Biology subjects

Shankar, K.

Publications and source records attributed to Shankar, K..

17 recordsLinked to original sources

bioRxiv2026

Tracing PFAS Transfer from Mother to the Fetoplacental Unit: Insights from Trimester-Specific Maternal Serum Profiles

Per- and polyfluoroalkyl substances (PFAS) are ubiquitous endocrine-disrupting pollutants that cross the placenta and affect offspring health, but the extent and timing of their transfer to placental and fetal compartments remain poorly understood. We characterized the relationship between trimester-specific prenatal maternal serum PFAS levels and paired placental and cord plasma levels at term. Data came from the Central Arkansas Glowing prospective cohort (n=151, 2010-2014). Four well-detected PFAS were measured using liquid chromatography-tandem mass spectrometry. Regression, elastic net, and parametric g-formula models tested the association between maternal levels in each trimester and placental or cord PFAS levels. In g-formula models, trimester one (T1) or trimester two (T2) measures consistently had the largest effect sizes associated with placental levels (p<0.001-0.05). Similarly, T1 (PFHxS, PFNA, PFOS, PFOA), T2 (PFNA, PFOS, PFOA), and placental PFOA were associated with cord plasma levels (p<0.05-p<0.001). Results were robust to time-varying adjustment for estimated glomerular filtration rate, serum albumin, or maternal weight. Predictive models improved with additional timepoint measures. Our findings suggest PFOA may transfer more efficiently from the placenta to cord plasma and early-to-mid gestation maternal serum PFAS measures may serve as the most robust sentinels of fetoplacental exposure burden, suggesting early exposure prevention should be prioritized.

pharmacology and toxicology↗

bioRxiv2025

Genome-wide association study of cocaine self-administration behavior in Heterogeneous Stock rats

BackgroundCocaine use disorder (CUD) is a major public health crisis with detrimental individual and societal effects. The specific genes mediating CUD remain largely unknown. MethodsWe conducted a genome-wide association study (GWAS) using outbred N/NIH Heterogeneous Stock (HS; n = 836, female = 415, male = 421) rats. We examined multiple CUD-related phenotypes that captured acquisition of self-administration, escalation of intake, and compulsive-like responding. ResultsConsistent with the existing literature, these traits were phenotypically and genetically correlated and exhibited modest heritability (h2 = 0.07 - 0.16). We identified six genome-wide significant associations. One locus on chromosome 19 was associated with the variable time between cocaine infusions (post infusion interval) and contains several carboxylesterase genes that are orthologous to the human CES1 gene; notably, carboxylesterases metabolize cocaine. Three non-synonymous coding variants in the genes Ces1c and Ces1d were in perfect linkage disequilibrium with this locus, suggesting that one or more of them might be the causal SNP. The other 5 loci also contained promising coding and expression variants, including Trak2, a gene previously associated with CUD in human GWAS and Slc10a7, Plcl1, and Satb2 which have been associated with alcohol and tobacco use disorder. ConclusionsThis is the largest genetic study of cocaine self-administration ever conducted in any species. Our results replicate previous loci associated with CUD in humans and provide several novel biological insights including the potential of pharmacological strategies targeting carboxylesterases for the treatment of CUD.

genetics↗

bioRxiv2025

Analysis of Divergent Gene Expression between HPV+ and HPV- Head and Neck Squamous Cell Carcinoma Patients

Human Papillomavirus (HPV) is a non-enveloped virus with a circular double-stranded DNA genome. It is one of the most common sexually transmitted infections, with high-risk types such as HPV-16 and HPV-18 linked to anogenital and head and neck squamous cell carcinomas (HNSCC). HNSCC includes cancers of the oral cavity, pharynx, larynx, and related regions, caused by carcinogens or persistent viral infections. HPV-positive (HPV+) HNSCC cases are more prevalent in Western countries and exhibit better prognosis and treatment response compared to HPV-negative (HPV-) cases. These differences suggest distinct fundamental differences between each subtype. This study analyzed RNA-seq data from the PanCancer Atlas 2018 dataset to investigate molecular distinctions between HPV+ and HPV-HNSCC. Using dimensionality reduction techniques such as Principal Component Analysis (PCA) and Uniform Manifold Approximation and Projection (UMAP), a clear clustering of HPV+ cases was observed, suggesting a unique gene expression profile. HPV+ tumors exhibited upregulation of genes involved in nucleic acid processing and downregulation of genes associated with apoptosis and epidermis development. These findings underscore the biological differences between HPV+ and HPV-HNSCC, offering insights into HPV-driven oncogenesis. Understanding these distinctions may improve patient stratification and inform targeted therapeutic strategies for HNSCC.

