Cellular Health Research Articles

Cholesterol Metabolism in Cancer and Cell Death.

Significance: Cholesterol is a type of lipid that plays a crucial role in building and maintaining cell membranes, producing certain hormones, and aiding in digestion. The two main types of cholesterol are low-density lipoprotein and high-density lipoprotein, and maintaining a healthy balance between them is essential for cellular function and organism health. Recent Advances: Cholesterol metabolism is a complex and dynamic process that involves biosynthesis, uptake, efflux, transport, and esterification. Disruptions in cholesterol metabolism are implicated in all stages of cancer, contributing to drug resistance, immune evasion, and autophagy dysfunction. These disruptions have also been linked to various types of regulated cell death, such as apoptosis, anoikis, lysosome-dependent cell death, pyroptosis, NETosis, necroptosis, entosis, ferroptosis, alkaliptosis, immunogenic cell death, and paraptosis. Critical Issues: Understanding the complex interplay between cholesterol metabolism and cell death and their impact on cancer development and progression is still a significant challenge. In addition, there is currently a lack of reliable biomarkers that can accurately reflect cholesterol metabolism dysregulation in cancer. Future Directions: To develop more specific and effective cholesterol metabolism-targeted therapies, a better understanding of the mechanisms by which cholesterol metabolism dysregulation contributes to cell death and cancer progression is needed. In addition, improving the accuracy and reliability of biomarkers will be crucial for monitoring and diagnosing cholesterol-related cancer subtypes and evaluating the effectiveness of cholesterol metabolism-targeted therapies. These efforts will require ongoing research and collaboration among multidisciplinary teams of scientists and clinicians. Antioxid. Redox Signal. 39, 102-140.

Mitigating Oxidative Stress in Perinatal Cells: A Critical Step toward an Optimal Therapeutic Use in Regenerative Medicine.

Oxidative stress (OS) occurs when the production of reactive oxygen species (ROS) is not balanced by the body's antioxidant defense system. OS can profoundly affect cellular health and function. ROS can have a profound negative impact on cells that undergo a predestined and time-regulated process of proliferation or differentiation, such as perinatal stem cells. Due to the large-scale employment of these immunotolerant stem cells in regenerative medicine, it is important to reduce OS to prevent them from losing function and increase their application in the regenerative medicine field. This goal can be achieved through a variety of strategies, such as the use of antioxidants and other compounds that can indirectly modulate the antioxidant defense system by enhancing cellular stress response pathways, including autophagy and mitochondrial function, thereby reducing ROS levels. This review aims to summarize information regarding OS mechanisms in perinatal stem cells and possible strategies for reducing their deleterious effects.

The Interplay of Adipokines, Body Composition and Glucose Homeostasis in Pregnant Women with a History of RYGB Operation.

Roux-en-Y gastric bypass operations (RYGB-OP) and pregnancy alter glucose homeostasis and the adipokine profile. This study investigates the relationship between adipokines and glucose metabolism during pregnancy post-RYGB-OP. (1) Methods: This is a post hoc analysis of a prospective cohort study during pregnancy in 25 women with an RYGB-OP (RY), 19 women with obesity (OB), and 19 normal-weight (NW) controls. Bioimpedance analysis (BIA) was used for metabolic characterization. Plasma levels of adiponectin, leptin, fibroblast-growth-factor 21 (FGF21), adipocyte fatty acid binding protein (AFABP), afamin, and secretagogin were obtained. (2) Results: The phase angle (φ) was lower in RY compared to OB and NW. Compared to OB, RY, and NW had lower leptin and AFABP levels, and higher adiponectin levels. φ correlated positively with leptin in RY (R = 0.63, p < 0.05) and negatively with adiponectin in OB and NW (R = -0.69, R = -0.69, p < 0.05). In RY, the Matsuda index correlated positively with FGF21 (R = 0.55, p < 0.05) and negatively with leptin (R = -0.5, p < 0.05). In OB, FGF21 correlated negatively with the disposition index (R = -0.66, p < 0.05). (3) Conclusions: The leptin, adiponectin, and AFABP levels differ between RY, OB, and NW and correlate with glucose metabolism and body composition. Thus, adipokines might influence energy homeostasis and maintenance of cellular health during pregnancy.

