Impaired AMPK Control of Alveolar Epithelial Cell Metabolism Promotes Pulmonary Fibrosis

Alveolar epithelial type II (AT2) cell dysfunction is implicated in the pathogenesis of familial and sporadic idiopathic pulmonary fibrosis (IPF). We previously described that expression of an AT2 cell exclusive disease-associated protein isoform (SP-CI73T) in murine and patient-specific induced pluripotent stem cell (iPSC)-derived AT2 cells leads to a block in late macroautophagy and promotes time-dependent mitochondrial impairments; however, how a metabolically dysfunctional AT2 cell results in fibrosis remains elusive. Here using murine and human iPSC-derived AT2 cell models expressing SP-CI73T, we characterize the molecular mechanisms governing alterations in AT2 cell metabolism that lead to increased glycolysis, decreased mitochondrial biogenesis, disrupted fatty acid oxidation, accumulation of impaired mitochondria, and diminished AT2 cell progenitor capacity manifesting as reduced AT2 self-renewal and accumulation of transitional epithelial cells. We identify deficient AMP-kinase signaling as a key upstream signaling hub driving disease in these dysfunctional AT2 cells and augment this pathway to restore alveolar epithelial metabolic function, thus successfully alleviating lung fibrosis in vivo.

PGF2α signaling drives fibrotic remodeling and fibroblast population dynamics in mice

Idiopathic pulmonary fibrosis (IPF) is a chronic parenchymal lung disease characterized by repetitive alveolar cell injury, myofibroblast proliferation, and excessive extracellular matrix deposition for which unmet need persists for effective therapeutics. The bioactive eicosanoid, prostaglandin F2α, and its cognate receptor FPr (Ptgfr) are implicated as a TGF-β1-independent signaling hub for IPF. To assess this, we leveraged our published murine PF model (IER-SftpcI73T) expressing a disease-associated missense mutation in the surfactant protein C (Sftpc) gene. Tamoxifen-treated IER-SftpcI73T mice developed an early multiphasic alveolitis and transition to spontaneous fibrotic remodeling by 28 days. IER-SftpcI73T mice crossed to a Ptgfr-null (FPr-/-) line showed attenuated weight loss and gene dosage-dependent rescue of mortality compared with FPr+/+ cohorts. IER-SftpcI73T/FPr-/- mice also showed reductions in multiple fibrotic endpoints for which administration of nintedanib was not additive. Single-cell RNA-Seq, pseudotime analysis, and in vitro assays demonstrated Ptgfr expression predominantly within adventitial fibroblasts, which were reprogrammed to an "inflammatory/transitional" cell state in a PGF2α /FPr-dependent manner. Collectively, the findings provide evidence for a role for PGF2α signaling in IPF, mechanistically identify a susceptible fibroblast subpopulation, and establish a benchmark effect size for disruption of this pathway in mitigating fibrotic lung remodeling.

Disruption of Prostaglandin F2α Receptor Signaling Attenuates Fibrotic Remodeling and Alters Fibroblast Population Dynamics in A Preclinical Murine Model of Idiopathic Pulmonary Fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a chronic parenchymal lung disease characterized by repetitive alveolar cell injury, myofibroblast proliferation, and excessive extracellular matrix deposition for which unmet need persists for effective therapeutics. The bioactive eicosanoid, prostaglandin F2α, and its cognate receptor FPr (Ptfgr) are implicated as a TGFβ1 independent signaling hub for IPF. To assess this, we leveraged our published murine PF model (IER - SftpcI73T) expressing a disease-associated missense mutation in the surfactant protein C (Sftpc) gene. Tamoxifen treated IER-SftpcI73T mice develop an early multiphasic alveolitis and transition to spontaneous fibrotic remodeling by 28 days. IER-SftpcI73T mice crossed to a Ptgfr null (FPr-/-) line showed attenuated weight loss and gene dosage dependent rescue of mortality compared to FPr+/+ cohorts. IER-SftpcI73T/FPr-/- mice also showed reductions in multiple fibrotic endpoints for which administration of nintedanib was not additive. Single cell RNA sequencing, pseudotime analysis, and in vitro assays demonstrated Ptgfr expression predominantly within adventitial fibroblasts which were reprogrammed to an "inflammatory/transitional" cell state in a PGF2α/FPr dependent manner. Collectively, the findings provide evidence for a role for PGF2α signaling in IPF, mechanistically identify a susceptible fibroblast subpopulation, and establish a benchmark effect size for disruption of this pathway in mitigating fibrotic lung remodeling.