cancer biology↗

bioRxiv2024

Virus-free CRISPR knock-in of a chimeric antigen receptor into KLRC1 generates potent GD2-specific natural killer cells

Natural killer (NK) cells are an appealing off-the-shelf, allogeneic cellular therapy due to their cytotoxic profile. However, their activity against solid tumors remains suboptimal in part due to the upregulation of NK-inhibitory ligands, such as HLA-E, within the tumor microenvironment. Here, we utilize CRISPR-Cas9 to disrupt the KLRC1 gene (encoding the HLA-E-binding NKG2A receptor) and perform non-viral insertion of a GD2-targeting chimeric antigen receptor (CAR) within NK cells isolated from human peripheral blood. Genome editing with CRISPR/Cas9 ribonucleoprotein complexes yields efficient genomic disruption of the KLRC1 gene with 98% knockout efficiency and specific knock-in of the GD2 CAR transgene as high as 23%, with minimal off-target activity as shown by CHANGE-Seq, in-out PCR, and next generation sequencing. KLRC1-GD2 CAR NK cells display high viability and proliferation, as well as precise cellular targeting and potency against GD2+ human melanoma cells. Notably, KLRC1-GD2 CAR NK cells overcome HLA-E-based inhibition by HLA-E-expressing, GD2+ melanoma cells. Using a single-step, virus-free genome editing workflow, this study demonstrates the feasibility of precisely disrupting inhibitory signaling within NK cells via CRISPR/Cas9 while expressing a CAR to generate potent allogeneic cell therapies against HLA-E+ solid tumors.

bioengineering↗

bioRxiv2023

Giardia intestinalis deoxyadenosine kinase has a unique tetrameric structure that enables high substrate affinity and makes the parasite sensitive to deoxyadenosine analogues

Giardia intestinalis is a protozoan parasite causing giardiasis, a severe, sometimes even life-threatening, diarrheal disease. Giardia is one of only a few known organisms that lack de novo synthesis of DNA building blocks, and the parasite is therefore completely dependent on salvaging deoxyribonucleosides from the host. The deoxyribonucleoside kinases (dNKs) needed for this salvage are generally divided into two structurally distinct families, thymidine kinase 1 (TK1)-like dNKs and non-TK1-like dNKs. We have characterized the G. intestinalis deoxyadenosine kinase and found that it, in contrast to previously studied non-TK1-like dNKs, has a tetrameric structure. Deoxyadenosine was the best natural substrate of the enzyme (KM=1.12 M; Vmax=10.3 mol{middle dot}min-1{middle dot}mg-1), whereas the affinities for deoxyguanosine, deoxyinosine and deoxycytidine were 400-2000 times lower. Deoxyadenosine analogues halogenated at the 2- and/or 2 s-positions were also potent substrates, with comparable EC50 values as the main drug used today, metronidazole, but with the advantage of being usable on metronidazole-resistant parasites. Cryo-EM and 2.1 [A] X-ray structures of the enzyme in complex with the product dAMP (and dADP) showed that the tetramer is kept together by extended N- and C-termini that reach across from one canonical dimer to the next in a novel dimer-dimer interaction. Removal of the two termini resulted in lost ability to form tetramers and a 100-fold decreased deoxyribonucleoside substrate affinity. This is the first example of a non-TK1-like dNK that has a higher substrate affinity as the result of a higher oligomeric state. The development of high substrate affinity could be an evolutionary key factor behind the ability of the parasite to survive solely on deoxyribonucleoside salvage. Authors summaryThe human pathogen Giardia intestinalis is one of only a few organisms that lack ribonucleotide reductase and is therefore completely dependent on salvaging deoxyribonucleosides from the host for the supply of DNA building blocks. We have characterized one of the G. intestinalis salvage enzymes, which was named deoxyadenosine kinase based on its substrate specificity. The enzyme also phosphorylated many deoxyadenosine analogues that were equally efficient in preventing parasite growth as the most used drug today, metronidazole, and also usable against metronidazole-resistant parasites. Structural analysis of the enzyme with cryo-EM and X-ray crystallography showed that the enzyme was unique in its family of deoxyribonucleoside kinases by forming a tetramer and mutational analysis showed that tetramerization is a prerequisite for the high substrate affinity of the enzyme. The ability to gain substrate affinity by increasing the number of enzyme subunits could potentially represent an evolutionary pathway that has assisted the parasite to become able to survive entirely on salvage synthesis of DNA building blocks.