Hsp90 mutants with distinct defects provide novel insights into cochaperone regulation of the folding cycle.

Molecular chaperones play a key role in maintaining proteostasis and cellular health. The abundant, essential, cytosolic Hsp90 (Heat shock protein, 90 kDa) facilitates the folding and activation of hundreds of newly synthesized or misfolded client proteins in an ATP-dependent folding pathway. In a simplified model, Hsp70 first helps load client onto Hsp90, ATP binding results in conformational changes in Hsp90 that result in the closed complex, and then less defined events result in nucleotide hydrolysis, client release and return to the open state. Cochaperones bind and assist Hsp90 during this process. We previously identified a series of yeast Hsp90 mutants that appear to disrupt either the 'loading', 'closing' or 'reopening' events, and showed that the mutants had differing effects on activity of some clients. Here we used those mutants to dissect Hsp90 and cochaperone interactions. Overexpression or deletion of HCH1 had dramatically opposing effects on the growth of cells expressing different mutants, with a phenotypic shift coinciding with formation of the closed conformation. Hch1 appears to destabilize Hsp90-nucleotide interaction, hindering formation of the closed conformation, whereas Cpr6 counters the effects of Hch1 by stabilizing the closed conformation. Hch1 and the homologous Aha1 share some functions, but the role of Hch1 in inhibiting progression through the early stages of the folding cycle is unique. Sensitivity to the Hsp90 inhibitor NVP-AUY922 also correlates with the conformational cycle, with mutants defective in the loading phase being most sensitive and those defective in the reopening phase being most resistant to the drug. Overall, our results indicate that the timing of transition into and out of the closed conformation is tightly regulated by cochaperones. Further analysis will help elucidate additional steps required for progression through the Hsp90 folding cycle and may lead to new strategies for modulating Hsp90 function.

The Drosophila gene encoding JIG protein (CG14850) is critical for CrebA nuclear trafficking during development.

Coordination of mitochondrial and nuclear processes is key to the cellular health; however, very little is known about the molecular mechanisms regulating nuclear-mitochondrial crosstalk. Here, we report a novel molecular mechanism controlling the shuttling of CREB (cAMP response element-binding protein) protein complex between mitochondria and nucleoplasm. We show that a previously unknown protein, herein termed as Jig, functions as a tissue-specific and developmental timing-specific coregulator in the CREB pathway. Our results demonstrate that Jig shuttles between mitochondria and nucleoplasm, interacts with CrebA protein and controls its delivery to the nucleus, thus triggering CREB-dependent transcription in nuclear chromatin and mitochondria. Ablating the expression of Jig prevents CrebA from localizing to the nucleoplasm, affecting mitochondrial functioning and morphology and leads to Drosophila developmental arrest at the early third instar larval stage. Together, these results implicate Jig as an essential mediator of nuclear and mitochondrial processes. We also found that Jig belongs to a family of nine similar proteins, each of which has its own tissue- and time-specific expression profile. Thus, our results are the first to describe the molecular mechanism regulating nuclear and mitochondrial processes in a tissue- and time-specific manner.

Efficacy of mesenchymal stem cell-delivery using perpendicular multi-needle injections to the skin: Evaluation of post-ejection cellular health and dermal delivery.

Mesenchymal stem cell (MSC)-therapy is increasingly being evaluated in clinical trials. Dermal delivery is not only time consuming but also unreliable, potentially hampering the therapeutic result. Therefore, qualification of cell delivery protocols is essential. This study evaluated a clinically relevant automated multi-needle injection method for cutaneous MSC-therapy, allowing the skin to be readily and timely treated, by assessing both the cellular health post-ejection and dermal delivery. Following dispensation through the injector (31G needles: 9- or 5-pin) the cellular health and potency (perceived- and long-term (12h) viability, recovery, metabolism, adherence, proliferation and IDO1-expression) of adipose-derived stem cells (10-20-50×106 cells/ml) were assessed in vitro in addition to dermal delivery of solution in human skin. No significant detrimental effect on the perceived cell viability, recovery, metabolism, adherence or IDO1-expression of either cell concentration was observed. However, the overall long-term viability and proliferation decreased significantly regardless of cell concentration, nonetheless marginally. An injection depth above 1.0mm resulted in all needles piercing the skin with dermal delivery from up to 89% needles and minimal reflux to the skin surface, and the results were confirmed by ultrasound and histology. The automated injector is capable of delivering dermal cell-doses with an acceptable cell quality.

