Citations

Abstract The link between bipolar disorder (BP) and immune dysfunction remains controversial. While epidemiological studies have long suggested an association, recent research has found only limited evidence of such a relationship. To clarify this, we investigated the contributions of immune-relevant genetic factors to the response to lithium (Li) treatment and the clinical presentation of BP. First, we assessed the association of a large collection of immune-related genes (4,925) with Li response, defined by the Retrospective Assessment of the Lithium Response Phenotype Scale (Alda scale), and clinical characteristics in patients with BP from the International Consortium on Lithium Genetics (ConLi+Gen, N = 2,374). Second, we calculated here previously published polygenic scores (PGSs) for immune-related traits and evaluated their associations with Li response and clinical features. We found several genes associated with Li response at p < 1x10− 4 values, including HAS3, CNTNAP5 and NFIB. Network and functional enrichment analyses uncovered an overrepresentation of pathways involved in cell adhesion and intercellular communication, which appear to converge on the well-known Li-induced inhibition of GSK-3β. We also found various genes associated with BP’s age-at-onset, number of mood episodes, and presence of psychosis, substance abuse and/or suicidal ideation at the exploratory threshold. These included RTN4, XKR4, NRXN1, NRG1/3 and GRK5. Additionally, PGS analyses suggested serum FAS, ECP, TRANCE and cytokine ligands, amongst others, might represent potential circulating biomarkers of Li response and clinical presentation. Taken together, our results support the notion of a relatively weak association between immunity and clinically relevant features of BP at the genetic level.

Introduction and Objective Alcohol consumption has increased dramatically in recent years, representing a significant challenge to human health in metabolic disease. The leading cause of alcohol‐related death is alcohol‐associated liver disease (AALD), which is present at early stages (i.e. steatosis) in 90% of heavy drinkers. During early AALD, liver hepatocytes accumulate large stores of triglycerides in the form of lipid droplets (LDs). Under normal conditions, degradative lysosomes form direct contacts with LDs and catabolize lipid via microlipophagy, a specialized autophagic pathway utilizing the lipid‐degrading enzyme lysosomal acid lipase (LAL). However, the trafficking mechanisms that govern LD‐lysosome contacts during microlipophagy are poorly understood. Several promising candidates exist within the Rab family of small GTPases, which are well‐known to direct the trafficking of intracellular vesicles and LDs. Moreover, previous studies suggest that Rab proteins play central roles in LD catabolism. Thus, the OBJECTIVE of this study was to investigate novel Rab proteins that might be impaired by EtOH leading to altered LD dynamics and microautophagy. Materials and Methods To this end, we utilized RNAi gene silencing, subcellular fractionation, Western blot analysis, and high‐resolution microscopy to define Rabs that might target LDs to lysosomes during microlipophagy. To mimic alcoholic fatty liver, cellular and animal models of alcohol consumption were also used. Changes in LD‐lysosome interaction were measured by quantitative confocal microscopy following pharmacological inhibition of LAL by LAListat. Results First, confocal microscopy revealed that GFP‐Rab5, an early endosomal Rab GTPase, localizes to hepatocellular LDs consistent with proteomic and Western blot analyses showing abundant levels of Rab5 in biochemically isolated LDs. Importantly, siRNA knockdown of Rab5 in cultured hepatocytes showed substantial increases in total LD area (2‐fold) and LD number (1.6‐fold), and also blocked the catabolism of LDs in lipid‐loaded cells. Finally, Rab5 knockdown nearly completely abolished microlipophagy as measured by fluorescent LD accumulation in lysosomes following LAListat treatment. The dissociation of LDs from lysosomes in Rab5 knockdown cells was strikingly similar to the defect observed in EtOH‐fed hepatocytes. Together, these findings suggest that Rab5 is a key mediator of targeting LDs to the lysosome compartment for catabolism and may be a target of EtOH insult. Significance/Implication This study sheds light on new molecular mechanisms of microlipophagy that are affected by chronic alcohol consumption. These mechanisms may represent promising avenues for future therapeutic development toward mitigating hepatic steatosis and slowing the progression of AALD.