Development of a probability discounting task of communication for adults who stutter

Previous research indicates speaking may be emotionally and socially risky for adults who stutter (AWS) due to psychological distress induced by others following a dysfluency. This may impact communication-related decision-making; however, no measure had been developed to objectively quantify this variable. The present study aimed to develop and validate the Probability Discounting for Communication (PDC) task, a behavioral measure of risk taking that characterizes decreasing subjective value of hypothetical communication engagement as the probability of stuttering and listener reaction change. AWS (n = 67) and adults who do not stutter (AWNS; n = 93) were recruited from an online listserv and MTurk. Across a series of trials, participants completed the PDC by using a visual analog scale to indicate their subjective value of communication as probabilities of stuttering (1%-99%) and magnitudes of negative listener reaction risk (10%, 50%, 90%) were manipulated. They also completed measures of stuttering, communication, and demographics. Results revealed communication was discounted hyperbolically across increasing dysfluency odds. AWS showed more systematic discounting patterns compared to AWNS suggesting AWS may be more sensitive to communication due to experiences with stuttering. A magnitude effect was found with both AWS and AWNS discounting communication more steeply with increasing negative listener reaction risk. Significant associations were observed between discounting, stuttering, and communication measures among AWS, which indicates that sensitivity to risk in the context of stuttering and social reaction may influence communication engagement. Overall, the PDC functions as a measure to assess underlying decision-making patterns related to communication among AWS, which may inform treatment. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Patient-specific iPSCs carrying an SFTPC mutation reveal the intrinsic alveolar epithelial dysfunction at the inception of interstitial lung disease

Alveolar epithelial type 2 cell (AEC2) dysfunction is implicated in the pathogenesis of adult and pediatric interstitial lung disease (ILD), including idiopathic pulmonary fibrosis (IPF); however, identification of disease-initiating mechanisms has been impeded by inability to access primary AEC2s early on. Here, we present a human in vitro model permitting investigation of epithelial-intrinsic events culminating in AEC2 dysfunction, using patient-specific induced pluripotent stem cells (iPSCs) carrying an AEC2-exclusive disease-associated variant (SFTPCI73T). Comparing syngeneic mutant versus gene-corrected iPSCs after differentiation into AEC2s (iAEC2s), we find that mutant iAEC2s accumulate large amounts of misprocessed and mistrafficked pro-SFTPC protein, similar to in vivo changes, resulting in diminished AEC2 progenitor capacity, perturbed proteostasis, altered bioenergetic programs, time-dependent metabolic reprogramming, and nuclear factor κB (NF-κB) pathway activation. Treatment of SFTPCI73T-expressing iAEC2s with hydroxychloroquine, a medication used in pediatric ILD, aggravates the observed perturbations. Thus, iAEC2s provide a patient-specific preclinical platform for modeling the epithelial-intrinsic dysfunction at ILD inception.

The common ABCA3E292V variant disrupts AT2 cell quality control and increases susceptibility to lung injury and aberrant remodeling

ATP-binding cassette class A3 (ABCA3) is a lipid transporter that plays a critical role in pulmonary surfactant function. The substitution of valine for glutamic acid at codon 292 (E292V) produces a hypomorphic variant that accounts for a significant portion of ABCA3 mutations associated with lung disorders spanning from neonatal respiratory distress syndrome and childhood interstitial lung disease to diffuse parenchymal lung disease (DPLD) in adults including pulmonary fibrosis. The mechanisms by which this and similar ABCA3 mutations disrupt alveolar type 2 (AT2) cell homeostasis and cause DPLD are largely unclear. The present study, informed by a patient homozygous for the E292V variant, used an in vitro and a preclinical murine model to evaluate the mechanisms by which E292V expression promotes aberrant lung injury and parenchymal remodeling. Cell lines stably expressing enhanced green fluorescent protein (EGFP)-tagged ABCA3 isoforms show a functional deficiency of the ABCA3^E292V variant as a lipid transporter. AT2 cells isolated from mice constitutively homozygous for ABCA3^E292V demonstrate the presence of small electron-dense lamellar bodies, time-dependent alterations in macroautophagy, and induction of apoptosis. These changes in AT2 cell homeostasis are accompanied by a spontaneous lung phenotype consisting of both age-dependent inflammation and fibrillary collagen deposition in alveolar septa. Older ABCA3^E292V mice exhibit increased vulnerability to exogenous lung injury by bleomycin. Collectively, these findings support the hypothesis that the ABCA3^E292V variant is a susceptibility factor for lung injury through effects on surfactant deficiency and impaired AT2 cell autophagy.

Delay discounting and obesity in food insecure and food secure women

OBJECTIVES

The relation between food insecurity (FI) and delay discounting (DD) and probability discounting (PD) for food and money was tested in women. In addition, discounting was tested as a variable that mediates the relation between obesity and FI.

METHOD

Women recruited from a community sample (N = 92) completed questionnaires. They completed the food choice questionnaire, the monetary choice questionnaire, measures for food and money probability discounting (which quantify sensitivity to risk aversion), and demographic measures.

RESULTS

Women with FI had higher rates of obesity and higher food DD compared to food-secure women. However, DD for money or probability discounting for food or money did not significantly differ between FI and food secure groups when controlling for significant covariates. Neither DD or PD significantly mediated the relation between FI and obesity.