Cytoprotective Properties of Citronella Oil (Cymbopogon nardus (L.) Rendl.) and Lemongrass Oil (Cymbopogon citratus (DC.) Stapf) through Attenuation of Senescent-Induced Chemotherapeutic Agent Doxorubicin on Vero and NIH-3T3 Cells.

This study aimed to determine the cytoprotective potentials of citronella (Cymbopogon nardus (L.) Rendl.) essential oil (CO) and lemongrass (Cymbopogon citratus (DC.) Stapf) essential oil (LO). The essential oils from citronella and lemongrass were obtained by steam-water distillation, then analyzed using Gas Chromatography-Mass Spectrophotometry (GC-MS) to determine the chemical constituents. The antioxidant activity of CO and LO was compared using a total antioxidant capacity kit. The viability of normal kidney epithelial cells Vero and fibroblast NIH-3T3 as the cell models were tested using a trypan blue exclusion assay. The effect of cellular senescence inhibition on both cell models was measured using senescence-associated β-galactosidase (SA-β-gal) staining. The mechanism of action of CO and LO in the protection of cellular damage against doxorubicin was also confirmed through 2',7'-dichlorofluorescin diacetate (DCFDA) staining to discover the ability to decrease reactive oxygen species (ROS) levels and a gelatin zymography assay to observe the activity of matrix metalloproteinases (MMPs). The major marker components of CO and LO were citronellal and citral, respectively. Both oils showed low cytotoxic activity against Vero and NIH-3T3 cells, with IC50 values of over 40 µg/mL. LO exhibited higher antioxidant capacity than CO, but there was no effect on the intracellular ROS level of both oils on Vero and NIH-3T3 cells. However, CO and LO decreased cellular senescence induced by doxorubicin exposure on both cells, as well as suppressed MMP-2 expression. Conclusion: Both CO and LO decrease the cellular senescence and MMP-2 expression with less cytotoxic effects on normal cells independently from their antioxidant capacities. The results were expected to support the use of CO and LO as tissue protective and anti-aging agents in maintaining the body's cellular health against chemotherapeutics or cellular damaging agents.

Triplet-Net Classification of Contiguous Stem Cell Microscopy Images.

Cellular microscopy imaging is a common form of data acquisition for biological experimentation. Observation of gray-level morphological features allows for the inference of useful biological information such as cellular health and growth status. Cellular colonies can contain multiple cell types, making colony level classification very difficult. Additionally, cell types growing in a hierarchical, downstream fashion, can often look visually similar, although biologically distinct. In this paper, it is determined empirically that traditional deep Convolutional Neural Networks (CNN) and classical object recognition techniques are not sufficient to distinguish between these subtle visual differences, resulting in misclassifications. Instead, Triplet-net CNN learning is employed in a hierarchical classification scheme to improve the ability of the model to discern distinct, fine-grain features of two commonly confused morphological image-patch classes, namely Dense and Spread colonies. The Triplet-net method improves classification accuracy over a four-class deep neural network by ∼ 3 %, a value that was determined to be statistically significant, as well as existing state-of-the-art image patch classification approaches and standard template matching. These findings allow for the accurate classification of multi-class cell colonies with contiguous boundaries, and increased reliability and efficiency of automated, high-throughput experimental quantification using non-invasive microscopy.

