC patients. Collectively, we establish that FLC has increased mitochondrial calcium levels, and identify an important role for mitochondrial calcium signaling in metabolic adaptation through the transcriptional regulation of metabolism.

Large-Scale Telemedicine Implementation for Outpatient Clinicians: Results From a Pandemic-Adapted Learning Collaborative.

Learning collaboratives are seldom used outside of health care quality improvement. We describe a condensed, 10-week learning collaborative ("Telemedicine Hack") that facilitated telemedicine implementation for outpatient clinicians early in the COVID-19 pandemic. Live attendance averaged 1688 participants per session. Of 1005 baseline survey respondents, 57% were clinicians with one-third identifying as from a racial/ethnic minoritized group. Practice characteristics included primary care (71%), rural settings (51%), and community health centers (28%). Of three surveys, a high of 438 (81%) of 540 clinicians had billed ≥1 video-based telemedicine visit. Our learning collaborative "sprint" is a promising model for scaling knowledge during emergencies and addressing health inequities.

Burnout, Compassion Fatigue, and the Long Haul of Caring for Long COVID.

The current landscape of clinician burnout is prompting the need for our health care system to revise its approach toward complex conditions such as long coronavirus disease (COVID), myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and other postinfectious fatiguing illnesses (PIFIs). We discuss our efforts here at Family Health Center of San Diego (FHCSD) to help share insight and glean perspective from clinicians who have participated in our Centers for Disease Control and Prevention (CDC)-funded 3-year continuing professional development initiative. The Long COVID and Fatiguing Illness Recovery Program uses multidisciplinary team-based case consultation and peer-to-peer sharing of emerging best and promising practices (ie, teleECHO [Extension for Community Healthcare Outcomes]) to support the management of complex cases associated with long COVID, ME/CFS, and other PIFIs. We believe that this perspective captures a key moment in the trajectory of postpandemic clinician burnout and prompts further reflection and action from the health care system to improve clinician- and patient-level outcomes related to the care of patients with postinfectious fatiguing illnesses.

Discovery of a Cushing's syndrome protein kinase A mutant that biases signaling through type I AKAPs.

Adrenal Cushing's syndrome is a disease of cortisol hypersecretion often caused by mutations in protein kinase A catalytic subunit (PKAc). Using a personalized medicine screening platform, we discovered a Cushing's driver mutation, PKAc-W196G, in ~20% of patient samples analyzed. Proximity proteomics and photokinetic imaging reveal that PKAcW196G is unexpectedly distinct from other described Cushing's variants, exhibiting retained association with type I regulatory subunits (RI) and their corresponding A kinase anchoring proteins (AKAPs). Molecular dynamics simulations predict that substitution of tryptophan-196 with glycine creates a 653-cubic angstrom cleft between the catalytic core of PKAcW196G and type II regulatory subunits (RII), but only a 395-cubic angstrom cleft with RI. Endocrine measurements show that overexpression of RIα or redistribution of PKAcW196G via AKAP recruitment counteracts stress hormone overproduction. We conclude that a W196G mutation in the kinase catalytic core skews R subunit selectivity and biases AKAP association to drive Cushing's syndrome.

cAMP signaling: a remarkably regional affair.

Louis Pasteur once famously said 'in the fields of observation chance favors only the prepared mind'. Much of chance is being in the right place at the right time. This is particularly true in the crowded molecular environment of the cell where being in the right place is often more important than timing. Although Brownian motion argues that enzymes will eventually bump into substrates, this probability is greatly enhanced if both molecules reside in the same subcellular compartment. However, activation of cell signaling enzymes often requires the transmission of chemical signals from extracellular stimuli to intracellular sites of action. This review highlights new developments in our understanding of cAMP generation and the 3D utilization of this second messenger inside cells.

Recruitment of BAG2 to DNAJ-PKAc scaffolds promotes cell survival and resistance to drug-induced apoptosis in fibrolamellar carcinoma.

The DNAJ-PKAc fusion kinase is a defining feature of fibrolamellar carcinoma (FLC). FLC tumors are notoriously resistant to standard chemotherapies, with aberrant kinase activity assumed to be a contributing factor. By combining proximity proteomics, biochemical analyses, and live-cell photoactivation microscopy, we demonstrate that DNAJ-PKAc is not constrained by A-kinase anchoring proteins. Consequently, the fusion kinase phosphorylates a unique array of substrates, including proteins involved in translation and the anti-apoptotic factor Bcl-2-associated athanogene 2 (BAG2), a co-chaperone recruited to the fusion kinase through association with Hsp70. Tissue samples from patients with FLC exhibit increased levels of BAG2 in primary and metastatic tumors. Furthermore, drug studies implicate the DNAJ-PKAc/Hsp70/BAG2 axis in potentiating chemotherapeutic resistance. We find that the Bcl-2 inhibitor navitoclax enhances sensitivity to etoposide-induced apoptosis in cells expressing DNAJ-PKAc. Thus, our work indicates BAG2 as a marker for advanced FLC and a chemotherapeutic resistance factor in DNAJ-PKAc signaling scaffolds.

