Citations

Background:Previous reports suggest that lipid droplets (LDs) in the hepatocyte can be catabolized by a direct engulfment from nearby endolysosomes (microlipophagy). Further, it is likely that this process is compromised by chronic ethanol (EtOH) exposure leading to hepatic steatosis. This study investigates the hepatocellular machinery supporting microlipophagy and EtOH-induced alterations in this process with a focus on the small, endosome-associated, GTPase Rab5.Methods and Results:Here we report that this small Ras-related GTPase is a resident component of LDs, and its activity is important for hepatocellular LD-lysosome proximity and physical interactions. We find that Rab5 siRNA knockdown causes an accumulation of LDs in hepatocytes by inhibiting lysosome dependent LD catabolism. Importantly, Rab5 appears to support this process by mediating the recruitment of early endosomal and or multivesicular body compartments to the LD surface before lysosome fusion. Interestingly, while wild-type or a constituently active GTPase form (Q79L) of Rab5 supports LD-lysosome transport, this process is markedly reduced in cells expressing a GTPase dead (S34N) Rab5 protein or in hepatocytes exposed to chronic EtOH.Conclusions:These findings support the novel premise of an early endosomal/multivesicular body intermediate compartment on the LD surface that provides a “docking” site for lysosomal trafficking, not unlike the process that occurs during the hepatocellular degradation of endocytosed ligands that is also known to be compromised by EtOH exposure.

DNA replication is a vulnerable cellular process, and its deregulation leads to genomic instability. Here, we demonstrate that chromobox protein homolog 3 (CBX3) binds replication protein A 32-kDa subunit (RPA2) and regulates RPA2 retention at stalled replication forks. CBX3 is recruited to stalled replication forks by RPA2 and inhibits ring finger and WD repeat domain 3 (RFWD3)–facilitated replication restart. Phosphorylation of CBX3 at serine-95 by casein kinase 2 (CK2) kinase augments cadherin 1 (CDH1)–mediated CBX3 degradation and RPA2 dynamics at stalled replication forks, which permits replication fork restart. Increased expression of CBX3 due to gene amplification or CK2 inhibitor treatment sensitizes prostate cancer cells to poly(ADP-ribose) polymerase (PARP) inhibitors while inducing replication stress and DNA damage. Our work reveals CBX3 as a key regulator of RPA2 function and DNA replication, suggesting that CBX3 could serve as an indicator for targeted therapy of cancer using PARP inhibitors.

OBJECTIVE The COVID-19 pandemic led to many changes across medical organizations and graduate medical education programs nationwide including the rapid implementation of telemedicine as a modality for delivering health care. The purpose of this study was to investigate the telemedicine experiences of residents and fellows with their self-reported level of preparedness, impact on their education including precepting, skill development, and patient-physician relationships, and perceptions of telehealth platforms and curricula in the future. METHODS A total of 365 Mayo Clinic residents and fellows across three sites (Florida, Arizona, and Minnesota) were identified as trainees who conducted at least one telemedicine encounter from January 1, 2020 to June 30, 2020 and were sent an electronic survey by e-mail. RESULTS There was a total of 103 completed surveys across various specialties with 58.3% female respondents, 63.1% residents, 35.0% fellows and 77.7% of respondents who attended medical school in the United States. Most trainees reported having very little to no exposure to telemedicine in their medical careers before the pandemic. The majority were satisfied with their first telemedicine encounter and found precepting comparable to in-person visits. The trainees in this study had a favorable view with 98.1% believing telemedicine will play a more prevalent role in the future and most agreed this should be included in medical school and residency training. CONCLUSION Our survey found that after the implementation of telemedicine during the COVID-19 pandemic, the experiences of trainees at a multi-site academic center were overall positive. More research is needed on the perceptions of skill development (physical exam and history taking) during a telemedicine encounter and outlining an optimal telemedicine curriculum that can improve confidence in trainees.