Abstract 232: Searching for Novel Regulators of the Mevalonate Pathway

The mevalonate pathway is an important metabolic pathway that provides cells with vital bioactive molecules. The pathway converts mevalonate into various sterol and nonsterol isoprenoids required for cellular maintenance and health, including, cholesterol, ubiquinione, dolichol, heme A, farnesyl, and gernaylgeranyl protein anchors. However, these molecules are energetically expensive to synthesize and toxic in excess, so tight regulation of the pathway is necessary at multiple steps. In order to identify novel proteins that help regulate the mevalonate pathway, we performed unbiased proteomic screens to detect protein-protein interactions in Huh7 cells, a human hepatocellular carcinoma cell line. Proximity labeling with a promiscuous biotin ligase (BioID), and affinity purification were performed using multiple enzymes from the pathway as bait (MVK, MVD, FDFT1, FDPS, SQLE, and LSS). Several proteins were detected using both techniques at statistically significant levels compared to control. An extensive literature review revealed that two hits, NAB1 (NGFI-A-binding protein 1) and KHDRBS1 (KH RNA Binding Domain Containing, Signal Transduction Associated 1), could have relevant and understudied interactions with mevalonate kinase (MVK). Therefore, to determine if NAB1 or KHDRBS1 regulate MVK, they were independently knocked down using siRNAs in vitro . Knockdown of NAB1 led to decreased mRNA expression and protein levels of MVK under sterol depleted conditions, and decreased expression of high-density lipoprotein (HDL) associated genes ( ABCA1 , ApoA1 , etc). Conversely, when MVK was knocked down under sterol replete conditions, NAB1 protein levels were similarly reduced. Thus, these two proteins undergo a previously unknown interaction which warrants further study. NAB1-MVK interaction might help explain the association between MVK single nucleotide polymorphisms (SNP) and circulating HDL levels in humans, and the increase of circulating HDL in NAB1 knock out (KO) mice.

Exosome-based malaria vaccine, a miracle of nanomedicine

Exosomes are the nano-size subpopulation of extracellular vesicles secreted by all living cells and they originated from the endosomes. In general, it is involved in Inter-Cellular communication. Exosomes transport several bioactive molecules (DNA, RNA, protein, etc.) from parental cells to recipient cells. This event showcases cellular health or pathologic status1. The invention of the exosome adds a new chapter in nanomedicine. After the event now nanomedicine overcome several limitations (toxicity, immune rejection, biocompatibility, stability, and target-specific drug transport). The current decade of scientific investigation suggests that exosomes have active participation in host-pathogen intercellular communication in several parasitic infected diseases including malaria2. Malaria is a lethal parasitic infectious disease that led to large population death globally. It is spared in the human host after biting of parasite load female anopheles bite. This parasitic development happens in a circulating system with red bold cells and this maturation face boosts of exosome secretion3. In Malaria ABCA1 (ATP-binding-cassette transporter 1) gene is most vital for exosome biogenesis and maintaining host-pathogen communication4. Experimental data shows that the ABCA1 gene knockout reduces the chance of cerebral Malaria5. In disease progression phage host-pathogen cell-to-cell interaction happens via exosome cargos miRNA and proteins, Both ingredients of exosome efficiently regulate genetic expression. Malaria-infected cells derived exosomes carry miRNA451a which is related to red blood cells (RBC) maturation and related to vascular permeability. Malaria derives exosome-associated noncoding RNA, and fragments of genomic DNA of Plasmodium involved in suppressing the innate immune cells activity6. The immune system suppresses during malaria, and infected RBCs derive exosome (Fig. 1) downregulation natural killer cell activity against parasites. Infected RBCs-derived exosome protein and inflammatory molecules suppress the immune system. During malaria, exosomes play a vital role in reducing T-cell proliferation and downregulating T-cell–mediated immune response7. The vaccine development for Malaria is most challenging because of the complex life cycle of Plasmodium and surface protein diversity, although some limited success stories there8. At the current time, large-scale malaria vaccine development and delivery focus on exosomes9. Exosome-based plasmid delivery plays the role in anti-malaria antigenic immune memory development and promotes humoral immunity10. In malarial, exosome is the most promising drug resistance overcoming tool. Although exosome-based vaccine needs more clinical investigation, it is the most efficient, has less immunogenic rejection, and it is capable across biological braise. The infected RBC derives exosome-related miRNA is the most exciting part of the malaria Vaccine research but it required deep investigation before being used. Infected RBC derives exosome-related mediated host immune system reprogramming is still unexplored side of the exosome-based malaria research domain. Detailed investigation is needed regarding host cells derived exosome cargos (inflammatory molecules, miRNAs) and malaria development multiple stages associate exosome heterogeneity11 to develop exosome base efficient malaria vaccine. Now the question comes about why malaria research focuses on exosomes? The exosome-based malarial treatment approach is innovative because it supports early diagnosis and therapeutic aspects it is more promising with null toxicity with less immune rejection, compare with the other approaches, exosomes have some advantages such as boosting the immune system against malaria, surface engineering exosomes are more efficient compared with other (liposome) approaches in drug delivery in the case of malaria. Exosome is a smart tool for malarial drug delivery because they provide better stability of the drug in the biological system and help them cross the biological barriers. The feasible aspect of exosome-based malaria research depends on the expertise in exosome research. It is possible if we develop an expert group and some of the exosome-related advanced equipment. Once this facility is established and maintained by a trained expert, that reduces the production cost of the downstream product. Exosome-based malarial treatment research adds a new chapter to parasitology research. Exosome helps to decode the malaria-associated pathological complication at the more detailed molecular level. We hope, this innovative approach will save large-scale populations from malaria globally.Figure 1: Exosome and malaria. (A) Infected red blood cells (RBCs) derive exosomes that inhibit RBCs development and suppression of immune response against malaria. (B) Exosome surface modification, drug delivery an innovative approach in exosome associate malaria vaccine development.Ethical approval and consent of publication None. Sources of funding None. Author contribution D.M. and R.D. has conceptualized the project. D.M., S.G., R.M., P.S.G., and A.A. have written the manuscript. A.D. and S.K.J. has guided the project. All authors have done the editing. All authors have contributed significantly in preparation of the manuscript. Conflict of interest disclosure The authors declare that they have no financial conflict of interest with regard to the content of this report. Research registration unique identifying number (UIN) Not Applicable. Guarantor All Authors. Availability of data and materials None.