biochemistry↗

bioRxiv2023

VCD-induced menopause mouse model reveals reprogramming of hepatic metabolism

Menopause adversely impacts systemic energy metabolism and increases the risk of metabolic disease(s) including hepatic steatosis, but the mechanisms are largely unknown. Dosing female mice with vinyl cyclohexene dioxide (VCD) selectively causes follicular atresia in ovaries, leading to a murine menopause-like phenotype. In this study, we treated female C57BL6/J mice with VCD (160mg/kg i.p. for 20 consecutive days followed by verification of the lack of estrous cycling) to investigate changes in body composition, energy expenditure (EE), hepatic mitochondrial function, and hepatic steatosis across different dietary conditions. VCD treatment induced ovarian follicular loss and increased follicle-stimulating hormone (FSH) levels in female mice, mimicking a menopause-like phenotype. VCD treatment did not affect body composition, or EE in mice on a low-fat diet or in response to a short-term (1-week) high-fat, high sucrose diet (HFHS). However, the transition to a HFHS lowered cage activity in VCD mice. A chronic HFHS diet (16 weeks) significantly increased weight gain, fat mass, and hepatic steatosis in VCD-treated mice compared to HFHS-fed controls. In the liver, VCD mice showed suppressed hepatic mitochondrial respiration on LFD, while chronic HFHS diet resulted in compensatory increases in hepatic mitochondrial respiration. Also, liver RNA sequencing revealed that VCD promoted global upregulation of hepatic lipid/cholesterol synthesis pathways. Our findings suggest that the VCD- induced menopause model compromises hepatic mitochondrial function and lipid/cholesterol homeostasis that sets the stage for HFHS diet-induced steatosis while also increasing susceptibility to obesity.

physiology↗

bioRxiv2023

In vitro reconstitution reveals membrane clustering and double-stranded RNA recruitment by the enteroviral AAA+ ATPase 2C

Enteroviruses are a vast genus of positive-sense RNA viruses that cause diseases ranging from common cold to poliomyelitis and viral myocarditis. They encode a membrane-bound AAA+ ATPase, 2C, that has been suggested to serve several roles in virus replication, e.g. as an RNA helicase and capsid assembly factor. Here, we report the reconstitution of full-length, poliovirus 2Cs association with membranes. We show that the N-terminal membrane-binding domain of 2C contains a conserved glycine, which is suggested by structure predictions to divides the domain into two amphipathic helix regions, which we name AH1 and AH2. AH2 is the main mediator of 2C oligomerization, and is necessary and sufficient for its membrane binding. AH1 is the main mediator of a novel function of 2C: clustering of membranes. Cryo-electron tomography reveal that several 2C copies mediate this function by localizing to vesicle-vesicle interfaces. 2C-mediated clustering is partially outcompeted by RNA, suggesting a way by which 2C can switch from an early role in coalescing replication organelles and lipid droplets, to a later role where 2C assists RNA replication and particle assembly. 2C is sufficient to recruit RNA to membranes, with a preference for double-stranded RNA (the replicating form of the viral genome). Finally, the in vitro reconstitution revealed that full-length, membrane-bound 2C has ATPase activity and ATP-independent, single-strand ribonuclease activity, but no detectable helicase activity. Together, this study suggests novel roles for 2C in membrane clustering, RNA membrane recruitment and cleavage, and calls into question a role of 2C as an RNA helicase. The reconstitution of functional, 2C-decorated vesicles provides a platform for further biochemical studies into this protein and its roles in enterovirus replication.

microbiology↗

bioRxiv2023

Chemogenetic inhibition of IST1-CHMP1B interaction impairs endosomal recycling and promotes unconventional LC3 lipidation at stalled endosomes