CONCLUSIONS

These results suggest that FI is associated with greater impulsive food choice, but its association with other monetary discounting and probability discounting for food and money appears contingent upon other demographic factors. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Middle fossa meningiomas

The middle cranial fossa is bounded anteriorly by the sphenoid ridge, medially by the lateral wall of the cavernous sinus and Meckel's cave, posteriorly by the sphenoid wing and petrous bone, and laterally by the greater wing of sphenoid and squamous temporal bone. In normal individuals, unnamed venous channels within the dura and arachnoid granulations can be seen on the floor of this fossa by the operating surgeon. Meningiomas arising mainly from the dura of the floor are uncommon, and middle fossa meningiomas have been arbitrarily named so based on an attachment of more than 75% to this location. They tend to present clinically at a large size and require special considerations for surgical treatment.

Global Gene Expression Analysis in an in vitro Fibroblast Model of Idiopathic Pulmonary Fibrosis Reveals Potential Role for CXCL14/CXCR4

Idiopathic Pulmonary Fibrosis (IPF) is a progressive disorder that is marked by an over accumulation of activated fibroblast populations. Despite the improved understanding of many mechanisms within this disease, global gene expression analysis has few focused studies on the fibroblast, the central effector cell of progressive fibrosis. We present a unique analysis of IPF pulmonary fibroblasts as they transition through cell culture and identify in vitro altered cellular processes. Fibroblasts were isolated from diseased (n = 8) and non-diseased (n = 4) lungs. Global gene expression analysis was carried out at the initial point of isolation and after 3 weeks of culture. We identify several genes that are altered by removal of the fibroblast from the IPF environment. Comparison of this subset of genes to four previously published whole lung analyses refined our list to a small subset of key fibroblast specific genes important in IPF. Application of STRING database analysis and confirmation via in-vitro and histological assay highlights the CXCL14/CXCR4 chemokine axis with a possible role in the progression and/or activation of fibroblasts within the IPF lung. Our findings, present a possible therapeutic target for IPF and a model for the study and discovery of novel protein and processes in this terrible disease.

The utility of behavioral economics in expanding the free-feed model of obesity

Animal models of obesity are numerous and diverse in terms of identifying specific neural and peripheral mechanisms related to obesity; however, they are limited when it comes to behavior. The standard behavioral measure of food intake in most animal models occurs in a free-feeding environment. While easy and cost-effective for the researcher, the free-feeding environment omits some of the most important features of obesity-related food consumption-namely, properties of food availability, such as effort and delay to obtaining food. Behavior economics expands behavioral measures of obesity animal models by identifying such behavioral mechanisms. First, economic demand analysis allows researchers to understand the role of effort in food procurement, and how physiological and neural mechanisms are related. Second, studies on delay discounting contribute to a growing literature that shows that sensitivity to delayed food- and food-related outcomes is likely a fundamental process of obesity. Together, these data expand the animal model in a manner that better characterizes how environmental factors influence food consumption.

Bovine leukaemia-virus infection in Costa Rica

The geographical distribution of bovine leukaemia-virus (BLV)-infected herds in Costa Rica and the isolation of BLV from cases of enzootic bovine leukosis are presented. It was found that BLV is prevalent throughout the country, affecting mostly dairy cattle (Bos taurus) located in the highlands around the central valley of Costa Rica. By contrast, beef cattle (Bos indicus) raised in the lowlands were affected to a lesser extent. One out of four isolates of BLV obtained from local cattle with lymphosarcomatous tumours was analysed and had similar physical, serological and biological characteristics to a reference strain of BLV isolated in the USA. However, different patterns of recognition of BLV-protein p24 were observed among naturally infected cattle using the western-blotting technique.

A study of pediatric house staff's knowledge of pulse oximetry

OBJECTIVE

Pulse oximetry is widely used to measure oxygen saturation in inpatient and outpatient settings. As with any medical technology, competence in interpretation and application of the data is essential for patient care. We therefore undertook a study to quantify pediatric house staff's knowledge of pulse oximetry and their ability to interpret the information.

METHODS

A 16-item multiple choice questionnaire (6 demographic, 10 knowledge) was developed to assess knowledge of pulse oximetry. The questionnaire was administered to a total of 134 pediatric house staff from five medical school-affiliated residency programs in New York City.

RESULTS

The mean test score and standard deviation was 64.3% +/- 1.9, with a range of 10% to 100%. Regarding three questions related to the knowledge of the oxyhemoglobin deviation curve, only 17% of the the respondents answered all three questions correctly. In three questions pertaining to the accuracy of the pulse oximeter, 36% of the respondents answered all questions correctly. Forty-three percent of the house staff believed that training in the use of pulse oximetry was inadequate.

CONCLUSIONS

The results showed that there is marked variability in pediatric house staff's knowledge of all aspects of pulse oximetry. This could contribute to patient morbidity. We suggest that medical schools and residency programs place more emphasis on teaching the principles and applications of pulse oximetry and the oxyhemoglobin dissociation curve.