Examining Sporadic Cancer Mutations Uncovers a Set of Genes Involved in Mitochondrial Maintenance.

Mitochondria are key organelles for cellular health and metabolism and the activation of programmed cell death processes. Although pathways for regulating and re-establishing mitochondrial homeostasis have been identified over the past twenty years, the consequences of disrupting genes that regulate other cellular processes, such as division and proliferation, on affecting mitochondrial function remain unclear. In this study, we leveraged insights about increased sensitivity to mitochondrial damage in certain cancers, or genes that are frequently mutated in multiple cancer types, to compile a list of candidates for study. RNAi was used to disrupt orthologous genes in the model organism Caenorhabditis elegans, and a series of assays were used to evaluate these genes' importance for mitochondrial health. Iterative screening of ~1000 genes yielded a set of 139 genes predicted to play roles in mitochondrial maintenance or function. Bioinformatic analyses indicated that these genes are statistically interrelated. Functional validation of a sample of genes from this set indicated that disruption of each gene caused at least one phenotype consistent with mitochondrial dysfunction, including increased fragmentation of the mitochondrial network, abnormal steady-state levels of NADH or ROS, or altered oxygen consumption. Interestingly, RNAi-mediated knockdown of these genes often also exacerbated α-synuclein aggregation in a C. elegans model of Parkinson's disease. Additionally, human orthologs of the gene set showed enrichment for roles in human disorders. This gene set provides a foundation for identifying new mechanisms that support mitochondrial and cellular homeostasis.

A novel near-infrared fluorescent probe with hemicyanine scaffold for sensitive mitochondrial pH detection and mitophagy study

Mitochondria, as an energy-producing powerhouse in live cells, is considered to be directly linked to cellular health. However, dysfunctional mitochondria and abnormal mitochondria pH would possibly activate mitophagy, cell apoptosis and intercellular acidification process. In this work, we synthesized a novel near infrared fluorescent probe (FNIR-pH) for measurement of mitochondrial pH based on the hemicyanine skeleton as a fluorophore. The FNIR-pH probe functioned as a mitochondrial pH substrate and exhibited quick and sensitive turn-on fluorescence responses to mitochondrial pH in basic solution due to the deprotonation of hydroxy group in the structure. From pH 3.0 to 10.0, the FNIR-pH exhibited almost 100-fold increase in fluorescence intensity at 766 nm wavelength. The FNIR-pH also displayed superior selectivity to various metal ions, excellent photostability, and low cytotoxicity, which facilitated further biological application. Owing to the proper pKa value of 7.2, the FNIR-pH paved the way for real-time monitoring of mitochondria pH changes in live cells and sensitive sensing of mitophagy. Moreover, the FNIR-pH probe was also implemented for fluorescent imaging of tumor-bearing mice to validate its potential application for in vivo imaging of bioanalytes and biomarkers.