Training the healthcare workforce: the global experience with telementorship for hepatitis B and hepatitis C.

BACKGROUND: Telementorship has emerged as an innovative strategy to decentralise medical knowledge and increase healthcare capacity across a wide range of disease processes. We report the global experience with telementorship to support healthcare workers delivering hepatitis B virus (HBV) and hepatitis C virus (HCV) care and treatment. METHODS: In early 2020, we conducted a survey of HBV and HCV telementorship programmes, followed by an in-depth interview with programme leads. Programmes were eligible to participate if they were located outside of the United States (U.S.), focused on support to healthcare workers in management of HBV and/or HCV, and were affiliated with or maintained adherence to the Project ECHO model, a telementorship programme pioneered at the University of New Mexico. One programme in the U.S., focused on HCV treatment in the Native American community, was purposively sampled and invited to participate. Surveys were administered online, and all qualitative interviews were performed remotely. Descriptive statistics were calculated for survey responses, and qualitative interviews were assessed for major themes. RESULTS: Eleven of 18 eligible programmes completed the survey and follow up interview. Sixty-four percent of programmes were located at regional academic medical centers. The majority of programmes (64%) were led by hepatologists. Most programmes (82%) addressed both HBV and HCV, and the remainder focused on HCV only. The median number of participating clinical spoke sites per programme was 22, and most spoke site participants were primary care providers. Most ECHO sessions were held monthly (36%) or bimonthly (27%), with sessions ranging from 45 min to 2 h in length. Programme leaders identified collective learning, empowerment and collaboration to be key strengths of their telementorship programme, while insufficient funding and a lack of protected time for telementorship leaders and participants were identified as major barriers to success. CONCLUSION: The Project ECHO model for telementorship can be successfully implemented across high and low-and-middle-income countries to improve provider knowledge and experience in management of viral hepatitis. There is a tremendous opportunity to further expand upon the existing experience with telementorship to support non-specialist healthcare workers and promote elimination of viral hepatitis.

A technology-enabled multi-disciplinary team-based care model for the management of Long COVID and other fatiguing illnesses within a federally qualified health center: protocol for a two-arm, single-blind, pragmatic, quality improvement professional cluster randomized controlled trial.

BACKGROUND: The clinical burden of Long COVID, myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), and other post-infectious fatiguing illnesses (PIFI) is increasing. There is a critical need to advance understanding of the effectiveness and sustainability of innovative approaches to clinical care of patients having these conditions. METHODS: We aim to assess the effectiveness of a Long COVID and Fatiguing Illness Recovery Program (LC&FIRP) in a two-arm, single-blind, pragmatic, quality improvement, professional cluster, randomized controlled trial in which 20 consenting clinicians across primary care clinics in a Federally Qualified Health Center system in San Diego, CA, will be randomized at a ratio of 1:1 to either participate in (1) weekly multi-disciplinary team-based case consultation and peer-to-peer sharing of emerging best practices (i.e., teleECHO (Extension for Community Healthcare Outcomes)) with monthly interactive webinars and quarterly short courses or (2) monthly interactive webinars and quarterly short courses alone (a control group); 856 patients will be assigned to participating clinicians (42 patients per clinician). Patient outcomes will be evaluated according to the study arm of their respective clinicians. Quantitative and qualitative outcomes will be measured at 3- and 6-months post-baseline for clinicians and every 3-months post assignment to a participating clinician for patients. The primary patient outcome is change in physical function measured using the Patient-Reported Outcomes Measurement Information System (PROMIS)-29. Analyses of differences in outcomes at both the patient and clinician levels will include a linear mixed model to compare change in outcomes from baseline to each post-baseline assessment between the randomized study arms. A concurrent prospective cohort study will compare the LC&FIRP patient population to the population enrolled in a university health system. Longitudinal data analysis approaches will allow us to examine differences in outcomes between cohorts. DISCUSSION: We hypothesize that weekly teleECHO sessions with monthly interactive webinars and quarterly short courses will significantly improve clinician- and patient-level outcomes compared to the control group. This study will provide much needed evidence on the effectiveness of a technology-enabled multi-disciplinary team-based care model for the management of Long COVID, ME/CFS, and other PIFI within a federally qualified health center. TRIAL REGISTRATION: ClinicalTrials.gov, NCT05167227 . Registered on December 22, 2021.