Abstract Background The US Centers for Disease Control and Prevention recommends HIV testing every 3 months in oral PrEP users. We performed a national assessment of HIV testing compliance among oral PrEP users. Methods We analyzed 408 910 PrEP prescriptions issued to 39 809 PrEP users using a national insurance claims database that contained commercial and Medicaid claims. We identified PrEP use based on pharmacy claims and outpatient diagnostic coding. We evaluated the percentage of PrEP prescription refills without HIV testing (identified by CPT codes) within the prior 3, 6, and 12 months using time to event methods. We performed subgroup and multivariate analyses by age, gender, race, insurance type, and geography. Results Of 39 809 persons, 36 197 were commercially insured, 3612 were Medicaid-insured, and 96% identified as male; the median age (interquartile range) was 34 (29–44) years, and the Medicaid-insured PrEP users were 24% Black/African American, 44% White, and 9% Hispanic/Latinx. Within the prior 3, 6, and 12 months, respectively, the percentage of PrEP prescription fills in individuals without HIV Ag/Ab testing was 34.3% (95% CI, 34.2%–34.5%), 23.8% (95% CI, 23.7%–23.9%), and 16.6% (95% CI, 16.4%–16.7%), and the percentage without any type of HIV test was 25.8% (95% CI, 25.6%–25.9%), 14.6% (95% CI, 14.5%–14.7%), and 7.8% (95% CI, 7.7%–7.9%). Conclusions Approximately 1 in 3 oral PrEP prescriptions were filled in persons who had not received an HIV Ag/Ab test within the prior 3 months, with evidence of health disparities. These findings inform clinical PrEP monitoring efforts and compliance with national HIV testing guidance to monitor PrEP users.

Abstract Endocrine therapies (ET) with cyclin-dependent kinase 4/6 (CDK4/6) inhibition are the standard treatment for estrogen receptor-α-positive (ER+) breast cancer, however drug resistance is common. In this study, proteogenomic analyses of patient-derived xenografts (PDXs) from patients with 22 ER+ breast cancer demonstrated that protein kinase, membrane-associated tyrosine/threonine one (PKMYT1), a WEE1 homolog, is estradiol (E2) regulated in E2-dependent PDXs and constitutively expressed when growth is E2-independent. In clinical samples, high PKMYT1 mRNA levels associated with resistance to both ET and CDK4/6 inhibition. The PKMYT1 inhibitor lunresertib (RP-6306) with gemcitabine selectively and synergistically reduced the viability of ET and palbociclib-resistant ER+ breast cancer cells without functional p53. In vitro the combination increased DNA damage and apoptosis. In palbociclib-resistant, TP53 mutant PDX-derived organoids and PDXs, RP-6306 with low-dose gemcitabine induced greater tumor volume reduction compared to treatment with either single agent. Our study demonstrates the clinical potential of RP-6306 in combination with gemcitabine for ET and CDK4/6 inhibitor resistant TP53 mutant ER+ breast cancer.

Acute pancreatitis (AP) is among the most common hospital gastrointestinal diagnoses; understanding the mechanisms underlying the severity of AP is critical for development of new treatment options for this disease. Here, we evaluate the biological function of phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) in AP pathogenesis in 2 independent genetically engineered mouse models of AP. PFKFB3 was elevated in AP and severe AP (SAP), and KO of Pfkfb3 abrogated the severity of alcoholic SAP (FAEE-SAP). Using a combination of genetic, pharmacological, and molecular studies, we defined the interaction of PFKFB3 with inositol 1,4,5-trisphosphate receptor (IP3R) as a key event mediating this phenomenon. Further analysis demonstrated that the interaction between PFKFB3 and IP3R promotes FAEE-SAP severity by altering intracellular calcium homeostasis in acinar cells. Together, our results support a PFKFB3-driven mechanism controlling AP pathobiology and define this enzyme as a therapeutic target to ameliorate the severity of this condition.