Multifaceted mitochondria: moving mitochondrial science beyond function and dysfunction.

Mitochondria have cell-type specific phenotypes, perform dozens of interconnected functions and undergo dynamic and often reversible physiological recalibrations. Given their multifunctional and malleable nature, the frequently used terms 'mitochondrial function' and 'mitochondrial dysfunction' are misleading misnomers that fail to capture the complexity of mitochondrial biology. To increase the conceptual and experimental specificity in mitochondrial science, we propose a terminology system that distinguishes between (1) cell-dependent properties, (2) molecular features, (3) activities, (4) functions and (5) behaviours. A hierarchical terminology system that accurately captures the multifaceted nature of mitochondria will achieve three important outcomes. It will convey a more holistic picture of mitochondria as we teach the next generations of mitochondrial biologists, maximize progress in the rapidly expanding field of mitochondrial science, and also facilitate synergy with other disciplines. Improving specificity in the language around mitochondrial science is a step towards refining our understanding of the mechanisms by which this unique family of organelles contributes to cellular and organismal health.

The Ubiquitin-like Proteins of Saccharomyces cerevisiae.

In this review, we present a comprehensive list of the ubiquitin-like modifiers (Ubls) of Saccharomyces cerevisiae, a common model organism used to study fundamental cellular processes that are conserved in complex multicellular organisms, such as humans. Ubls are a family of proteins that share structural relationships with ubiquitin, and which modify target proteins and lipids. These modifiers are processed, activated and conjugated to substrates by cognate enzymatic cascades. The attachment of substrates to Ubls alters the various properties of these substrates, such as function, interaction with the environment or turnover, and accordingly regulate key cellular processes, including DNA damage, cell cycle progression, metabolism, stress response, cellular differentiation, and protein homeostasis. Thus, it is not surprising that Ubls serve as tools to study the underlying mechanism involved in cellular health. We summarize current knowledge on the activity and mechanism of action of the S. cerevisiae Rub1, Smt3, Atg8, Atg12, Urm1 and Hub1 modifiers, all of which are highly conserved in organisms from yeast to humans.

Morphological profiling by high-throughput single-cell biophysical fractometry

Complex and irregular cell architecture is known to statistically exhibit fractal geometry, i.e., a pattern resembles a smaller part of itself. Although fractal variations in cells are proven to be closely associated with the disease-related phenotypes that are otherwise obscured in the standard cell-based assays, fractal analysis with single-cell precision remains largely unexplored. To close this gap, here we develop an image-based approach that quantifies a multitude of single-cell biophysical fractal-related properties at subcellular resolution. Taking together with its high-throughput single-cell imaging performance (~10,000 cells/sec), this technique, termed single-cell biophysical fractometry, offers sufficient statistical power for delineating the cellular heterogeneity, in the context of lung-cancer cell subtype classification, drug response assays and cell-cycle progression tracking. Further correlative fractal analysis shows that single-cell biophysical fractometry can enrich the standard morphological profiling depth and spearhead systematic fractal analysis of how cell morphology encodes cellular health and pathological conditions.

Nuclear and cytoplasmic spatial protein quality control is coordinated by nuclear-vacuolar junctions and perinuclear ESCRT.

Effective protein quality control (PQC), essential for cellular health, relies on spatial sequestration of misfolded proteins into defined inclusions. Here we reveal the coordination of nuclear and cytoplasmic spatial PQC. Cytoplasmic misfolded proteins concentrate in a cytoplasmic juxtanuclear quality control compartment, while nuclear misfolded proteins sequester into an intranuclear quality control compartment (INQ). Particle tracking reveals that INQ and the juxtanuclear quality control compartment converge to face each other across the nuclear envelope at a site proximal to the nuclear-vacuolar junction marked by perinuclear ESCRT-II/III protein Chm7. Strikingly, convergence at nuclear-vacuolar junction contacts facilitates VPS4-dependent vacuolar clearance of misfolded cytoplasmic and nuclear proteins, the latter entailing extrusion of nuclear INQ into the vacuole. Finding that nuclear-vacuolar contact sites are cellular hubs of spatial PQC to facilitate vacuolar clearance of nuclear and cytoplasmic inclusions highlights the role of cellular architecture in proteostasis maintenance.