AbstractInhaled treprostinil is an approved therapy for pulmonary arterial hypertension (PAH) and pulmonary hypertension associated with interstitial lung disease in the United States. Studies have confirmed the robust benefits and safety of nebulized inhaled treprostinil, but it requires a time investment for nebulizer preparation, maintenance, and treatment. A small, portable treprostinil dry powder inhaler has been developed for the treatment of PAH. The primary objective of this study was to evaluate the safety and tolerability of treprostinil inhalation powder (TreT) in patients currently treated with treprostinil inhalation solution. Fifty‐one patients on a stable dose of treprostinil inhalation solution enrolled and transitioned to TreT at a corresponding dose. Six‐minute walk distance (6MWD), device preference and satisfaction (Preference Questionnaire for Inhaled Treprostinil Devices [PQ‐ITD]), PAH Symptoms and Impact (PAH‐SYMPACT®) questionnaire, and systemic exposure and pharmacokinetics for up to 5 h were assessed at baseline for treprostinil inhalation solution and at Week 3 for TreT. Adverse events (AEs) were consistent with studies of inhaled treprostinil in patients with PAH, and there were no study drug‐related serious AEs. Statistically significant improvements occurred in 6MWD, PQ‐ITD, and PAH‐SYMPACT. Forty‐nine patients completed the 3‐week treatment phase and all elected to participate in an optional extension phase. These results demonstrate that, in patients with PAH, transition from treprostinil inhalation solution to TreT is safe, well‐tolerated, and accompanied by statistically significant improvements in key clinical assessments and patient‐reported outcomes with comparable systemic exposure between the two formulations at evaluated doses (trial registration: clinicaltrials.gov identifier: NCT03950739).

ABSTRACT Lipophagy is a central cellular process for providing the cell with a readily utilized, high energy source of neutral lipids. Since its discovery over a decade ago, we are just starting to understand the molecular components that drive lipophagy, how it is activated in response to nutrient availability, and its potential as a therapeutic target in disease. In this Cell Science at a Glance article and the accompanying poster, we first provide a brief overview of the different structural and enzymatic proteins that comprise the lipid droplet (LD) proteome and reside within the limiting phospholipid monolayer of this complex organelle. We then highlight key players in the catabolic breakdown of LDs during the functionally linked lipolysis and lipophagy processes. Finally, we discuss what is currently known about macro- and micro-lipophagy based on findings in yeast, mammalian and other model systems, and how impairment of these important functions can lead to disease states.

AbstractBackgroundSolid‐phase platelet crossmatch (PXM) testing is used to help manage patients with platelet transfusion‐refractoriness. Recently, we published the first report of false‐negative PXM results from prozone effect that was mitigated using sample dilution. This study aimed to describe the prevalence of PXM prozone effect and the levels of class I HLA antibodies (HLA‐Abs) associated with positive PXM results and with false‐negative PXM results from prozone effect.Study Design and MethodsA cross‐sectional study of patients undergoing PXM testing from July 2019 through December 2020 was performed. All PXM tests were run simultaneously using undiluted and 1:4 diluted patient plasma. Prozone effect was defined as a negative PXM result using undiluted patient plasma but a positive PXM result using 1:4 diluted patient plasma.ResultsAmong 59 patients, 830 individual ABO‐compatible PXM results yielded an overall positivity rate of 25.8% (214/830) and a false‐negative rate from prozone effect of 4.7% (10/214). Among the 28 patients with class I HLA‐Ab testing and no other anti‐platelet antibodies, maximum HLA‐Ab mean fluorescence intensity (MFI) was significantly associated with a positive PXM result (p < .0001; AUC approx. 0.9) and categorized into negative (<3700), indeterminate (3700–10300), and positive (>10300) maximum HLA‐Ab MFI zones. Maximum HLA‐Ab MFI, however, was not associated with prozone effect (p = .17; AUC approx. 0.6).DiscussionWhile there is a strong predictive association between class I HLA‐Ab levels and positive PXM results, PXM prozone effect is a common occurrence not associated with class I HLA‐Ab levels, so additional testing with diluted samples should be considered.

Background: Abnormal breathing, or “gasping,” frequently occurs during cardiac arrest and has been associated with increased survival. During 9-1-1 calls, early recognition of gasping may allow dispatchers to identify OHCA and to start CPR instructions promptly. Objective: To characterize lay rescuers’ descriptions of abnormal breathing during OHCA. Methods: 9-1-1 audio recordings of 4,279 confirmed OHCAs (10/10-7/14) in Arizona were reviewed by program personnel. Terms used by lay rescuers to describe victims’ breathing were recorded in a structured database. Results: Abnormal breathing (as opposed to “not breathing”) was described in 542/4279 (13%) calls. There were 623 verbal descriptions. A total of 50 different terms were used. However, the top 8 accounted for 83% and the remaining 42 descriptions (“Other”) comprised only 17% of all terms used. “Gasping” was the most commonly used term (30%; 187/623), followed by “snoring” (15%; 95/623; Figure). Conclusion: Lay rescuers used a wide variety of terms to describe abnormal breathing in documented OHCA. However, 8 terms accounted for 83% of descriptions. Familiarizing 9-1-1 telecommunicators with the most commonly used terms may improve the accuracy of recognition and hasten the identification of OHCA.