Training the healthcare workforce to support task-shifting and viral hepatitis elimination: a global review of English language online trainings and in-person workshops for management of hepatitis B and C infection.

BACKGROUND: Achieving World Health Organization (WHO) targets for viral hepatitis elimination will require simplification and decentralisation of care, supported through task-shifting and training of non-specialist frontline healthcare workers. To inform development of national health worker trainings in viral hepatitis, we review and summarise available online and workshop trainings for management of hepatitis B virus (HBV) and hepatitis C virus (HCV). METHODS: We performed a systematic search of PubMed, Embase, Web of Science, conference abstracts, and grey literature using Google to identify online and in-person workshop trainings for health workers focused on HBV and/or HCV. Additional trainings were identified through a WHO regional network. We included online trainings written in English and in-person workshops developed for low-and-middle-income countries (LMICs). Available curricula are summarised together with key operational features (e.g. training length, year developed/updated, developing institution) and programmatic features (e.g. content, mechanism for self-assessment, use of clinical case studies). RESULTS: A total of 30 trainings met our inclusion criteria (10 online trainings; 20 in-person workshops). 50% covered both HBV and HCV, 13% HBV alone and 37% HCV alone. Among online trainings, only 2 (20%) were specifically developed or adapted for LMICs; 70% covered all aspects of hepatitis care, including prevention, assessment, and treatment; 9 (90%) included guidance on when to refer to specialists, and 6 (60%) included modules on management in specific populations (e.g., people who inject drugs [PWID], prisoners, and children). Online trainings used different formats including text-based modules, narrated slide-sets, and interactive web-based modules. Most workshops (95%) were targeted towards non-specialty providers, and 50% were an integral part of a national strategy for viral hepatitis elimination. Workshop length ranged from several hours to multiple sessions over the course of months, and many were part of a blended educational model, which included other opportunities for ongoing learning (e.g., telementorship). CONCLUSION: This compendium of online and in-person workshop trainings for HBV and HCV is a useful resource for national hepatitis programmes developing training curricula for non-specialists. Additional online training curricula are needed for use in LMICs, and additional materials are needed to address management challenges in key populations, such as PWID.

Recruitment of BAG2 to DNAJ-PKAc scaffolds promotes cell survival and resistance to drug-induced apoptosis in fibrolamellar carcinoma.

The DNAJ-PKAc fusion kinase is a defining feature of the adolescent liver cancer fibrolamellar carcinoma (FLC). A single lesion on chromosome 19 generates this mutant kinase by creating a fused gene encoding the chaperonin binding domain of Hsp40 (DNAJ) in frame with the catalytic core of protein kinase A (PKAc). FLC tumors are notoriously resistant to standard chemotherapies. Aberrant kinase activity is assumed to be a contributing factor. Yet recruitment of binding partners, such as the chaperone Hsp70, implies that the scaffolding function of DNAJ- PKAc may also underlie pathogenesis. By combining proximity proteomics with biochemical analyses and photoactivation live-cell imaging we demonstrate that DNAJ-PKAc is not constrained by A-kinase anchoring proteins. Consequently, the fusion kinase phosphorylates a unique array of substrates. One validated DNAJ-PKAc target is the Bcl-2 associated athanogene 2 (BAG2), a co-chaperone recruited to the fusion kinase through association with Hsp70. Immunoblot and immunohistochemical analyses of FLC patient samples correlate increased levels of BAG2 with advanced disease and metastatic recurrences. BAG2 is linked to Bcl-2, an anti-apoptotic factor that delays cell death. Pharmacological approaches tested if the DNAJ- PKAc/Hsp70/BAG2 axis contributes to chemotherapeutic resistance in AML12 DNAJ-PKAc hepatocyte cell lines using the DNA damaging agent etoposide and the Bcl-2 inhibitor navitoclax. Wildtype AML12 cells were susceptible to each drug alone and in combination. In contrast, AML12 DNAJ-PKAc cells were moderately affected by etoposide, resistant to navitoclax, but markedly susceptible to the drug combination. These studies implicate BAG2 as a biomarker for advanced FLC and a chemotherapeutic resistance factor in DNAJ-PKAc signaling scaffolds.

