bluuebunny/crossref_metadata_2025 huggingface dataset:
Altered Inflammatory Responses In Tobacco Smoke‐Exposed Mice That Over‐Express The Tight Junctional Protein Claudin‐6
Authors: Lewis Joshua B , Bodine Jared , Milner Dallin , Lewis Adam , Dunaway Todd , Egbert Kaleb , Albright Scott , Merrill Brigham , Monson Troy , Watson Mark , Burstedt Nathan , Smith Quinn , Gassman Jason , Jergensen Tyson , Chavarria Bryan , Broberg Dallin , Thomas Daniel , Arroyo Juan , Reynolds Paul R
Published: November 2023

It has long been understood that increased epithelial permeability contributes to mucosal inflammation associated with many respiratory diseases including COPD, emphysema, and acute lung injury (ALI). Recently, evidence has revealed that environmental exposures to noxious material such as air pollution, allergens, and cigarette smoke reduces tight junction barrier integrity, thus contributing to inflammatory conditions. Cldn6 is a tetraspanin transmembrane protein found within the tight junctional complex and is implicated in maintaining lung epithelial barriers. To elucidate the role of Cldn6, we utilized the Tet‐O inducible system to conditionally over‐express Clnd6 within the distal lung. Cldn6 TG and control mice were continuously provided doxycycline from postnatal day (PN) 30 until sacrifice date at PN 90 and lung biology was assessed. A subset of Cldn6 TG and control mice were also subjected to daily secondhand tobacco smoke (SHS) via a nose only inhalation system (Sireq industries) from PN30‐90. On the sacrifice date, lungs were harvested for histological and molecular characterization. Bronchoalveolar lavage fluid (BALF) was procured for the assessment of inflammatory cells and molecules. qPCR and immunoblotting revealed increased Cldn6 expression in TG vs. control animals and SHS decreased Cldn6 expression regardless of genetic up‐regulation in TG mice. Immunohistochemistry and immunoblotting confirmed the differential expression of Cldn6 and a host of cell‐specific and inflammatory markers (TNF‐alpha, IL‐1beta, Pro‐SPC, CCSP, FOXJ1, and MAC3). As a general theme, inflammation induced by SHS exposure was influenced by the availability of Cldn6. These data reveal captivating information suggesting a role for Cldn6 in lungs exposed to tobacco smoke and further research is necessary in order to fully explain roles for TJ components such as Cldn6 in lungs coping with exposure.

Support or Funding Information

This work was supported by a grant from the Flight Attendant's Medical Research Institute (FAMRI, PRR) and a BYU Mentoring Environment Grant (PRR).
Th1 Effector T cells Induce Cardiac Fibroblasts Transition to Myofibroblasts and Contribute to Pressure Overload Induced Cardiac Fibrosis
Authors: Nevers Tania , Salvador Ane M , Velazquez Francisco , Aronovitz Mark , Blanton Robert , Alcaide Pilar
Published: November 2023

Cardiac fibrogenesis is a major pathogenic factor that occurs in heart failure (HF) and results in contractile dysfunction and ventricular dilation. It is known that various inflammatory mediators such as T cells and pro‐fibrotic cytokines play an important part in triggering fibrosis in many different organ systems. We recently demonstrated that T cells represent a major subset of heart infiltrating cells in pressure overload induced heart failure, and contribute to cardiac fibrosis and HF progression. In fact, mice deficient in T cells (TCRa−/− mice) or pharmacological depletion of T cells in WT mice resulted in blunted cardiac fibrosis and preserved cardiac function. However the mechanism by which T cells contribute to cardiac fibrosis and the pathogenesis of non‐ischemic HF is still unclear. Thus, we hypothesize that heart infiltrated T cells perpetuate the fibrotic response by regulating the differentiation and activation of extracellular matrix‐producing cardiac myofibroblasts. To test this hypothesis we used in vitro approaches and the thoracic aortic constriction (TAC) mouse model of pressure overload induced heart failure. Co‐culture of various CD4 T cell subsets with cardiac fibroblasts demonstrated that Th1 cells, in contrast to naïve T cells, adhered directly to cardiac fibroblasts and induced fibroblast to myofibroblast transition, enhancing collagen secretion and regulating the synthesis of extracellular matrix proteins shown to be implicated in fibrosis. Supernatants of Th1 cells only slightly induced myofibroblast transition, indicating the requirement of Th1 cells cross‐talk to cardiac fibroblasts to promote fibrosis. Adoptive transfer of Th1 cells into TCRa−/− mice at 48 hours and 2 weeks post TAC surgery resulted in T cell LV infiltration and was sufficient to induce left ventricular fibrosis, and this was not observed after adoptive transfer of naïve T cells in the onset of TAC. Our data suggest that Th1 cells and cardiac fibroblasts reciprocally influence cardiac fibrosis and the pathogenesis of heart failure. These findings provide an attractive tool to counteract the inflammatory/fibrotic process as an alternative option for the treatment of cardiac fibrosis in non ischemic heart failure.

Support or Funding Information

NIH HL094706 and AHA 13GRNT14560068 (PA), HL6977(RHK )
High glucose culture medium downregulates production of human β‐defensin‐2 (HBD‐2) in human amniotic epithelial cells (HAEC)
Authors: Szukiewicz Dariusz , Alkhalayla Habib , Pyzlak Michal , Szewczyk Grzegorz
Published: November 2023

Protection of materno‐placento‐fetal unit significantly depends on production of β‐defensins, including HBD‐2, by the HAEC. Regulation of innate and adaptive immunity by HBD‐2 is related to its action against gram‐negative bacteria and chemoattraction of immature dendritic cells. Despite the fact that diabetes induces placental genes for chronic stress and inflammatory pathways, the fetus is at higher risk of transplacental transmission of infection. Here we examined influence of a high glucose environment on production of HBD‐2 in cultured HAEC. Immediately postpartum, HAEC were isolated using trypsin‐based method at 37 degrees C from the amnions obtained after 48 normal full‐term pregnancies. The material was equally divided among the two groups: group I (N = 48) – cultured in high glucose culture medium (280 mg/dl), and the control group II (N = 48) – cultured in the standard medium containing 100 mg/dl glucose, in normoxia (20% O2). After pretreatment with LPS (1 mcg/ml), HBD‐2 concentrations in the HAEC culture supernatant were assessed at determined time points (120, 132, 144, and 156 hours) using ELISA. Nonparametric Wilcoxon rank‐sum test was used and the differences between the groups were considered statistically significant if p < 0.05. We observed that high glucose environment in group I was correlated with 1.1 to 2.7‐fold decrease over time in HBD‐2 concentration in the culture supernatant, compared to group II (p < 0.05). The mean viability of cells in both groups did not differ significantly at the consecutive time points. Thus, immunosupression due to hyperglycemia in poorly controlled diabetes may predispose to perinatal infections. Further studies are needed to examine whether this inhibition of HBD‐2 production is correlated with high glucose‐induced changes in the local expression of toll‐like receptors (TLRs).

Support or Funding Information

Supported by WUM grant: 2M2‐W1‐15
Insulin Signaling Regulation of Sortilin 1 and Glut4 Storage Vesicle Formation in NIH 3T3‐L1 Adipocytes and Mouse Adipose Tissue
Authors: Li Jibiao , Matye David , Wang Yifeng , Li Tiangang
Published: November 2023

Type‐II diabetes is associated with impaired insulin‐stimulated glucose uptake into the muscle and adipose tissues. Insulin regulates glucose uptake in adipocytes and muscle cells by promoting the plasma membrane translocation of the glucose transporter 4 (Glut4)‐containing storage vesicles, which is defective in type‐II diabetes. The intracellular trafficking receptor Sortilin 1 is an essential component of the Glut4 storage vesicles in adipocytes and mediates the insulin responsiveness of Glut4 translocation to the plasma membrane. Knockdown of Sortilin 1 impaired Glut4 storage vesicle formation and resulted in Glut4 degradation in NIH 3T3‐L1 cells. The objective of this study is to investigate the effect and molecular mechanism of insulin regulation of Sortilin 1 in differentiated 3T3‐L1 adipocytes and in mouse adipose tissue. Adipose Sortilin 1 and Glut4 protein levels were determined in obese and diabetic mice. The effects of insulin and insulin signaling inhibitors on Sortilin 1 mRNA and protein levels were determined in differentiated 3T3‐L1 adipocytes. The potential role of Sortilin 1 phosphorylation in mediating insulin regulation of Sortilin 1 was further investigated. Results showed that insulin induced Sortilin 1 protein, but not mRNA, in 3T3‐L1 adipocytes. Treatment of PI3K or AKT inhibitors decreased Sortilin 1 protein, but not mRNA in 3T3‐L1 cells. In addition, treatment of pro‐inflammatory cytokine TNFα impaired Insulin signaling and decreased Sortilin 1 protein in 3T3‐L1 adipocytes. Consistently, Sortilin 1 protein was down‐regulated in the white and brown adipose of obese and diabetic mice, which was partially restored after the administration of the insulin sensitizer metformin. In addition, intraperitoneal injection of a PI3K inhibitor in lean mice caused rapid downregulation of Sortilin 1 protein in the adipose tissue without alteration of Sortilin 1 mRNA levels. LC‐MS/MS analysis further revealed novel serine phosphorylation sites on Sortilin 1 protein. Additional mechanistic studies suggest that Sortilin 1 phosphorylation affects Sortilin1 protein trafficking function and stability, and potentially mediates insulin regulation of Sortilin 1. In conclusion, we have identified Sortilin 1 as a novel target of insulin signaling in adipose tissue, and suggest that insulin resistance may be responsible for the Sortilin 1 downregulation and impaired Glut4 storage vesicle formation in obesity and diabetes.

Support or Funding Information

American Diabetes Association, NIDDK
Pancreatic Trypsin and Insulin Receptor Cleavage in High Fat Diet Rats
Authors: Courelli Asimina S. , Mazor Rafi , Schmid‐Schonbein Geert W.
Published: November 2023

The mechanisms for insulin resistance with type 2 diabetes have been studied extensively, but there is no generally accepted consensus about its etiology. In spontaneously hypertensive rats, we have shown that cleavage of the extracellular domain of the insulin receptors destroys its ability to signal after insulin binding, generating insulin resistance and reduced glucose uptake. Recent evidence suggests that insulin resistance in obese diabetic patients and in the spontaneously hypertensive rat is associated with increased proteolytic (e.g., MMP‐9 and elastase) activity in the blood. We hypothesized that rats given high fat diet (HFD) develop increased intestinal permeability allowing pancreatic trypsin to escape the intestinal lumen and cleave insulin receptors. We examined the insulin receptor and trypsin levels in the intestine, the liver, and the plasma in rats consuming normal diet (ND) and HFD. Immunohistochemistry (IHC) showed a decrease in submucosal and intestinal wall extracellular insulin receptor subunit IRa and an increase in submucosal and intestinal wall trypsin in HFD versus ND rats. In the liver, similar trends were observed, with increase in trypsin levels and decrease in IRa levels in HFD rats. Western blots of the blood plasma showed a marginal increase in plasma trypsin (p‐value=0.06) and IRa levels (p‐value=0.065) in HFD rats. The increase of trypsin in the intestine and liver of HFD rats suggests that a high fat diet alters intestinal permeability to allow digestive trypsin to escape out of the lumen into the blood stream, and cleave IRa in the intestinal wall and the liver.