Background: Bystander CPR (BCPR) increases survival from OHCA yet is provided in a minority of cases. The AHA has promulgated guidelines on the provision of pre-arrival Telephone CPR (TCPR) instructions and measurement to increase the proportion of BCPR; however, the impact of those guidelines on survival is unknown. Objective: To describe the impact of a comprehensive bundle of 9-1-1 TCPR protocol, training, data collection, and feedback on BCPR and survival from OHCA across the state of Arizona. Methods: 9-1-1 audio recordings of confirmed OHCAs and suspected OHCAs (10/2010-6/2013) in 7 large 9-1-1 centers were reviewed using a standardized time-stamp methodology linked with EMS and hospital process and outcome data. There were 2343 pre-implementation cases (P1) and 2291 cases post-implementation of a bundle of care (P2) that included staff training and guideline-based protocol changes, data collection and feedback to providers. Univariate and multivariable analyses were used to assess outcomes between P1 and P2. Results: There were 2532 OHCAs [1232 P1, 1300 P2; 64% male, median age 62 (IQR: 47-74)]. 83% of cases were identified in P1 compared with 89% in P2 (p<0.001). The rate of telephone-assisted BCPR went from 44% in P1 to 62% in P2 (p<0.001). Time to beginning TCPR instructions decreased from a median of 144 sec (P1) to 126 in P2 (p<0.001). Time to first chest compression also decreased (P1: 178; P2: 155; p<0.001). Outcome data are currently available for 64% of confirmed OHCAs (1630 patient outcomes with 1619 neuro outcomes). Survival was significantly higher in P2 (11.2%) compared to P1 (7.9%; p=0.023), as was good neuro outcome (CPC-1 or 2: 7.7% P2 vs. 4.8% P1 p=0.018). After adjusting for witnessed arrest, shockable rhythms, age, and sex, both survival and good neuro outcome were still significantly higher in P2 vs. P1 [adjusted odds ratios: survival = 1.5 (95% 1.1-2.1); good neuro outcome = 1.7 (95% 1.1-2.6)]. Conclusion: The implementation of a comprehensive statewide TCPR bundle was associated with significant improvements in the rates of telephone-assisted BCPR, survival and good neurologic outcome after OHCA.

Background: Spontaneous spinal subarachnoid hemorrhage (SSAH) is a rare but serious condition that can lead to a variety of medical complications. Methods: Using the Mayo Clinic Rochester database, patients admitted to the Mayo Clinic Rochester, MN hospital with spontaneous SSAH (not iatrogenic or traumatic) between January 2000 and December 2015 were retrospectively reviewed. Demographic and clinical data and functional outcomes as described by the modified Rankin Scale (mRS) score at the time of discharge and at post-admission follow-up were assessed. Results: Eight consecutive patients (median age 70 years, range 51-87) were identified. Seven patients presented with acute onset back pain or headache. Seven patients had poorly controlled chronic hypertension. Two patients had vasculitis, and one had an arteriovenous malformation (AVM). An increase in blood pressure was observed in all patients during their acute presentation as compared to their baseline outpatient readings. Complications included cord compression (n = 4), hyponatremia (n = 5), sulcal subarachnoid hemorrhage (n = 2), chronic arachnoiditis (n=1), vasospasm (n=1), and late cord ischemia (n = 1). All eight patients were managed medically including blood pressure control and repeat imaging. One patient had an aneurysm which was embolized, and two received steroids for vasculitis. One patient died during hospitalization, one died within a week of discharge, five had improved mRS score at post-hospitalization follow-up and had unchanged mRS of 1 at discharge and follow-up. Conclusions: To our knowledge this is the first compilation of cases of spontaneous SSAH. Risk factors for spontaneous SSAH are hypertension, AVM, vasculitis, coarctation of the aorta, and malignancy. Symptomatic cord compression is not uncommon, but can be managed conservatively.