Classification of Cushing's syndrome PKAc mutants based upon their ability to bind PKI.

Cushing's syndrome is an endocrine disorder caused by excess production of the stress hormone cortisol. Precision medicine strategies have identified single allele mutations within the PRKACA gene that drive adrenal Cushing's syndrome. These mutations promote perturbations in the catalytic core of protein kinase A (PKAc) that impair autoinhibition by regulatory subunits and compartmentalization via recruitment into AKAP signaling islands. PKAcL205R is found in ∼45% of patients, whereas PKAcE31V, PKAcW196R, and L198insW and C199insV insertion mutants are less prevalent. Mass spectrometry, cellular, and biochemical data indicate that Cushing's PKAc variants fall into two categories: those that interact with the heat-stable protein kinase inhibitor PKI, and those that do not. In vitro activity measurements show that wild-type PKAc and W196R activities are strongly inhibited by PKI (IC50 < 1 nM). In contrast, PKAcL205R activity is not blocked by the inhibitor. Immunofluorescent analyses show that the PKI-binding variants wild-type PKAc, E31V, and W196R are excluded from the nucleus and protected against proteolytic processing. Thermal stability measurements reveal that upon co-incubation with PKI and metal-bound nucleotide, the W196R variant tolerates melting temperatures 10°C higher than PKAcL205. Structural modeling maps PKI-interfering mutations to a ∼20 Šdiameter area at the active site of the catalytic domain that interfaces with the pseudosubstrate of PKI. Thus, Cushing's kinases are individually controlled, compartmentalized, and processed through their differential association with PKI.

Proximity biotinylation to define the local environment of the protein kinase A catalytic subunit in adrenal cells.

Mutant protein kinase A catalytic subunit (PKAc) drives adrenal Cushing's syndrome, though its signaling interactions remain unclear. This protocol details steps to use live-cell proximity labeling to identify subcellular compartments and proteins closely associated with variants of PKAc in human adrenal cells. We include instructions for clonal cell line generation, live biotin labeling of proximal proteins, isolation of biotinylated proteins, and sample processing for proteomic analysis using the biotin ligase miniTurbo with wild-type and mutant PKAc.1,2 For complete details on the use and execution of this protocol, please refer to Omar et al. (2022).3.

Oncogenic PKA signaling increases c-MYC protein expression through multiple targetable mechanisms.

Genetic alterations that activate protein kinase A (PKA) are found in many tumor types. Yet, their downstream oncogenic signaling mechanisms are poorly understood. We used global phosphoproteomics and kinase activity profiling to map conserved signaling outputs driven by a range of genetic changes that activate PKA in human cancer. Two signaling networks were identified downstream of PKA: RAS/MAPK components and an Aurora Kinase A (AURKA)/glycogen synthase kinase (GSK3) sub-network with activity toward MYC oncoproteins. Findings were validated in two PKA-dependent cancer models: a novel, patient-derived fibrolamellar carcinoma (FLC) line that expresses a DNAJ-PKAc fusion and a PKA-addicted melanoma model with a mutant type I PKA regulatory subunit. We identify PKA signals that can influence both de novo translation and stability of the proto-oncogene c-MYC. However, the primary mechanism of PKA effects on MYC in our cell models was translation and could be blocked with the eIF4A inhibitor zotatifin. This compound dramatically reduced c-MYC expression and inhibited FLC cell line growth in vitro. Thus, targeting PKA effects on translation is a potential treatment strategy for FLC and other PKA-driven cancers.

Outcomes of Bariatric Surgery With Concomitant Hiatal Hernia Repair Using an Absorbable Tissue Matrix.

BACKGROUND: Hiatal hernias are a common finding in patients who undergo bariatric surgery with an incidence of about 20% of all bariatric patients. Controversy exists on the utility of a biosynthetic tissue matrix (BTM) usage in combination with crural repair. This study was designed to explore the safety and benefits of the use of a BTM during concomitant hiatal hernia repair with bariatric surgical procedures. METHODS: This was a retrospective chart review of bariatric surgical patients who underwent a concomitant hiatal hernia repair at a single practice at a tertiary academic medical center from January 2014 to February 2019. RESULTS: A total of 420 patients were reviewed. Hiatal BTM reinforcement, recurrence, and postoperative proton pump inhibitor use were reported by type of operation. Recurrence was higher in gastric bypass patients who underwent hiatal hernia repair with suture cruroplasty alone vs. those who also underwent hiatal BTM reinforcement (7.1% vs. 3.7%, P = .52) and significantly higher in gastric sleeve patients who underwent hiatal hernia repair with suture cruroplasty alone vs. those who also underwent hiatal BTM reinforcement (7.1% vs. .5%, P = .01). No patient required reoperation for hiatal hernia recurrence. DISCUSSION: Performing Roux-en-Y gastric bypass or vertical sleeve gastrectomy with concomitant hiatal hernia repair is safe and durable. Employing crural reinforcement with BTM may be of benefit in reducing recurrence rates of hiatal hernia, particularly in sleeve gastrectomy patients.

Barriers and facilitators to implementing a Pharmacist, Physician, and Patient Navigator-Collaborative Care Model (PPP-CCM) to treat hepatitis C among people who inject drugs.

BACKGROUND: Direct-acting antivirals (DAAs) offer an unprecedented opportunity to eliminate hepatitis C virus (HCV) infection, yet barriers among people who inject drugs (PWID) remain. Having pharmacists provide care through collaborative drug therapy agreements (CDTAs) offers a promising solution. We developed and piloted a Pharmacist, Physician, and Patient Navigator-Collaborative Care Model (PPP-CCM) which utilized pharmacists to directly deliver HCV care at community organizations serving PWID. We conducted formative evaluation of the PPP-CCM pilot to characterize implementation experiences. METHODS: The PPP-CCM was implemented from November of 2020 through July of 2022. Formative evaluation team members observed implementation-related meetings and conducted multiple site visits, taking detailed fieldnotes. Fieldnotes were iteratively reviewed to identify barriers and facilitators to implementation and used to inform 7 key informant interviews conducted with programmatic staff at the end of the pilot. All data were analyzed using a Rapid Assessment Process (RAP) guided by the Consolidated Framework for Implementation Research (CFIR). The formative evaluation team shared results with program stakeholders (pharmacists, physicians, and other site staff) to verify and expand on learnings. RESULTS: Evaluation of PPP-CCM revealed 5 themes, encompassing all CFIR domains: 1) PPP-CCM was feasible but challenging to deliver efficiently; 2) the pharmacist role and characteristics (e.g., being flexible, available, and patient-centered) were key to PPP-CCM successes; 3) the PPP-CCM team met challenges engaging patients over time, but some team-based strategies helped; 4) community site characteristics (e.g., existing trusting relationships with PWID and physical space that enabled program visibility) were important contributors; and 5) financial barriers may limit PPP-CCM scale-up and sustainability. CONCLUSION: PPP-CCM is a novel and promising approach to HCV care delivery for PWID who may previously lack engagement in traditional care models, but careful attention needs to be paid to financial barriers to ensure scalability and sustainability.

Insurance-mandated weight management program completion before bariatric surgery provides no long-term clinical benefit.

BACKGROUND: There is no evidence that insurance-mandated weight loss before bariatric surgery affects outcomes. OBJECTIVE: This retrospective study evaluated the relationship between insurance-mandated weight management program (WMP) completion before primary bariatric surgery and postoperative outcomes. SETTING: Suburban academic medical center. METHODS: Patients who underwent laparoscopic Roux-en-Y gastric bypass (LRYGB, n = 572) or sleeve gastrectomy (SG, n = 484) from 2014 to 2019 were dichotomized to presence (LRYGB n = 431, SG n = 348) or absence (LRYGB n = 141, SG n = 136) of insurance-mandated WMP completion. Primary endpoints included follow-up rate, percent total weight loss (%TWL), and percent excess weight loss (%EWL) through 60 months after surgery. The Mann-Whitney U test compared between-group means with significance at P < .05. RESULTS: Follow-up rate, %TWL, and %EWL were not different (P = NS) up to 60 months postoperation between groups for either surgery. Both LRYGB and SG patients without WMP completion maintained greater %TWL (LRYGB: 34.4 ± 11.1% versus 29.8 ± 11.0%, P = .159; SG: 21.4 ± 10.0% versus 18.2 ± 10.5%, P = .456) and %EWL (LRYGB: 71.3 ± 26.3% versus 67.6 ± 26.5%, P = .618; SG: 49.2 ± 18.8% versus 47.5 ± 28.8%, P = .753) at 36 months after surgery. Secondarily, duration of time to get to surgery was significantly greater among yes-WMP patients (LRYGB: 178 days versus 121 days, P < .001; SG: 169 days versus 95 days, P < .001). CONCLUSION: Insurance-mandated WMP completion before bariatric surgery delays patient access to surgery without improving postoperative weight loss potential and must be abandoned.