Support or Funding Information

Supported by HL 10881.
Early Childhood Predictors of Life course BMI Latent Class Trajectories in a Guatemalan Cohort
Authors: Ford Nicole D. , Ramirez‐Zea Manuel , Martorell Reynaldo , Stein Aryeh D.
Published: November 2023

Objective

In recent years, Latin America has experienced dramatic increases in obesity. Programming to address under‐nutrition can also potentially affect obesity trends – especially among children outside the critical window of the first 1,000 days. We examined the role of early childhood factors on the timing and rate of body mass index (BMI) gain using latent class trajectories in a Guatemalan cohort.

Methods

Study participants (741 men, 711 women) were born in the El Progreso department of Guatemala from 1962–77 and have been followed prospectively since participating in a nutrition supplementation trial as children. Sex‐specific BMI latent class trajectories were derived from 22 possible measures of height and weight: 5 from 1–12 months; 3 from 13–23 months; 5 from 24–50 months; 3 from 51–84 months; 2 from 10–20y; and 4 from 21–42y. We estimated the role of the type of nutrition supplement (Atole vs. control beverage), timing of exposure (conception through age 2 y vs. other), and their interaction (using a difference‐in‐difference interaction test), and childhood household socioeconomic status (SES) on BMI latent class using multinomial logistic regression.

Results

We identified 3 BMI latent classes (low (39%), medium (46%), and high (14%)) in men and 2 classes (low (57%) and high (43%)) in women. Atole status and timing of exposure differed significantly by BMI latent class in both men (p<.01) and women (p<.0001). High SES tertile was associated with increased odds of high BMI latent class membership in both men (OR 2.07; 95% CI 1.19, 3.59) and women (OR 1.92; 95% CI 1.29, 2.84) relative to the lowest tertile. Among women, middle SES tertile was also associated with increased odds of high BMI latent class membership (OR 1.60; 95% CI 1.07, 2.38) relative to the lowest tertile. Exposure to Atole during the first 1,000 days was not significantly associated with BMI latent class membership (difference‐in‐difference test ‐ p>0.2 for men; p>0.6 for women).

Conclusion

Exposure to Atole during the first 1,000 days was not significantly associated with BMI latent class membership, suggesting that programs to improve nutritional status are unlikely to adversely affect BMI trajectories. Childhood household SES was associated with increased odds of high BMI latent class membership – the pathways through which this operates still need to be explored.

Support or Funding Information

Funding: This research was funded by the National Institutes of Health.
Protein intake, breastfeeding frequency and breastfeeding duration affect BMI from infancy to mid‐childhood
Authors: Wright Melecia , Sotres‐Alvarez Daniela , Mendez Michelle , Adair Linda
Published: November 2023

Background

Protein intake (PI) is an important determinant of growth, but excess protein in infancy has been associated with increased risk of obesity. Few studies have explored age‐specific associations of PI with BMI from infancy to adulthood.

Objective

To analyze how PI and breastfeeding relate to infant and toddler BMI, and how breastfeeding history and PI relate to BMI from age 2 to 22 yr using 24‐hour dietary recalls and anthropometric data from the Cebu Longitudinal Health and Nutrition birth cohort.

Methods

Random‐effects longitudinal regression models were used to estimate 1) the joint association of daily breastfeeding frequency (BF) and dietary protein residuals with concurrent BMI Z‐scores measured bi‐monthly from 2 to 24 months (n=2899), and 2) the association of breastfeeding history and protein residuals with concurrent BMI measured at ages 2, 11, 15, 19 and 22 years (n=2435). Where appropriate, models included statistical interactions (PI*energy, energy*age, BF*energy, BF*age), and were adjusted for socio‐demographic and anthropometric confounders (maternal education, maternal height and maternal age at baseline, offspring sex, birth weight and age‐2 BMI, and time‐varying household assets, urbanicity, offspring age and offspring education).

Results

1) Relative to not being breastfed the previous day, breastfeeding was associated with higher zBMI, though this effect ameliorated with time (Beta=0.524 at 6mo & 0.138 at 18mo). An additional 5 breast milk feedings in the previous day contributed to higher zBMI in younger infants (B=0.030 at 6mo) and lower zBMI in later infancy (B=−0.075 at 18mo). Compared to those at the 25th percentile of protein intake, being at the 75th percentile of protein intake was positively associated with zBMI regardless of age, however, the magnitudes of these associations were highest in non‐breastfed and older infants (at 6 mo: B=0.019 vs 0.005, at 18 mo: B=0.024 vs 0.012 for non‐breastfed vs breastfed infants respectively). 2) In post‐infancy analyses, 15 months of breastfeeding duration was inversely associated with BMI at age 11 (Beta=−0.145). Protein residuals were not significantly associated with BMI in the post‐infancy analyses. (All shown betas were statistically significant, p<0.05.)

Implications

Breastfeeding frequency, dietary protein intake and breastfeeding duration are significant contributors to concurrent BMI in infancy and childhood.

