Metabolic Regulation of Epithelial to Mesenchymal Transition: Implications for Endocrine Cancer

York University Librarie

Measuring Entrainment in Spontaneous Code-switched Speech

It is well-known that interlocutors who entrain to one another have more successful conversations than those who do not. Previous research has shown that interlocutors entrain on linguistic features in both written and spoken monolingual domains. More recent work on code-switched communication has also shown preliminary evidence of entrainment on certain aspects of code-switching (CSW). However, such studies of entrainment in code-switched domains have been extremely few and restricted to human-machine textual interactions. Our work studies code-switched spontaneous speech between humans by answering the following questions: 1) Do patterns of written and spoken entrainment in monolingual settings generalize to code-switched settings? 2) Do patterns of entrainment on code-switching in generated text generalize to spontaneous code-switched speech? We find evidence of affirmative answers to both of these questions, with important implications for the potentially "universal" nature of entrainment as a communication phenomenon, and potential applications in inclusive and interactive speech technology

A potent betulinic acid analogue ascertains an antagonistic mechanism between autophagy and proteasomal degradation pathway in HT-29 cells

Betulinic acid (BA), a member of pentacyclic triterpenes has shown important biological activities like anti-bacterial, anti-malarial, anti-inflammatory and most interestingly anticancer property. To overcome its poor aqueous solubility and low bioavailability, structural modifications of its functional groups are made to generate novel lead(s) having better efficacy and less toxicity than the parent compound. BA analogue, 2c was found most potent inhibitor of colon cancer cell line, HT-29 cells with IC50 value 14.9 μM which is significantly lower than standard drug 5-fluorouracil as well as parent compound, Betulinic acid. We have studied another mode of PCD, autophagy which is one of the important constituent of cellular catabolic system as well as we also studied proteasomal degradation pathway to investigate whole catabolic pathway after exploration of 2c on HT-29 cells. Mechanism of autophagic cell death was studied using fluorescent dye like acridine orange (AO) and monodansylcadaverin (MDC) staining by using fluorescence microscopy. Various autophagic protein expression levels were determined by Western Blotting, qRT-PCR and Immunostaining. Confocal Laser Scanning Microscopy (CLSM) was used to study the colocalization of various autophagic proteins. These were accompanied by formation of autophagic vacuoles as revealed by FACS and transmission electron microscopy (TEM). Proteasomal degradation pathway was studied by proteasome-Glo™ assay systems using luminometer.The formation of autophagic vacuoles in HT-29 cells after 2c treatment was determined by fluorescence staining – confirming the occurrence of autophagy. In addition, 2c was found to alter expression levels of different autophagic proteins like Beclin-1, Atg 5, Atg 7, Atg 5-Atg 12, LC3B and autophagic adapter protein, p62. Furthermore we found the formation of autophagolysosome by colocalization of LAMP-1 with LC3B, LC3B with Lysosome, p62 with lysosome. Finally, as proteasomal degradation pathway downregulated after 2c treatment colocalization of ubiquitin with lysosome and LC3B with p62 was studied to confirm that protein degradation in autophagy induced HT-29 cells follows autolysosomal pathway. In summary, betulinic acid analogue, 2c was able to induce autophagy in HT-29 cells and as proteasomal degradation pathway downregulated after 2c treatment so protein degradation in autophagy induced HT-29 cell

Metabolic Regulation by p107 (Rbl1) Influences Muscle Stem Cell Fate Decisions

Skeletal muscle has a remarkable property of effective muscle fiber regeneration that maintain their normal physiology due to the presence of the adult muscle stem cells known as the satellite cells (SCs). The role of SCs is crucial, as myofiber turnover is an ongoing process during the lifetime of an individual to maintain proper muscle tissue viability. However, muscle wasting found in diseases such as muscular dystrophy and disorders that occur during the ageing process are associated with impaired SC function. Indeed, these complications are linked to compromised SC fate decisions for activation, self-renewal and commitment to muscle progenitor cells (MPs), which are characterized by diminished numbers. Thus, understanding the control pathways that impact SC fates is essential to improve their integrity for health and to benefit muscle diseases and disorders. Central to sustaining different SC fates is the regulation of energy generation between glycolysis in the cytoplasm and oxidative phosphorylation (Oxphos) in the mitochondria. However, the mechanisms that connect these energy provisioning centers to control cell behaviour remain obscure. Herein, our results reveal a mechanism by which mitochondrial-localized transcriptional co-repressor p107 governs MP proliferative rate, under the control of NAD+/NADH ratio. We found p107 directly interacts at the mitochondrial DNA promoter repressing mitochondrial-encoded genes. This reduces the mitochondrial ATP generation capacity, by limiting the electron transport chain complex formation. Importantly, the amount of ATP generated by the mitochondrial function of p107 is directly associated to the cell cycle rate in vivo and in vitro. This is exemplified by absence of p107 that drastically increased cell cycle progression and MP proliferation capacity through enhancement of ATP generation. Oppositely, forced expression of p107 in the mitochondria blocked cell cycle progression in vitro as a consequence of dampened ATP generation. Notably, Sirt1, whose activity is dependent on the cytoplasmic by-product of glycolysis, NAD+, directly interacts with p107 impeding its mitochondrial localization and function. Deletion of Sirt1 increased p107 mitochondrial localization, decreased MP mitochondrial Oxphos generation concomitant with attenuated cell cycle progression. Increasing the activity of Sirt1 had the converse effect on p107 function. In addition, we also showed that p107 genetically deleted skeletal muscle contained significantly more quiescent SCs, indicative of a better self-renewal ability. As a first step to test the physiological role of p107 on SCs and MPs, we assessed exercise in humans. We found p107 protein levels were inversely correlated with enhanced mitochondrial Oxphos following endurance exercise in skeletal muscle that might also occur in SCs. These novel results establish a new paradigm to manipulate muscle stem cell fate decisions that are impaired in many diseases and disorders

Role of sex in immune response and epigenetic mechanisms

Abstract The functioning of the human immune system is highly dependent on the sex of the individual, which comes by virtue of sex chromosomes and hormonal differences. Epigenetic mechanisms such as X chromosome inactivation, mosaicism, skewing, and dimorphism in X chromosome genes and Y chromosome regulatory genes create a sex-based variance in the immune response between males and females. This leads to differential susceptibility in immune-related disorders like infections, autoimmunity, and malignancies. Various naturally available immunomodulators are also available which target immune pathways containing X chromosome genes