AbstractMyhre syndrome is an increasingly diagnosed ultrarare condition caused by recurrent germline autosomal dominant de novo variants in SMAD4. Detailed multispecialty evaluations performed at the Massachusetts General Hospital (MGH) Myhre Syndrome Clinic (2016–2023) and by collaborating specialists have facilitated deep phenotyping, genotyping and natural history analysis. Of 47 patients (four previously reported), most (81%) patients returned to MGH at least once. For patients followed for at least 5 years, symptom progression was observed in all. 55% were female and 9% were older than 18 years at diagnosis. Pathogenic variants in SMAD4 involved protein residues p.Ile500Val (49%), p.Ile500Thr (11%), p.Ile500Leu (2%), and p.Arg496Cys (38%). Individuals with the SMAD4 variant p.Arg496Cys were less likely to have hearing loss, growth restriction, and aortic hypoplasia than the other variant groups. Those with the p.Ile500Thr variant had moderate/severe aortic hypoplasia in three patients (60%), however, the small number (n = 5) prevented statistical comparison with the other variants. Two deaths reported in this cohort involved complex cardiovascular disease and airway stenosis, respectively. We provide a foundation for ongoing natural history studies and emphasize the need for evidence‐based guidelines in anticipation of disease‐specific therapies.

LINKED CONTENTThis article is linked to Yiu et al papers. To view these articles, visit https://doi.org/10.1111/apt.18006 and https://doi.org/10.1111/apt.18057

Abstract Background Chronic migraine exerts substantial negative impacts on daily functioning. Efforts to manage impaired functioning may result in medication overuse, which contributes to the worsening profile and chronification of migraine. The Migraine Functional Impact Questionnaire (MFIQ) is a recently developed measure assessing the impact of migraine on physical, social, and emotional function. Objective The objective of this analysis was to assess changes in MFIQ scores following initiation or modification of migraine preventive medication and determine if changes in function are associated with changes in other aspects of migraine burden, such as headache frequency, headache intensity, and symptoms of anxiety and depression. Methods This is a secondary analysis of data from the Medication Overuse Treatment Strategy (MOTS) trial, a prospective pragmatic clinical trial that investigated two treatment strategies for those with chronic migraine and medication overuse. Data from both treatment arms were pooled and analyzed using a pre–post design. Prior to and 12 weeks following initiation or modification of migraine preventive medication, participants completed a series of questionnaires that captured migraine characteristics, medication use, migraine‐related physical impairment (MFIQ), anxiety (Generalized Anxiety Disorder‐7), and depression (Patient Health Questionnaire 9 [PHQ‐9]) symptoms. Changes from baseline in all measures were assessed using the paired t ‐test. Relationships between changes in MFIQ scores and other measures were assessed using linear regression. Multivariable modeling was performed to determine which additional variables contributed to the change in MFIQ beyond that already explained by an individual variable. Model terms were selected by using elastic net regularization. Only those participants who completed the baseline and 12‐week MFIQ were included in this analysis. Results Of the 537 patients, 88.2% were female, and the average age was 45 years (standard deviation 13). The mean frequency of days with moderate‐to‐severe headache improved 39.2% from 13.5 per 30 days at baseline to 8.1 per 30 days at week 12. The mean MFIQ Usual Activities Global score improved by 15.0 points (on a 100‐point scale). All five domains (Usual Activities Global, Usual Activities, Social Function, Emotional Function, Physical Function) of the MFIQ improved by a mean of at least 13.0 points. Changes in PHQ‐9 score, followed by changes in headache frequency, had the strongest associations with change in all domains of the MFIQ. Conclusions The negative impact of chronic migraine with medication overuse on physical, social, and emotional functioning substantially lessened following initiation or modification of migraine preventive medication. Improved functioning, as measured by the MFIQ, was most strongly associated with reductions in depression scores and headache frequency, highlighting the importance of recognizing and monitoring changes in depressive symptoms, in addition to headache frequency and functional impairment, when evaluating response to preventive medications.