Biology subjects

Slater, S.

Publications and source records attributed to Slater, S..

4 recordsLinked to original sources

bioRxiv2024

Cancer Cachexia in STK11/LKB1-mutated NSCLC is Dependent on Tumor-secreted GDF15

Cachexia is a wasting syndrome comprised of adipose, muscle, and weight loss observed in cancer patients. Tumor loss-of-function mutations in STK11/LKB1, a regulator of the energy sensor AMP-activated protein kinase, induce cancer cachexia (CC) in preclinical models and are associated with cancer-related weight loss in NSCLC patients. Here we characterized the relevance of the NSCLC-associated cachexia factor growth differentiation factor 15 (GDF15) in several patient-derived and genetically engineered STK11/LKB1-mutant NSCLC cachexia lines. Both tumor mRNA expression and serum concentrations of tumor-derived GDF15 were significantly elevated in multiple mice transplanted with patient-derived STK11/LKB1-mutated NSCLC lines. GDF15 neutralizing antibody administered to mice transplanted with patient- or mouse-derived STK11/LKB1-mutated NSCLC lines suppressed cachexia-associated adipose loss, muscle atrophy, and changes in body weight. The silencing of GDF15 in multiple human NSCLC lines was also sufficient to eliminate in vivo circulating GDF15 levels and abrogate cachexia induction, suggesting that tumor and not host tissues represent a key source of GDF15 production in these cancer models. Finally, reconstitution of wild-type STK11/LKB1 in a human STK11/LKB1 loss-of-function NSCLC line that normally induces cachexia in vivo correlated with the absence of tumor-secreted GDF15 and rescue from the cachexia phenotype. The current data provide evidence for tumor-secreted GDF15 as a conduit and a therapeutic target through which NSCLCs with STK11/LKB1 loss-of-function mutations promote cachexia-associated wasting.

cancer biology↗

bioRxiv2023

Regulation of BACH1 by hemin improves cardiac function in a mouse model of myocardial infarction

AimsThe BTB and CNC homology 1 (BACH1) transcription factor is a repressor of heme oxygenase-1 (HMOX1), a pivotal enzyme involved in antioxidant response and iron recycling. Here we investigated whether pharmacological modulation of the BACH1 by hemin impacts on antioxidant responses and reparative angiogenesis in a mouse model of myocardial infarction (MI). Methods and resultsIn vitro studies on vascular cells showed hemin treatment downregulates BACH1 gene and protein expression and upregulates HMOX1. This axis was confirmed to be modulated in the murine infarcted heart, with BACH1 being upregulated, and HMOX1 downregulated compared to sham. Treatment with hemin every 3 days for 28 days post-MI significantly decreased BACH1 and increased HMOX1 protein expression, though no decrease in oxidative stress markers was detected. Hemin treated mice showed increases in both capillary and arteriole density, and reduced iron accumulation compared with controls. Furthermore, echocardiology measurements showed hemin treatment induced significant improvements in left ventricular wall thickness, and cardiac function as indicated by increased ejection fraction, fractional shortening, and stroke volume measurements. ConclusionHemin has therapeutic potential to improve revascularisation and cardiac function in the heart post-MI.

molecular biology↗

bioRxiv2020

Human saphenous vein provides a unique source of anti-calcific pericytes for prosthetic cardiac valve engineering

AimsTissue engineering seeks to improve the longevity of prosthetic heart valves, but the cell source of choice has yet to be determined. This study aimed to establish a mechanistic rationale supporting the suitability of human adventitial pericytes (APCs). Methods and ResultsAntigenically APCs were immunomagnetically sorted from saphenous vein leftovers of patients undergoing coronary artery surgery and antigenically characterized for purity. Unlike bone marrow-derived mesenchymal stromal cells (BM-MSCs), APCs were resistant to osteochondrogenic induction by high phosphate (HP), as assessed by cytochemistry and expression of osteogenic markers. MiR-132 is natively expressed by APCs, with copy numbers being enhanced by HP stimulation. In silico bioinformatic analysis, followed by luciferase assays in HEK293 cells and miR-132 titration using agomiR and antagomiR in APCs, demonstrated that several osteochondrogenic genes were negatively regulated by miR-132. Among these, the glycolytic marker GLUT1 was downregulated in HP-stimulated APCs. In contrast to BM-APCs, APCs showed no increase in glycolysis under HP. Interestingly, incubation with APC-derived conditioned medium conferred swine cardiac valves with resistance to osteogenic transformation by HP; whereas, conditioned media from miR-132-knocked-down APCs failed to prevent the expression of these markers. Finally, we demonstrated the feasibility of using APCs to engineer bovine pericardium patches. APCs proliferate in the patch and secrete factors able to attract aortic endothelial cells under HP. ConclusionsHuman APCs are resistant to calcification compared with BM-MSCs and convey the anti-calcific phenotype to heart valves through miR-132. These findings may open new important avenues for prosthetic valve cellularization.

cell biology↗

bioRxiv2020

Mineralized collagen scaffolds fabricated with amniotic membrane matrix increase osteogenesis under inflammatory conditions

Defects in craniofacial bones occur congenitally, after high-energy impacts, and during the course of treatment for stroke and cancer. These injuries are difficult to heal due to the overwhelming size of the injury area and the inflammatory environment surrounding the injury. Significant inflammatory response after injury may greatly inhibit regenerative healing. We have developed mineralized collagen scaffolds that can induce osteogenic differentiation and matrix biosynthesis in the absence of osteogenic media or supplemental proteins. The amniotic membrane is derived from placentas and has been recently investigated as an extracellular matrix to prevent chronic inflammation. Herein, we hypothesized that a mineralized collagen-amnion composite scaffold could increase osteogenic activity in the presence of inflammatory cytokines. We report mechanical properties of a mineralized collagen-amnion scaffold and investigated osteogenic differentiation and mineral deposition of porcine adipose derived stem cells within these scaffolds as a function of inflammatory challenge. Incorporation of amniotic membrane matrix promotes osteogenesis similarly to un-modified mineralized collagen scaffolds, and increases in mineralized collagen-amnion scaffolds under inflammatory challenge. Together, these findings suggest that a mineralized collagen-amnion scaffold may provide a beneficial environment to aid craniomaxillofacial bone repair, especially in the course of defects presenting significant inflammatory complications.

bioengineering↗