Neutral lipids are a critical source for cellular energy and are stored within specialized organelles known as lipid droplets (LD). Degradation of LDs for energy utilization is accomplished by two principal pathways: lipolysis that is activated by cAMP to recruit adipose triglyceride lipase (ATGL) to the LD surface, and lipophagy that utilizes the autophagic machinery to target and traffic LDs for degradation by lysosomal acid lipase (LAL). However, the mechanisms underlying synergy between these seemingly distinct pathways are not well understood. Previous studies show that autpohagic membrane cannot effectively engulf large organelles, but is size‐restricted to small cargo. Based on this, we HYPOTHESIZE that lipolysis and lipophagy are sequential pathways whereby lipolysis first reduces the size of large LDs to allow for subsequent autophagic engulfment of small LDs for lipophagy. Methods Using light and electron microscopy combined with biochemical approaches, we explored LD size and the sequential nature of lipolysis and lipophagy in primary rat and AML12 hepatocytes. Live‐cell microscopy was used for the first time to monitor LDs transitioning from lipolysis in the cytoplasm to lipophagy within endolysosomal vesicles. Results Confocal microscopy of endogenous ATGL revealed a preferential association with large LDs with an average size of 4.0 μm 2 , seven‐fold larger than LDs not associated with ATGL. In striking comparison, LDs associated with components of the autophagic machinery (LC3, Lamp3) were 50% smaller in size (0.39 μm 2 ). Consistent with this observation, siRNA knockdown of ATGL resulted in the persistence of large LDs (2.8 μm 2 ), whereas knockdown of LAL left cells filled with numerous small LDs (1.5 μm 2 ). These observations were mimicked by inhibitors of ATGL (atglistatin) and LAL (lalistat). In support of these findings, differential centrifugation of AML12 homogenates allowed for separation of two distinct populations of LDs: a buoyant fraction of large LDs enriched in the cytosolic lipase ATGL, and a second collection of smaller, less buoyant LDs enriched in lysosomal enzymes such as Lamp2A, the autophagosome marker LC3‐II, and the endosomal marker Tsg101. Most interesting are time lapse movies of live cells showing engulfment of small LDs by a Lamp3‐positive late endosomal compartment, suggesting that these organelles play an important role in the direct targeting and engulfment of LDs for lipophagy. Conclusion Hepatocytes appear to catabolize LDs in a tandem stepwise process that first utilizes cytosolic lipases to substantially reduce LD size, thereby allowing for subsequent engulfment of small LDs by autophagosomes as well as late endosomes and lysosomes. Support or Funding Information Supported by NIAAA RO1AA020735 to MAM; NIDDK award T32DK007352 to MBS and RJS, and the Mayo Clinic Kogod Aging Fellowship to MBS. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .

Fatty liver disease affects 80–100 million Americans and is a precursor to irreversible and sometimes fatal liver damage. The initial stages of fatty liver disease are marked by the hepatocellular accumulation of fat‐storage organelles known as lipid droplets (LDs) that are degraded by two pathways: lipolysis that involves the recruitment of cytosolic lipases (ATGL, HSL) to the LD surface, and lipophagy that relies on autophagic membranes to target and traffic LDs for lysosomal degradation. Importantly, the mechanisms underlying a cooperation between these seemingly distinct pathways are not well understood. Previous studies have shown that the autophagic engulfment of cytosolic cargo is size‐restricted. Because of this, we HYPOTHESIZE that lipolysis and lipophagy occur as sequential processes initiated by cytosolic lipases to reduce LD size and allow for subsequent engulfment by autophagic membranes. Methods In AML12 hepatocytes, immunofluorescence microscopy and biochemical approaches were used to determine the enrichment of lipolysis vs lipophagy machinery on large vs. small LDs. Live‐cell microscopy was used for the first time to monitor LDs transitioning from lipolysis to lipophagic engulfment. Results Confocal microscopy of AML12 cells immunolabeled for adipose triglyceride lipase (ATGL) revealed a preferential association with large LDs with an average area of 4.0 μm 2 , seven‐fold larger than LDs not associated with ATGL. In striking comparison, LDs associated with components of the autophagic machinery (LC3) were two‐fold smaller in area (0.39 μm 2 ). Consistent with this observation was the finding that siRNA knockdown of ATGL resulted in the persistence of large LDs (2.8 μm 2 ), whereas knockdown of lysosomal acid lipase (LAL) left cells filled with many LDs of a smaller size (1.5 μm 2 ). These observations were mimicked by inhibitors of ATGL (atglistatin) and lysosomal acidification (chloroquine). In support of these findings, differential centrifugation of AML12 homogenates allowed for separation of two distinct populations of LDs: a buoyant fraction of large LDs enriched in the cytosolic lipase ATGL, and a second collection of smaller, less buoyant LDs enriched in lysosomal enzymes such as Lamp2A and the autophagosome marker LC3‐II. Most interesting are time lapse movies of live cells showing engulfment of small LDs by a LAMP3‐positive late endosomal/lysosomal compartment, suggesting that these organelles play an important role in the direct targeting and engulfment of LDs for lipophagy. Conclusion Hepatocytes appear to catabolize LDs in a tandem stepwise process that first utilizes cytosolic lipases to substantially reduce LD size, thereby allowing for subsequent engulfment by autophagosomes as well as late endosomes and lysosomes. Support or Funding Information This study was generously supported by funding from NIAAA R01AA020735, NIDDK T32DK007352, and the Mayo Clinic Robert and Arlene Kogod Center on Aging. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .