Druliner, Brooke R.

Age-related gastrointestinal dysfunction is common, but the mechanisms of aging-associated smooth muscle failure remain unclear. We show that aging in mice slows whole gut and colonic transit, increases regional stiffness, and reduces smooth muscle contractility. Inducible smooth muscle cell (SMC)– specific deletion of Piezo1 preserved youthful transit and force generation, whereas Piezo1 activation in young mice phenocopied aging-associated transit delay. Single-cell transcriptomics, RNA velocity, stiffness-controlled cell and tissue cultures, and pharmacologic studies revealed that Piezo1 couples increased stiffness to Ca 2+ –calcineurin–NFAT signaling, loss of contractile gene programs, leading to age- related contractile loss and contractile-to-synthetic SMC remodeling and gut wall stiffening. Human intestinal SMCs supported conservation of this pathway, and PIEZO1 gain-of-function carriers showed a trend toward delayed colonic transit. Thus, maladaptive SMC Piezo1 mechanotransduction is a targetable mechanism of aging-associated gut dysmotility. Aging alters organ structure, yet how these changes drive functional decline remains poorly defined. We show that progressive stiffening of the gut with age activates the mechanosensitive ion channel Piezo1 in smooth muscle cells, initiating a maladaptive response that impairs contractility and slows intestinal transit. On the other hand, deletion of smooth muscle Piezo1 prevents age-related gut dysmotility. These findings reveal that age-related physical shifts actively drive functional decline through mechanotransduction pathways. By identifying Piezo1 as a critical link between tissue mechanics and organ aging, this work provides a framework for understanding how mechanical cues contribute to age-related dysfunction in the gut and possibly other smooth muscle organs.

The intestinal epithelium is exposed to diverse combinations of microbiota-derived compounds; however, the mechanisms by which the host integrates these signals remain poorly defined. Studying two highly abundant microbial metabolites, we identified the purine metabolite hypoxanthine as an effector metabolite that directly drives signaling and the short-chain fatty acid butyrate as a regulatory metabolite that conditions host responsiveness. Specifically, hypoxanthine activates the adenosine A1 receptor–TRPC4 axis in enterochromaffin (EC) cells, triggering calcium influx and serotonin release resulting in accelerated gastrointestinal transit locally and increased platelet activation systemically. In contrast, butyrate epigenetically upregulates specific G protein–coupled receptors and ion channels to enhance response to hypoxanthine and the neurotransmitters norepinephrine and dopamine. These findings define a cooperative signaling framework and highlight the role of EC cells as a distinct epithelial signaling hub that senses and integrates microbial metabolite signals to drive physiological responses. Our findings provide a mechanistic foundation for therapeutic strategies that leverage combinatorial microbial signaling.

Abstract Background: Aberrations in telomere length have important implications in cancer development and progression. This study aimed to determine whether leukocyte telomere length (LTL) in patients with colorectal cancer (CRC) is associated with survival outcomes. We also investigated whether genetic variants in telomere maintenance genes are associated with survival in these patients. Methods: Blood specimens were collected from 1,007 patients prior to receiving chemotherapy or radiation. Genomic DNA was extracted using the Promega Maxwell RSC instrument. LTL was measured in triplicate using monochrome multiplex PCR, where the average amplification value of telomeric repeats was termed T. Similarly, PCR amplification of a single-copy reference gene was performed, and its average amplification value was termed S. The telomere length for each sample was expressed as the T/S ratio. Genotyping of single-nucleotide polymorphisms (SNPs) in TERC, TERT, and OBFC1 genes was conducted at the institutional Genome Analysis Core facility. Kaplan-Meier survival curves were generated to evaluate patient survival outcomes. Results: Younger individuals (∼25 years) exhibited nearly a twofold longer LTL compared with older individuals (∼75 years). No significant difference in LTL was observed between stage II and stage III CRC patients. A strong inverse correlation was observed between patient age and LTL (Spearman’s r = -0.48; p = 1.13 × 10-58). Females had significantly longer LTL than males (p = 3.97 × 10-5). The TERC SNP rs1317082 was significantly associated with both overall survival (OS) and disease-free survival (DFS) in the combined stage II and stage III patient cohort (p = 0.017 and p = 0.023, respectively). Similarly, the OBFC1 SNP rs9419958 was significantly associated with OS (p = 0.016). Importantly, LTL itself was significantly associated with both OS and DFS (p = 0.008 and p = 0.044, respectively) among the combined stage II and stage III patients. Kaplan-Meier survival analyses demonstrated that age- and sex-adjusted LTL was predictive of long-term survival outcomes. Conclusions: Survival among patients with stage II and III colorectal cancer is significantly influenced by LTL. Additionally, specific allelic variants of telomere maintenance genes, including TERC and OBFC1, are independently associated with improved survival, irrespective of LTL. These findings suggest that peripheral blood LTL measurement, along with telomere-related genotyping, may serve as a valuable prognostic marker for colorectal cancer outcomes. Funding: Individualizing colorectal cancer patient care using the host and tumor telomere phenotype (RO1 CA204013), Curtiss Fund (92541775), C-SiG Core(s): Epigenomics & Spatial Biology Core, and Clinical Core of the Mayo Clinic Center for Cell Signaling in Gastroenterology (P30DK084567) Citation Format: Estela M. Cruz Garcia, Gobinda Sarkar, Jun Chen, Shubham Sood, Kim Kossick, Daniel Schupack, Rondell Graham, Brooke Druliner, Zahra Heydari, Lauren Helgeson, Richard G. Cawthon, Lisa A. Boardman. Longer leukocyte telomeres and specific alleles of telomere maintenance genes are independently associated with improved survival of colon cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 1919.

Background and aims: Aberrations in telomere length can have important implications in cancer. Using a cohort of 1007 patients, we investigated whether leukocyte telomere length (LTL) in patients with colorectal cancer (CRC) is associated with survival. We also investigated whether some telomere maintenance genes are associated with survival in these patients. Methods: The Biobank for Gastrointestinal Health Research (BGHR), an ongoing project involving collection of biospecimens at the Mayo Clinic, was utilized to obtain data from patients diagnosed with stage II or III CRC. Blood samples were collected prior to chemotherapy/radiation and DNA was extracted for measuring median LTL. The main outcome measures were overall survival (OS) and disease-free survival (DFS) by disease stage. Results: A significant inverse relationship was observed with patient age and LTL (spearman correlation coefficient (r) = −0.48, 95%; p = 1.13 × 10−58). Females had significantly longer LTL than males (p = 3.97 × 10−5). The rs1317082 SNP in the TERC gene was significantly associated with both OS and DFS in combined stage II and stage III patients (p = 0.017 and p = 0.023, respectively). A statistically significant association of the OBFC1 SNP (rs9419958) was observed for OS for the combined stage II and stage III patients (p = 0.016). Importantly, LTL was significantly associated with both OS and DFS (p = 0.008 and 0.044 respectively) in combined stage II and stage III patients. Conclusions: Our results show that LTL is predictive of OS and DFS for stage II and III CRC patients, particularly over a longer follow-up, extending beyond five years after a diagnosis of CRC, and certain SNPs in genes involved in telomere maintenance are significantly associated with patient outcomes, independent of telomere length.

This study reveals a novel role for Treg-derived IL-6R in supporting epithelial repair. Despite preserved immune-suppressive capacity, deletion of IL-6R from Tregs impairs epithelial transcription and worsens injury in colitis. We demonstrate that human intestinal organoids preferentially respond to trans- over classic IL-6 signaling. These findings introduce a Treg-specific role in immune-epithelial cross talk relevant to mucosal healing and inflammatory bowel disease.

Piezo2 is a mechanically gated ion channel most commonly expressed by specialized mechanoreceptors, such as the enteroendocrine cells (EECs) of the gastrointestinal epithelium. A subpopulation of EECs expresses Piezo2 and functionally resembles the skin’s touch sensors, called Merkel cells. Low-magnitude mechanical stimuli delivered to the mucosal layer are primarily sensed by mechanosensitive EECs in a process we term “gut touch.” Piezo2 transduces cellular forces into ionic currents, a process that is sensitive to bilayer tension and cytoskeletal depolymerization. E-cadherin is a widely expressed protein that mediates cell–cell adhesion in epithelia and interacts with scaffold proteins that anchor it to actin fibers. E-cadherin was shown to interact with Piezo2 in immortalized cell models. We hypothesized that the Piezo2–E-cadherin interaction is important for EEC mechanosensitivity. To test this, we used super-resolution imaging, co-immunoprecipitation, and functional assays in primary tissues from mice and gut organoids. In tissue EECs and intestinal organoids, we observed multiple Piezo2 cellular pools, including one that overlaps with actin and E-cadherin at the cells’ lateral walls. Further, E-cadherin co-immunoprecipitated with Piezo2 in the primary colonic epithelium. We found that E-cadherin knockdown decreases mechanosensitive calcium responses in mechanically stimulated primary EECs. In all, our results demonstrate that Piezo2 localizes to the lateral wall of EECs, where it physically interacts with E-cadherin and actin. They suggest that the Piezo2–E-cadherin–actin interaction is important for mechanosensitivity in the gut epithelium and possibly in tissues where E-cadherin and Piezo2 are co-expressed in epithelial mechanoreceptors, such as skin, lung, and bladder.

Background Obstructive sleep apnea (OSA) increases the risk for metabolic and cardiovascular disease. Telomere shortening has been linked to hypertension, diabetes mellitus, and cardiovascular diseases such as stroke and myocardial infarction. Because these conditions are highly prevalent in sleep apnea, we hypothesized that telomere length (TL) would be reduced in patients with OSA. Methods Genomic DNA was isolated from circulating leukocytes in 176 subjects (42.8 ± 13.8 years, 22.7 % women) who had undergone overnight polysomnographic evaluation. Of these individuals, 92 subjects had an Apnea Hypopnea Index (AHI) >5 events/hour and were classified as OSA patients. TL was measured using a quantitative PCR where a telomere to single copy gene ratio is determined and represented as number of base pairs (bp). The effect of OSA on TL was determined by comparing a control group (no OSA) (AHI<5, n=92) with patients with mild OSA (≥ 5 AHI <15, n=25), and those with moderate to severe OSA (AHI ≥15, n=59) in unadjusted and age‐adjusted models. Results Compared to control subjects, mild and moderate to severe OSA subjects were older: 48.9 ± 11.2 vs. 36.0 ± 11.2 years (p<0.001) and 50.8 ± 13.1 vs. 36.0 ± 11.2 years (p<0.001), respectively. Statistical models examining the effects of OSA severity on TL showed a J‐shaped curve : longer TL in moderate to severe OSA (4867 ± 221 bp) and controls (4820 ± 160 bp), and the shortest TL in mild OSA (4742 ± 155 bp). The mean TL in moderate to severe OSA was significantly longer than in mild OSA (p=0.0048). These effects were more pronounced after adjustment for age, when we observed significant differences in mean TL between moderate to severe OSA and mild OSA (p=0.0036) and between moderate to severe OSA and the control group (p=0.0379) (). However, the mean TL between control subjects and subjects with mild OSA was not different. Conclusion Moderate to severe OSA patients had longer TL compared with mild OSA and control group. This association was independent of age. Even though OSA is associated with increased cardiovascular risk, telomere lengthening in subjects with moderate to severe OSA suggests the presence of protective compensatory mechanisms to prevent telomere shortening in OSA. On the other hand, the existence of longer telomere in subjects with moderate and severe OSA may also indicate triggering of molecular mechanisms which may contribute to cancer development. Further studies are needed to explain the role of hypoxia in telomere dynamics in OSA, and the interactions between telomere length and increased longevity reported in older patients with OSA. Support or Funding Information NIH R01 grant (#HL65176); Singh P. is supported by AHA scientist development grant (11SDG7260046). Becari C. is supported by grant from CNPq‐Brazil (# 203802/2014‐4).

Abstract Organs that face external environments, such as skin and gut, are lined by epithelia, which have two functions – to provide a semi-permeable barrier and to sense stimuli. The intestinal lumen is filled with diverse chemical and physical stimuli. Intestinal epithelial cells sense these stimuli and signal to enteric neurons which coordinate a range of physiologic processes required for normal digestive tract function. Yet, the neuro-epithelial connections between intestinal epithelial cells and enteric neurons remain poorly resolved, which leaves us with limited mechanistic understanding of their function. We describe the development of a two-compartment microfluidic device for modeling neuro-epithelial interactions, and apply it to form the gut’s neuro-epithelial connections. The device contains epithelial and neuronal compartments connected by microgrooves. The epithelial compartment was designed for cell seeding via injection and confinement of intestinal epithelial cells derived from human intestinal organoids. We demonstrated that organoids planarized effectively and retained epithelial phenotype for over a week. In the second chamber we dissociated and cultured intestinal myenteric neurons including intrinsic primary afferent neurons (IPANs) from transgenic mice that expressed the fluorescent protein tdTomato. IPANs extended projections into microgrooves, surrounded and frequently made contacts with epithelial cells. The density and directionality of neuronal projections were enhanced by the presence of epithelial cells in the adjacent compartment. Our microfluidic device represents a platform for dissecting structure and function of neuro-epithelial connections in the gut and other organs (skin, lung, bladder, and others) in health and disease.

Traditionally regarded as a consequence of sleep‐disordered breathing, excessive daytime sleepiness (EDS) is now recognized as an independent risk factor for cardiovascular disease. Evidence also links the shortening of telomeres, responsible for protecting DNA, with increased cardiovascular disease risk. Interestingly, recent data illustrate telomere lengthening in patients with obstructive sleep apnea (OSA); however, whether EDS is associated with telomere length independently of OSA remains unknown. To examine this potential relationship, we studied 169 subjects with polysomnography assessment who answered “yes” or “no” to experiencing EDS; 70 subjects (41%) reported EDS (59M, 44±12yrs, 30.3±5.5kg/m 2 ) whereas 99 did not (59%, 71M, 40±15yrs, 28.6±7.5kg/m 2 ). Telomere length was quantified via qPCR of genomic DNA isolated from peripheral blood samples and did not differ between individuals reporting EDS compared to those who did not (4,856±280 vs. 4,880±340bp, respectively, P =0.31). However, 50% of subjects reporting EDS had moderate‐to‐severe OSA (apnea‐hypopnea index ≥15events/hr) compared to 28% of the non‐EDS group ( P <0.01). To account for the confounding effects of OSA on telomere length, we conducted a series of subgroup analyses. Subjects without OSA who reported EDS (n=35, 27M, 39±11yrs, 27.4±5.0kg/m 2 ) had shorter telomeres (4,805±165 vs. 4,875±231bp, P =0.05) than those not reporting EDS (n=71, 47M, 35±11yrs, 26.8±5.4kg/m 2 ). Interestingly, within the OSA subgroup, there were no differences in telomere length (4,897±235 vs. 4,858±251bp, P =0.45) between those with (n=35, 32M, 48±11yrs, 33.2±4.5kg/m 2 ) and without EDS (n=28, 24M, 53±16yrs, 33.1±9.7kg/m 2 ). These effects do not appear to be influenced by subject demographics as no differences were found between compared groups (EDS‐OSA vs. nEDS‐OSA and OSA+EDS vs. OSA‐EDS). Collectively, our data suggest individuals reporting EDS may be at greater risk of developing cardiovascular disease due to accelerated telomere shortening. It also appears OSA and EDS exert differential effects on telomere length.

Abstract Colon polyps are the most common neoplastic finding at colonoscopy and have the potential to transform to cancer. Understanding the mechanisms involved in the transformation from normal colon to polyp is central to the identification of interventions to prevent or stop a polyp from forming or, in the worst case, from transforming. Therefore, the clinical conundrum is to predict which polyps will progress. It is crucial to understand if there are molecular features that define premalignant lesions and that may contribute to the final steps of transformation, which could potentially be targets for early detection or more individualized clinical management. Cellular transformation is driven by the interplay of genetic and epigenetic changes, and a large body of research has identified modifications of chromatin and the role of those modifications in regulating genes. Telomeres, telomere maintenance mechanisms, and chromatin remodelers maintain genetic stability, and their disruption is associated with the development of many diseases, including cancer. Organoids are multicellular structures grown from the stem cells of an organ to recapitulate the diverse cell types of the parent organ. This renewable resource of an individual’s tissue provides the opportunity to study colon carcinogenesis in combination with advanced genomic tools such as gene editing. The overall objective of this study is to determine the role of telomere and chromatin remodeler alterations in neoplastic transformation. The functional interaction between hTERT and specific chromatin remodelers will be resolved in two steps: 1) activating telomerase in normal colon and polyp organoids from patients and measuring chromatin remodeler expression, and 2) incorporating mutations in the chromatin remodelers using genome editing and then measuring the expression of hTERT in the normal colon and polyp organoids from patients with cancer-adjacent and cancer-free polyps. Gene editing experiments were performed utilizing transposon-based vectors (PiggyBac), short homology arm-based knockin (GeneWeld), or CRISPR/Cas9, coupled with electroporation for cargo delivery. To assess neoplastic transformation as a result of the gene edits, we used histology and cellular morphology of the organoid specimen by hematoxylin and eosin staining and pathologist review, and the markers by immunofluorescence. These models of neoplastic transformation in organoids from patient tissues provide an accessible tool to visualize the functional changes that correspond to alterations in telomerase and chromatin remodelers and how alterations in these targets affect growth, proliferation, differentiation, and cell turnover. Identification of epigenomic molecular alterations linked with progression of polyps to cancer could lead to modifiable targets for preventive interventions and provide candidate molecular markers in order to better tailor polyp patient screening recommendations. Note: This abstract was not presented at the conference. Citation Format: Brooke R. Druliner, Brandon Simone, Miguel Munoz-Gomez, Kim Kossick, Daniel O'Brien, Alexej Abyzov, Stephen Ekker, Lisa A. Boardman. Characterizing telomere and chromatin dynamics in colorectal cell transformation [abstract]. In: Proceedings of the AACR Special Conference on the Evolving Landscape of Cancer Modeling; 2020 Mar 2-5; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2020;80(11 Suppl):Abstract nr A33.