The Endosomal Sorting Complex Required for Transport (ESCRT) machinery constitutes a multisubunit protein complex that plays an essential role in membrane remodeling and trafficking. ESCRTs regulate a wide array of cellular processes, encompassing cytokinetic abscission, cargo sorting into multivesicular bodies (MVBs), membrane repair and autophagy. Given the versatile functionality of ESCRTs and the intricate organizational structure of the ESCRT complex, the targeted modulation of distinct ESCRT-mediated membrane deformations for functional dissection poses a considerable challenge. This study presents a pseudo-natural product targeting IST1-CHMP1B within the ESCRT-III complex. This compound specifically disrupts the interaction between IST1 and CHMP1B, thereby inhibiting the formation of IST1-CHMP1B copolymers essential for normal-topology membrane scission events. While the compound has no impact on cytokinesis, MVB sorting and exosome biogenesis, it rapidly hinders transferrin receptor (TfR) recycling in cells, resulting in the accumulation of transferrin in perinuclear endosomal recycling tubules. Stalled recycling endosomes acquire unconventional LC3 lipidation, establishing a link between non-canonical LC3 lipidation and endosomal recycling.

cell biology↗

bioRxiv2022

Individual differences in oxycodone addiction-like behaviors in a large cohort of heterogeneous stock (HS) rats

Family and twin studies demonstrate that genetic factors determine 20-60% of the vulnerability to opioid use disorder. However, the genes/alleles that mediate the risk of developing addiction-related behaviors, including the sensitivity to the analgesic efficacy of opioids, the development of tolerance, dependence, and escalation of oxycodone taking and seeking, have been ill-defined, thus hindering efforts to design pharmacological interventions to enable precision medicine strategies. Here we characterized oxycodone addiction-like behaviors in heterogeneous stock (HS) rats, that show high genetic diversity that mimics the high genetic variability in humans. HS rats were allowed to self-administer oxycodone for two h/daily for four days (ShA) and then moved to 12h/daily (LgA) for 14 days. Animals were screened for motivation to self-administer oxycodone using a progressive-ratio (PR) schedule of reinforcement and for the development of withdrawal-induced hyperalgesia and tolerance to the analgesic effects of oxycodone using the von-Frey and tail immersion tests, respectively. To reduce cohort-specific effects, we used cohorts of 46-60 rats and normalized the response level within cohorts using a Z-score. To take advantage of the four opioid-related behaviors and further identify subjects that are consistently vulnerable vs. resilient to compulsive oxycodone use, we computed an Addiction Index by averaging normalized responding (Z-scores) for the four behavioral tests. Results showed high individual variability between vulnerable and resilient rats, likely to facilitate the detection of gene variants associated with vulnerable vs. resilient individuals. Such data will have considerable translational value for designing follow-up studies in humans.

neuroscience↗

bioRxiv2022

Identification of individual differences in response to methadone, buprenorphine, and naltrexone in animal models of opioid use disorder

RationaleCurrent medications for opioid use disorder include buprenorphine, methadone, and naltrexone. While these medications show significant efficacy in reducing craving and opioid use, there are substantial individual differences in response to these treatments in humans. The reason for such difference is poorly known. ObjectivesHere, we tested the hypothesis that similar individual differences may be observed in a large population of heterogenous stock rats, that have been bred to maximize genetic diversity, using a behavioral paradigm relevant to opioid use disorder. MethodsOver 500 rats were given intermittent (4d/week) and extended access (12h/day) to oxycodone self-administration for 14 sessions to establish oxycodone dependence and escalation of intake. We then measured the effect of buprenorphine (0.5mg/kg), methadone (3mg/kg) and naltrexone (3mg/kg) on the motivation to self-administer oxycodone by using a progressive ratio schedule of reinforcement. ResultsWe found that naltrexone and buprenorphine significantly decreased motivation to oxycodone rewards. While naltrexone reduced oxycodone intake in both males and females, systemic administration with buprenorphine reduced progressive ratio responses only in males. Methadone reduced motivation to oxycodone self-administration in nearly 25% of the population, without reaching statical significance. Our results showed that the efficacy of these medications depends on the severity of addiction like behaviors, indicated by the addiction index. ConclusionsThese results demonstrate individual differences in response to medications to treat opioid use disorder in a genetically diverse population of rats.

neuroscience↗

bioRxiv2021

In situ structures of membrane-assisted assembly and selective autophagy of enteroviruses

Enteroviruses are non-enveloped positive-sense RNA viruses that cause diverse diseases in humans. Their rapid multiplication depends on remodeling of cytoplasmic membranes for viral genome replication. It is unknown how virions assemble around these newly synthesized genomes and how they are then loaded into autophagic membranes for release through secretory autophagy. Here, we use cryo-electron tomography of infected cells to show that poliovirus assembles directly on replication membranes. Pharmacological untethering of capsids from membranes abrogates RNA encapsidation. Our data directly visualize a membrane-bound half-capsid as a prominent virion assembly intermediate. Assembly progression past this intermediate depends on the class III phosphatidylinositol 3-kinase VPS34, a key host-cell autophagy factor. On the other hand, the canonical autophagy initiator ULK1 is shown to restrict virion production since its inhibition leads to increased accumulation of virions in vast intracellular arrays, followed by an increased vesicular release at later time points. Finally, we identify multiple layers of selectivity in virus-induced autophagy, with a strong selection for RNA-loaded virions over empty capsids and the segregation of virions from other types of autophagosome contents. These findings provide an integrated structural framework for multiple stages of the poliovirus life cycle.

microbiology↗

bioRxiv2021

Characterization of cocaine addiction-like behavior in heterogeneous stock rats

Addiction is commonly characterized by escalation of drug intake, compulsive drug seeking, and continued use despite harmful consequences. However, the factors contributing to the transition from moderate drug use to these problematic patterns remain unclear, particularly regarding the role of sex. Many preclinical studies have been limited by small sample sizes, low genetic diversity, and restricted drug access, making it challenging to model significant levels of intoxication or dependence and translate findings to humans. To address these limitations, we characterized addiction-like behaviors in a large sample of >500 outbred heterogeneous stock (HS) rats using an extended cocaine self-administration paradigm (6 h/daily). We analyzed individual differences in escalation of intake, progressive-ratio (PR) responding, continued use despite adverse consequences (contingent foot shocks), and irritability-like behavior during withdrawal. Principal component analysis showed that escalation of intake, progressive ratio responding, and continued use despite adverse consequences loaded onto a single factor that was distinct from irritability-like behaviors. Categorizing rats into resilient, mild, moderate, and severe addiction-like phenotypes showed that females exhibited higher addiction-like behaviors, with a lower proportion of resilient individuals compared to males. These findings suggest that, in genetically diverse rats with extended drug access, escalation of intake, continued use despite adverse consequences, and PR responding are highly correlated measures of a shared underlying construct. Furthermore, our results highlight sex differences in resilience to addiction-like behaviors.

neuroscience↗

bioRxiv2021

Leptin protects against the development and expression of cocaine addiction-like behavior in heterogenous stock rats

In addition to its pleasurable effects, weight control is a significant contributor to initiation, maintenance and relapse of cocaine use. This suggests that individual differences in bodyweight control and feeding hormones, such as leptin may contribute to the vulnerability to cocaine use disorder. While pre-clinical studies have shown a mutually inhibitory relationship between leptin and cocaine, they have used small sample sizes and did not investigate individual differences in a large heterogeneous population. Here, we tested if individual differences in bodyweight and blood leptin level is associated with high or low vulnerability to addiction-like behaviors using data from 500 heterogenous stock rats and 160 blood samples from the Cocaine Biobank, using a model of extended access to intravenous self-administration of cocaine. Finally, we tested a separate cohort to evaluate the causal effect of exogenous leptin administration on cocaine seeking. Bodyweight, while changing due to cocaine self-administration in males, was not related to the vulnerability to addiction-like behavior. Blood leptin levels after ~6 weeks of cocaine self-administration did not correlate with addiction-like behaviors, however, baseline blood leptin levels before any access to cocaine negatively predicted addiction-like behavior. Finally, administration of leptin reduced cocaine intake after acute withdrawal and cocaine seeking after 6 weeks of protracted abstinence. These results demonstrate that high blood leptin level before access to cocaine may be a protective factor against the development of cocaine addiction-like behavior, that exogenous leptin reduces the motivation to take and seek cocaine, but that blood leptin level and bodyweight changes in current users are not good biomarkers for addiction-like behaviors.

physiology↗

bioRxiv2020

A Two-Step Bioreactor for Lung Recellularization

Bioreactors for reseeding of decellularized lung scaffolds have evolved with a wide variety of advancements. These include biomimetic mechanical stimulation, constant nutrient flow, multi-output monitoring, and large mammal scaling. Although dynamic bioreactors are not new to the field of bioengineered lungs, ideal conditions during cell seeding have not been extensively studied or controlled. To address the lack of cell dispersal in traditional seeding methods, we have designed a two-step bioreactor. The first step rotates a seeded lung every 20 minutes at different angles to ensure 20 percent of cells are anchored to a particular location based on the known rate of attachment. The second step involves perfusion culture to ensure nutrient dispersion and cellular growth. Compared to statically seeded lungs followed by conventional perfusion, rotationally seeded lungs followed by perfusion had significantly increased dsDNA content and more uniform cellular distribution. This new bioreactor system will aid in recellularizing the lung and other geometrically complex organs for tissue engineering.

bioengineering↗

bioRxiv2020

Microstructural meal pattern analysis reveals that nicotine is a potent anti-anorectic drug despite producing long-term anorexigenic effects

Nicotine consumption in both human and animal studies has been strongly associated with changes in feeding-related behaviors and metabolism. The current dogma is that chronic nicotine decreases food intake and increases metabolism, leading to lower body weight. However, the effect of acute nicotine intake on feeding is unclear. The present study employed microstructural and macrostructural behavioral analyses to elucidate changes in feeding behavior in animals that intravenously self-administered nicotine. At the microstructural level (seconds to minutes), nicotine increased feeding and drinking behavior during the first 5 minutes after nicotine self-administration. This effect was also observed in animals that passively received nicotine, but the effect was not observed in animals that self-administered saline or passively received saline. At the macrostructural level (hours to days), nicotine decreased body weight gain, decreased feeding, and was associated with increases in feeding and body weight gain during abstinence. These results suggest that nicotine first produces anti-anorectic effects before producing long-term anorexigenic effects. These results challenge the notion that nicotine is an anorexigenic drug and paradoxically suggest that the anorexigenic effects of nicotine may be a long-term consequence of acute anti-anorectic effects of nicotine.

physiology↗

bioRxiv2019

Laminin-driven Epac/Rap1 regulation of epithelial barriers on decellularized matrix

Decellularized tissues offer a unique tool for developing regenerative biomaterials or in vitro platforms for the study of cell-extracellular matrix (ECM) interactions. One main challenge associated with decellularized lung tissue is that ECM components can be stripped away or altered by the detergents used to remove cellular debris. Without characterizing the composition of lung decellularized ECM (dECM) and the cellular response caused by the altered composition, it is difficult to utilize dECM for regeneration and specifically, engineering the complexities of the alveolar-capillary barrier. This study takes steps towards uncovering if dECM must be enhanced with lost ECM proteins to achieve proper epithelial barrier formation. To achieve this, epithelial barrier function was assessed on dECM coatings with and without the systematic addition of several key basement membrane proteins. After comparing barrier function on collagen, fibronectin, laminin, and dECM in varying combinations as an in vitro coating, the alveolar epithelium exhibited superior barrier function when dECM was supplemented with laminin as evidenced by trans-epithelial electrical resistance (TEER) and permeability assays. Increased barrier resistance with laminin addition was associated with upregulation of Claudin-18, E- cadherin, and junction adhesion molecule (JAM)-A, and stabilization of zonula occludens (ZO)-1 at junction complexes. The Epac/Rap1 pathway was observed to play a role in the ECM-mediated barrier function determined by protein expression and Epac inhibition. These findings reveal potential ECM coatings and molecular therapeutic targets for improved regeneration with decellularized scaffolds or edema related pathologies.

bioinformatics↗

bioRxiv2017

The Influence of Aging and Mechanical Stretch in Alveolar Epithelium ER Stress and Inflammation

Ventilator-Induced lung injury (VILI) is a form of acute lung injury that is initiated or exacerbated by mechanical ventilation. The aging lung is more susceptible to lung injury. Harmful mechanical stretch of the alveolar epithelium is a recognized mechanism of VILI, yet little is known about how mechanical stretch affects aged epithelial cells. An activated response known as Endoplasmic Reticulum (ER) Stress occurs at the cellular level, which is increased with aging. The disrupted ER function results in disruption in cellular homeostasis, apoptosis, and inflammation. We hypothesized that age and mechanical stretch increase proinflammatory gene expression that is mediated by ER stress. Type II alveolar epithelial cells (ATII) were harvested from C57Bl6/J mice 8 weeks (young) and 20 months (old) of age. The cells were cyclically mechanically stretched at 15% change in surface area for up to 24 hours. Prior to stretch, groups were administered 4-PBA or vehicle as a control. Mechanical stretch upregulated both ER stress and proinflammatory gene expression in ATIIs. Age-matched and mis-matched monocyte recruitment by ATII conditioned media was quantified. Administration of 4-PBA attenuated both the ER stress and proinflammatory increases from stretch and/or age and significantly reduced monocyte migration to ATII conditioned media. Age increases susceptibility to stretch-induced ER stress and downstream inflammation in a primary ATII epithelial cell model.

bioengineering↗