Support or Funding Information

Howard Hughes Medical Institute International Student Research Fellowship
Low Plasma Concentrations of High‐Density Lipoprotein Cholesterol (HDL‐C) Associated with Shorter Duration of Pregnancy: A Nested Cohort Study in Ghana
Authors: Oaks Brietta M , Stewart Christine P , Laugero Kevin D , Adu‐Afarwuah Seth , Lartey Anna , Vosti Stephen A , Ashorn Per , Dewey Kathryn G
Published: November 2023

Background

Recent studies have suggested that low serum cholesterol is associated with preterm birth (birth < 37 wk gestation), however results are mixed and research has been limited primarily to populations from high‐income countries.

Objective

To determine whether maternal blood lipid concentrations, at ≤ 20 wk or 36 wk gestation, are associated with duration of gestation.

Methods

We performed a nested cohort (n=320) study of pregnant Ghanaian women ≤ 20 wk gestation enrolled in a large randomized controlled trial. Total cholesterol, high density lipoprotein cholesterol (HDL‐C), low density lipoprotein cholesterol (LDL‐C), and triglycerides were analyzed in plasma samples, and gestational age was determined by ultrasound at baseline. A linear regression model examined the association between each blood lipid and duration of gestation. Blood lipids were examined both as continuous variables and categorically as low (<10th percentile), referent (10–90th percentile), and high (>90th percentile).

Results

At baseline, blood lipid concentrations were not associated with duration of gestation. At 36 wk gestation, higher HDL‐C was associated with a longer duration of gestation (β‐coefficient ± SE: 1.8 ± 0.7 days/mmol/L, p=0.02), independent of assigned group in trial, gestational age at enrollment, maternal baseline BMI, woman's age, parity, infant gender, asset index, season at enrollment, and time between sample collection and last meal. Among women with low HDL‐C at 36 wk gestation, duration of gestation was 5.9 days shorter when compared with the referent group (10–90th percentile) (p = 0.02) and 8.5 days shorter when compared with the high HDL‐C group (p = 0.003). LDL‐C was not significantly associated with duration of gestation at 36 wk gestation in linear regression analyses (adjusted β‐coefficient ± SE: −1.2 ± 0.7 days/mmol/L, p=0.08). Among women with low LDL‐C at 36 wk gestation, duration of gestation was 4.9 days longer when compared with the referent group (p = 0.051). Total cholesterol and triglycerides were not significantly associated with pregnancy duration.

Conclusion

Low HDL‐C in the third trimester of pregnancy is associated with a shorter duration of pregnancy in this study population of Ghanaian women.

Support or Funding Information

Bill & Melinda Gates Foundation.
Applied Anatomy of the Gastrocnemic Veins
Authors: Aragão José Aderval
Published: November 2023

The objective of present paper was to carry out an anatomic study of the gastrocnemic veins in adult human cadavers by dissection. This study was made with 20 human adult cadavers, all male, fixed and maintained in 10% formaldehyde solutions. Bodies presenting detectable macroscopic alterations, such as fracturations (broken bones) deformities, malformation and surgery done in the popliteal region were excluded from the observation. The dissection and observation of these veins was done without optical tools. All gastrocnemic veins were dissected from their emerging of the heads of the gastrocnemic muscle to the place of draining. In order to take the measurements, a digital pachymeter was used. Descriptive statistics were used for the variables of the study. In 80 gastrocnemic dissected muscle heads 438 gastrocnemic heads were found, 233 of which on the right peg and 205 on the left leg. 95 main trunks were identified, 51 of which on the right leg and 44 on the left leg. The average extension of these trunks was 2.17 cm on the right leg and 2.0 cm on the left leg. Of the total of the main gastrocnemic trunks, 83 end in the popliteal vein and 12 in other veins. In 30 gastrocnemic trunks of the right leg 32 valves were found and the lack of valves in 21. On the left leg 33 valves were found on 30 gastrocnemic trunks and the lack of valves on 14 trunks. Of the anatomic point of view, the gastrocnemic veins present an arrangement in form of a net. The right leg showed a major quantity of these veins than the left leg. The anatomic arrangement of these veins is rather complex and assumes the typical disposition of a net. Four different types of nets were described. The average length and number of valves of the gastrocnemic trunk were similar on both legs. Most of the gastrocnemic trunks emerge into the popliteal vein. The statistic treatment applied indicated that there is significance of the variation of extension of the main gastrocnemic veins, when considered by type of net and head of the gastrocnemic muscle.
Evaluating the Impact of Pre‐Matriculation Instruction on Academic Performance in the Anatomical and Physiological Sciences
Authors: Chico Diane E , Smith Sherry , Chen Wei‐Jung A , Peterson Thomas V , Hairrell Angela
Published: November 2023

The Texas A&M Health Science Center College of Medicine recently implemented a pre‐matriculation program (MedCamp) for a selected group of first year students. This study was conducted to correlate the MedCamp experience with academic performance in the first‐year biomedical science disciplines in gross anatomy, histology and physiology. The exam performance of students who participated in MedCamp (“MedCampers”) was compared with that of students who did not participate in MedCamp. The components of this 4‐week MedCamp included: providing a head‐start on acculturating to the medical community; taking select first‐year curriculum courses such as anatomy, histology, physiology, and molecular medicine (including quizzes and exams); experiencing simulated clinical encounters; developing professionalism skills; providing requisite academic support and tutoring; and having a current M2 student, a staff member, and a faculty member serve as mentors. All of these activities were geared toward preparing students for the rigor of the curriculum, social and professional expectations as medical students, and insight into areas for improvement. Twenty‐four students who met the selecting criteria for this program participated voluntarily in MedCamp. Students ranged in age from 21–51, with 10 females and 14 males that represented many ethnic groups, and had an average MCAT score of 29.17 and overall BCPM (biology, chemistry, physics, and math) GPA of 3.61. Data analysis is ongoing, but qualitative results were extremely positive from the participants, especially regarding social support needed for academic success. Preliminary quantitative analyses of written, laboratory practical, and overall exam performance indicated that the MedCampers performed well and did not show a significant difference in performance when compared with their peers (two tailed t‐tests, α=0.05). Our findings suggested that the MedCamp pre‐matriculation program was effective in preparing students who have been traditionally identified in the literature as having pre‐admission factors associated with difficulties in medical school. These findings align with findings of other pre‐matriculation programs in regard to medical school academic performance.

Support or Funding Information

The Minority Health Research and Education Grant Program (Higher Education Coordinating Board)
Repression but not deletion of β‐catenin contributes to heart failure
Authors: Kararigas Georgios , Zelarayan Laura C , Toischer Karl , Summer Holger , Baczko Istvan , Golz Stefan , Hasenfuss Gerd , Jarry Hubertus , Regitz‐Zagrosek Vera
Published: November 2023

The role of β‐catenin and the actions of 17β‐estradiol (E2) in cardiovascular (patho)physiology are not fully understood. We aimed at the characterization of the effects of the E2/β‐catenin axis in the healthy C57Bl/6N heart. Two‐month‐old female C57Bl/6N wild‐type (WT) and cardiac‐specific β‐catenin‐deleted (β‐catΔex2–6) mice were ovariectomized and randomized to an E2‐containing or soy‐free (control, CON) diet (n = 7–13/group). All mice underwent transthoracic two‐dimensional echocardiography under volatile anesthesia (isoflurane 2%) following established procedures. The three‐month physiological dose of E2 led to a significant repression of nuclear β‐catenin levels compared with CON (P < 0.001) in WT mice. This was underlain by a significant decrease in the heart‐weight‐to‐tibia‐length ratio and cardiomyocyte cross‐sectional area (E2 vs. CON WT mice P < 0.001). Furthermore, echocardiographic measurements revealed a significant decrease in septum width (P < 0.001), posterior wall thickness (P < 0.01) and fractional shortening (P < 0.05) in E2‐treated WT mice compared with CON. Deletion of β‐catenin abrogated these E2‐dependent detrimental effects on cardiac structure and function. Mechanistically, we found a significant increase in the levels of the ubiquitin ligase and key regulator of proteasome‐dependent protein degradation muscle‐specific RING finger protein 1 (MuRF1) by E2 compared with CON in WT mice (P < 0.05), while there was no significant effect in β‐catΔex2–6 mice. In a translational approach, we profiled the transcriptome of left ventricles of female patients (n = 5) with end‐stage non‐ischemic dilated cardiomyopathy (DCM) vs. women (n = 8) with no apparent cardiovascular disorder. We found a significant induction in the expression of the genes coding for SFRP5, a negative regulator of Wnt signaling, DACT2, an antagonist of beta‐catenin, and APC2, which is required for targeted degradation of beta‐catenin (P < 0.01), in DCM samples. Our mouse data indicate that repression of β‐catenin contributes to heart failure and our human data suggest that targeting Wnt/beta‐catenin signaling in heart failure may be of therapeutic value.

Support or Funding Information

DZHK (German Centre for Cardiovascular Research)
Student Approaches to Anatomy Learning are Influenced by Clinically Relevant Peer‐Peer Teaching
Authors: Lazarus Michelle , Dos Santos Jason , Haidet Paul , Whitcomb Tiffany
Published: November 2023

An anatomic translation of the clinical handoff was developed to facilitate peer‐peer teaching and to enhance integration of basic science anatomy with clinical medicine. The anatomic handoff's impact on the donor dissection environment was evaluated using a qualitative grounded theory analysis of student experiences (n = 32) and constant comparative method. Kappa analysis was used to evaluate agreement between givers’ and receivers’ Likert data which reported student perceptions of handoff usefulness and giver preparedness. Three themes emerged from students’ summaries of anatomic handoff experiences: “Learning by teaching”, “acquiescing to doing more with less”, and a “distrust of the peer handoff process”. Themes aligned with specific handoff roles (giver, receiver, or both); the giver role associated with the positive impact that teaching peers has on anatomy education, while the receiver role correlated negatively to the handoff experience because of a skepticism of peers’ abilities. All themes demonstrated that the anatomic handoff encouraged students’ focus on knowledge preparation and reflection outside of designated class time and provided an effective mechanism for promoting student focus on anatomical relationships, self‐directed learning, and condensation of complex material. Statistical analysis suggests that students’ perception of handoff usefulness correlates with allocation of time for these deeper learning strategies. Together these data suggest that a clinical framework within basic science coursework influences the anatomy learning environment, improves student desire for self‐directed learning, and provides opportunities for student's to practice essential clinical skills, suggesting that this approach may be useful to introduce clinical context into basic science learning.
Colonic Dysfunction Following Acute Spinal Cord Injury: Oxidative Damage to Interstitial Cells of Cajal?
Authors: White Amanda R , Holmes Gregory M
Published: November 2023

Over 250,000 Americans are spinal cord injured with approximately 12,000 new injuries occurring annually. Colonic dysregulation is widely acknowledged as a common co‐morbidity associated with spinal cord injury (SCI). SCI‐induced colonic dysregulation is recognized as a lifelong physical and psychological challenge for SCI patients and gravely impacts quality of life. The combined actions of the enteric nervous system (ENS) and interstitial cells of Cajal (ICC) contribute to slow‐wave propagation along much of the gastrointestinal (GI) tract including the colon. Mechanisms leading to colonic dysmotility following SCI remain largely understudied and, therefore, poorly understood, however, studies focusing on colitis, aging, and slow transit constipation suggest that ICCs are dramatically reduced and may reflect a similar mechanism of dysfunction following SCI.

Aim

We hypothesized that acute spinal cord injury results in colonic inflammation, elevated reactive oxygen species (ROS) thereby provoking a reduction of colonic ICCs.

Methods

Male Wistar rats received a contusion spinal cord injury at 3 days and 1 week prior to in vivo experimentation and tissue harvest for histological evaluation. In vivo colonic contractility was measured via a Mikro‐Tip® catheter pressure transducer that was intra‐luminally inserted within the descending colon. Whole tissue colonic samples from SCI or surgical controls were processed with DHE to visualize oxidative stress. In addition, c‐Kit immunofluorescence was performed to evaluate the colonic ICC populations within the myenteric plexus of both surgical control and SCI rats.

Results

Similar to previous reports of anorectal dysmotility, contraction within the descending colon were reduced following acute SCI. Preliminary data collected from DHE staining suggested an increase in ROS within the myenteric plexus of the SCI colon when compared to the surgical control. Immunofluorescent c‐Kit labeling displayed well‐structured and intact ICC networks throughout the myenteric plexus and circular muscle of the sham colon. Conversely, the 3 day SCI samples displayed ICC networks that appeared structurally normal but not completely intact and by 1 week the networks were disorganized and fragmented. With increased ROS and ICC networks progressively worsening over time, this data suggests possible prolonged inflammatory damage.

Conlusion

In the acute (3 day) phase of experimental SCI, diminished blood flow to the visceral tissues has been associated with increased inflammatory markers and vagally‐mediated dysmotility in the upper GI tract. Our preliminary data suggests that post‐SCI inflammation and oxidative stress may be prolonged and provoke diminished colonic motility, possibly through the disruption of intrinsic ICCs generating intrinsic pacemaker activity of smooth muscle.

Support or Funding Information

Support: NINDS #049177
Exosomes and their RNA contents as mediators of therapeutic regeneration
Authors: Marban Eduardo
Published: November 2023

The heart is a terminally‐differentiated organ with a low rate of cellular turnover. Patients who suffer a myocardial infarction (commonly known as a “heart attack”) can lose up to 40% of their functional heart muscle within hours, leaving them prone to death and disability. Once formed, scar does not resolve spontaneously, and, once lost, living heart muscle does not regrow on its own. We challenged that pessimistic dogma using a novel approach: growing regenerative cells from a patient's heart and transplanting those cells back into the zone of injury. In the first‐in‐human CADUCEUS trial, we used magnetic resonance imaging to quantify scar and living heart muscle before and after cardiosphere‐derived cell (CDC) therapy in patients who had suffered moderately large heart attacks. Control subjects randomized to receive standard care behaved according to dogma: scar did not shrink, and living heart muscle did not regrow, over the one‐year period of follow up. In contrast, patients who had received CDCs experienced reduction of scar by about half, and regrowth of substantial amounts (>20 g) of viable myocardium. CADUCEUS was the first controlled study to show evidence of therapeutic regeneration in humans (Lancet 379:895–904, 2012). We have since discovered that allogeneic CDCs are safe and effective in preclinical models, prompting initiation of the ongoing ALLogeneic heart STem cells to Achieve myocardial Regeneration (ALLSTAR) clinical trial. Current mechanistic studies focus on the role of exosomes, and their RNA contents, as mediators of the therapeutic benefits, and on macrophages as important effector cells.

Support or Funding Information

Funded by NIH and by the California Institute for Regenerative Medicine
O‐GlcNAc occurs cotranslationally to stabilize nascent polypeptides
Authors: Vocadlo David , Zhu Yanping , Liu Ta‐Wei , Cecioni Samy , Eskandari Raieh , Zandberg Wesley , Willems Lianne
Published: November 2023

Nucleocytoplasmic glycosylation of proteins with O‐linked N‐acetylglucosamine residues (O‐GlcNAc) is mediated by the glycosyltransferase O‐GlcNAc transferase (OGT). O‐GlcNAc is recognized as a common post‐translational modification and is found on hundreds of proteins within all metazoans studied to date. O‐GlcNAc has emerged as a regulator of diverse cellular processes ranging from gene expression through to circadian rhythm. Notably, impairments in cellular O‐GlcNAcylation have been found to lead to decreases in the levels of various proteins and this is one mechanism by which O‐GlcNAc seems to exert its varied physiological effects. Here we use a chemical biology approach in combination with biochemical fractionation to show that O‐GlcNAcylation also occurs on polypeptides that are emerging from the ribosome. Using both chemical and genetic blockade of OGT we show that this cotranslational O‐GlcNAcylation protects nascent polypeptide chains from premature degradation by decreasing their cotranslational ubiquitylation. Given that hundreds of proteins are O‐GlcNAcylated within cells, our findings suggest that cotranslational O‐GlcNAcylation may be a phenomenon regulating proteostasis of an array of nucleocytoplasmic proteins. We describe our recent findings and discuss the similarities between cotranslational O‐GlcNAcylation and the roles played by cotranslational N‐glycosylation occurring within the secretory pathway.

Support or Funding Information

Financial support through a Discovery Grant (Grant number: RGPIN/298406‐2010) the Natural Sciences and Engineering Research (NSERC) and the Canadian Institutes of Health Research (CIHR) (Grant number: MOP‐102756) is gratefully acknowledged. Y.Z. thanks the CIHR for support through a postdoctoral fellowship. D.J.V. acknowledges the kind support of the Canada Research Chairs program for a Tier I Canada Research Chair in Chemical Glycobiology and NSERC for support as an E.W.R. Steacie Memorial Fellow.
Dynamic Regulation Of The Signaling Lipid Phosphatidylinositol 3,5‐Bisphosphate
Authors: Weisman Lois S , Jin Natsuko
Published: November 2023

Cyclin dependent kinases (CDKs) are key regulators of the cell cycle, nutrient homeostasis, cell polarity and gene expression. Here we show an unexpected link between a CDK and the signaling lipid, phosphatidylinositol 3,5 bis phosphate (PI(3,5)P2). PI(3,5)P2 is required for the growth and development of fungi, plants and animals. Minor defects in the levels of this lipid underlie some neurological diseases. Moreover, PI(3,5)P2 plays essential roles in several organs. PI(3,5)P2 is generated by a protein complex that includes the PI3P‐5‐kinase Fab1 (called PIKfyve in mammals), the PI(3,5)P2 lipid phosphatase, Fig4, and the scaffold protein Vac14. PI(3,5)P2 levels are dynamic, and in response to selected signals transiently rise in both yeast and in cultured neurons. However, the upstream signaling pathways that regulate PI(3,5)P2 were unknown. We performed screens in yeast to determine upstream regulators of PI(3,5)P2. Here, we show that the yeast cyclin‐dependent kinase, Pho85 and the cyclin, Pho80 are required for the transient elevation of PI(3,5)P2. Pho85‐Pho80 directly phosphorylates Fab1 and positively regulates the synthesis of PI(3,5)P2. Furthermore, we find that Pho85‐Pho80 phosphorylation of Fab1 likely generates a conformation change that regulates Fab1. We found that in neurons, PIKfyve is a negative regulator of synaptic function. Notably, the mammalian homologue of Pho85‐Pho80, Cdk5‐ p35, is similarly a negative regulator of synaptic function. This raises the possibility that Cdk5 and PIKfyve could function in the same pathway. Indeed, we find that mammalian Cdk5‐p35 directly phosphorylates peptides of mammalian Fab1/PIKfyve, and is required for the synthesis of PI(3,5)P2 in mouse fibroblasts. These studies reveal a conserved, upstream regulator of Fab1/PIKfyve, and provide insights into how PI(3,5)P2 is regulated.

Support or Funding Information

Supported by R01 GM50403 and R01 NS064015 to LSW.
Redox modulation of curcumin stability: redox active antioxidants increase chemical stability and biological activity of curcumin
Authors: Zhang Guodong , Nimiya Yoshiki , Wang Weicang , Decker Eric
Published: November 2023

Substantial human and pre‐clinical studies have shown that curcumin, a dietary compound from turmeric, has beneficial effects on many human diseases. However, curcumin rapidly degrades at physiological pH, making it difficult to interpret the biological activities of curcumin and develop curcumin‐based therapeutics. Here we show that a series of redox active antioxidants with diverse chemical structures, including gallic acid, ascorbate (vitamin C), tert‐butylhydroquinone (TBHQ), caffeic acid, rosmarinic acid, and Trolox (a water‐soluble analog of vitamin E), dramatically increased curcumin stability in aqueous buffer and enhanced biological activity of curcumin in colon cancer cells. In addition, co‐administration of antioxidant significantly increased circulating level of curcumin in animal models. Together, these studies strongly suggest that a redox‐dependent mechanism plays a critical role in mediating curcumin degradation, and co‐administration of antioxidants could be a practical strategy to increase the chemical stability and biological activity of curcumin.
The Role of Grit in Body Weight Regulation over Time
Authors: Metzgar Catherine J , Nickols‐Richardson Sharon M
Published: November 2023

Management of body weight (BW) over time remains a challenge for most individuals, specifically women during young adulthood. Grit, the perseverance and passion for sustaining efforts to pursue goals over time, and other personality traits may play a role in BW regulation. This prospective study explored the association of grit, cognitive eating restraint (CER), disinhibition and hunger in predicting BW and BW change over 12 months in a sample of healthy premenopausal women. The Short Grit Scale (Grit‐S) and Eating Inventory (EI) were completed by 79 women [mean±SD, age: 31.5±8.2 y, BW: 76.3±19.2 kg, body mass index (BMI): 28.0±6.9 kg/m2] upon enrollment (baseline) and after completion of a 1‐year weight gain prevention intervention; BW and BMI were assessed at the same time intervals. Paired t‐tests were used to evaluate changes over time and independent t‐tests were used to compare women who met weight gain prevention criteria with those who did not. The relationship between baseline Grit‐S score and month 12 BW, BMI and percent BW change were examined using Pearson's correlation coefficients. Backward elimination regression was used to further evaluate predictors of month 12 BW, BMI and percent BW change. All analyses were conducted using SPSS (version 22.0); significance was set at P<0.05. Average Grit‐S, CER, disinhibition and hunger scores did not significantly change over 12 months. Body weight and BMI, respectively, at baseline and month 12 were negatively associated with baseline grit (baseline: r=−0.24, P<0.05; r=−0.23, P<0.05; month 12: r=−0.25, P<0.05; r=−0.23, P<0.05) and positively associated with disinhibition (baseline: r=0.31, P<0.01; r=0.29, P<0.01; month 12: r=0.34, P<0.01; r=0.31, P<0.01). Lower baseline disinhibition and greater increases in CER over time were related to successful weight gain prevention (both P<0.05). Change in BW was not associated with any measures. Disinhibition predicted month 12 BW (F=9.80, P<0.01) and BMI (F=8.08. P<0.01). No measures significantly predicted BW change. Successful body weight regulation over 12 months was characterized by low disinhibition at baseline and an increase in CER over time. Additionally, high levels of grit and low levels of disinhibition at baseline were related to lower BW and BMI at the end of the 1‐year intervention. Future interventions should consider strategies that manage disinhibition and increase CER over time.

Support or Funding Information

Funded by an Illinois Agricultural Experiment Station/National Institute of Food and Agriculture research grant (#1001251).
Dietary Small RNA Modulation of Gut Microbiota Composition: in‐silico and in‐vitro Analyses
Authors: Huang Haiqiu , Davis Cindy , Yu Liangli , Wang Thomas T. Y.
Published: November 2023

Small RNAs are ubiquitously found in plants, animals, and microorganisms. Recent research has indicated that exogenous small RNAs from plant sources might be able to survive the gastrointestinal tract and enter human circulation. The human gut microbiota, which forms the interface between diet and the human body, will be in direct contact with dietary small RNAs. Gut microbiota have been reported to play a pivotal role in pathology or prevention of chronic diseases, as well as in human development, physiology, immunity, and nutrition. However, the impact of dietary small RNAs on gut microbiota has never been reported. This study aimed to test the hypothesis that dietary small RNAs may modulate gut microbiota and therefore impact health outcomes. To begin to approach this complex problem, in‐silico/bioinformatic analysis was performed to elucidate potential bacterial targets for small RNAs. We identified several small RNAs abundant in corn (zma‐miR156a, −166a, and −168a), soy (gma‐miR156h, −168a, and −2118a) and tomato (sly‐miR164b and −168a) that may target critical bacterial genes, such as genes involved in cell growth (DNA polymerase, DNA replication inhibitor, transcriptional repressor), cell function (sodium/hydrogen exchanger, glycosyltransferase), and energy metabolism (long‐chain fatty acid‐CoA ligase, maltoporins). Modulation of these bacterial genes could potentially lead to changes in the composition and function of the gut microbiota. Using an in‐vitro fecal bacteria culture model under anaerobic condition, we found zma‐miR156a, a major corn small RNA, was stable for up to 6 hours with 80% recovery from culture media. Furthermore, using qPCR, we found one serving of fresh corn (164 g) contains about 4 μg of small RNAs. We also detected zma‐miR156a in commercial rodent chow (22 ng/g) and found that up to 5% of the ingested zma‐miR156a (24 hrs period) was detected in mouse fecal samples. Anaerobic culture of fecal bacteria in the presence of total small RNAs isolated from corn (25 μg/mL) did not affect total bacterial cell numbers, but did affect the bacterial composition. Corn small RNAs induced significant increases in Akkermansia (25%), Bacteroides (20%) and Firmicutes (413%). In summary, our in‐silico and in‐vitro analyses indicated a potential regulatory role of dietary small RNAs on gut microbiota composition. Further work is needed to determine if these changes in gut microbiota may influence health outcomes.
Mechanisms of appetite suppression after high intensity exercise in lean and obese boys
Authors: Hunschede Sascha , Schwartz Alexander , Kubant Ruslan , Akilen Rajadurai , Thomas Scott , Anderson G. Harvey
Published: November 2023

Background

High intensity exercise (HIE) suppresses appetite in adults and is thought to be mediated by appetite regulating hormones. It also affects a variety of other appetite controlling mechanism, such as inflammation and stress.

Rationale

Although the role of appetite hormones in HIE suppression of appetite has received much attention, their role remains unclear.

Hypothesis

HIE exercise induces a reduction of appetite due to an increase in inflammation and stress related responses.

Objective

To investigate and compare the underlying mechanisms contributing to the suppression of appetite with HIE in obese and lean children.

Methods

Crossover design of 11 lean and 11 obese boys (aged 10–18y) randomly assigned to rest or 30 min of HIE at 70% peak oxygen consumption (VO2peak). Subjective appetite was assessed before and after HIE with visual analog scales. Blood samples were collected at baseline (0 min), immediately after exercise at 50 min, 80 min and 110 min. Plasma biomarkers of appetite were measured by leptin, active ghrelin, glucagon‐like‐peptide‐1 (GLP‐1), peptide YY (PYY) and biomarkers of stress and inflammation were assessed by c‐reactive protein (CRP), Interleukin‐6 (IL‐6), tumor necrosis factor alpha (TNF‐α) and cortisol.

Results

At baseline, appetite was significantly increased (p=0.026) in obese compared to lean children. Appetite increased over time (p<0.001) but was suppressed by HIE (p=0.006) with no differences in lean and obese. Leptin (p<0.001), glucose (p=0.011) and insulin (p<0.001) were also increased more in obese children. At baseline there was no difference in active ghrelin, GLP‐1, PYY, CRP, IL‐6, TNF‐α and cortisol between lean and obese children. HIE suppressed active ghrelin (p<0.001) and increased inflammation as measured by interleukin‐6 (p<0.001), tumor‐necrosis‐factor‐alpha (p<0.001) and stress as measured by cortisol (p<0.001), with no differences in lean or obese. Blood glucose (p=0.002) and Insulin (p=0.028) increased with HIE. Interaction analysis for bodyweight and HIE revealed an increase in blood glucose (p=0.032) and insulin (p=0.042) in lean when compared to obese. The anorectic hormones, leptin, GLP‐1, PYY and CRP and biomarkers of inflammation and stress, CRP and cortisol, were not affected by HIE.

Conclusion

The suppression of appetite with HIE was similar in lean and obese boys and accompanied by a decrease of the orexigenic hormone active ghrelin and increased inflammation and stress responses. The relative role of each of these signals in the suppression of appetite with HIE remains to be determined.

Support or Funding Information

This project was funded by the Canadian Institutes of Health Research (CIHR).