A novel ubiquitin-proteasome system regulation of Sgf73/ataxin-7 that maintains the integrity of the coactivator SAGA in orchestrating transcription.

Ataxin-7 maintains the integrity of Spt-Ada-Gcn5-Acetyltransferase (SAGA), an evolutionarily conserved coactivator in stimulating preinitiation complex (PIC) formation for transcription initiation, and thus, its upregulation or downregulation is associated with various diseases. However, it remains unknown how ataxin-7 is regulated that could provide new insights into disease pathogenesis and therapeutic interventions. Here, we show that ataxin-7's yeast homologue, Sgf73, undergoes ubiquitylation and proteasomal degradation. Impairment of such regulation increases Sgf73's abundance, which enhances recruitment of TATA box-binding protein (TBP) (that nucleates PIC formation) to the promoter but impairs transcription elongation. Further, decreased Sgf73 level reduces PIC formation and transcription. Thus, Sgf73 is fine-tuned by ubiquitin-proteasome system (UPS) in orchestrating transcription. Likewise, ataxin-7 undergoes ubiquitylation and proteasomal degradation, alteration of which changes ataxin-7's abundance that is associated with altered transcription and cellular pathologies/diseases. Collectively, our results unveil a novel UPS regulation of Sgf73/ataxin-7 for normal cellular health and implicate alteration of such regulation in diseases.

Structural basis of impaired disaggregase function in the oxidation-sensitive SKD3 mutant causing 3-methylglutaconic aciduria

Mitochondria are critical to cellular and organismal health. To prevent damage, mitochondria have evolved protein quality control machines to survey and maintain the mitochondrial proteome. SKD3, also known as CLPB, is a ring-forming, ATP-fueled protein disaggregase essential for preserving mitochondrial integrity and structure. SKD3 deficiency causes 3-methylglutaconic aciduria type VII (MGCA7) and early death in infants, while mutations in the ATPase domain impair protein disaggregation with the observed loss-of-function correlating with disease severity. How mutations in the non-catalytic N-domain cause disease is unknown. Here, we show that the disease-associated N-domain mutation, Y272C, forms an intramolecular disulfide bond with Cys267 and severely impairs SKD3Y272C function under oxidizing conditions and in living cells. While Cys267 and Tyr272 are found in all SKD3 isoforms, isoform-1 features an additional α-helix that may compete with substrate-binding as suggested by crystal structure analyses and in silico modeling, underscoring the importance of the N-domain to SKD3 function.

Structured dynamics of the cell-cycle at multiple scales

The eukaryotic cell cycle comprises 4 phases (G1, S, G2, and M) and is an essential component of cellular health, allowing the cell to repair damaged DNA prior to division. Facilitating this processes, p53 is activated by DNA-damage and arrests the cell cycle to allow for the repair of this damage, while mutations in the p53 gene frequently occur in cancer. As such, this process occurs on the cell-scale but affects the organism on the cell population-scale. Here, we present two models of cell cycle progression: The first of these is concerned with the cell-scale process of cell cycle progression and the temporal biochemical processes, driven by cyclins and underlying progression from one phase to the next. The second of these models concerns the cell population-scale process of cell-cycle progression and its arrest under the influence of DNA-damage and p53-activation. Both systems take advantage of structural modeling conventions to develop novels methods for describing and exploring cell-cycle dynamics on these two divergent scales. The cell-scale model represents the accumulations of cyclins across an internal cell space and demonstrates that such a formalism gives rise to a biological clock system, with definite periodicity. The cell population-scale model allows for the exploration of interactions between various regulating proteins and the DNA-damage state of the system and quantitatively demonstrates the structural dynamics which allow p53 to regulate the G2- to M-phase transition and to prevent the mitosis of genetically damaged cells. A divergent periodicity and clear distribution of transition times is observed, as compared with the single-cell system. Comparison to a system with a reduced genetic repair rate shows a greater delay in cell cycle progression and an increased accumulation of cell in the G2-phase, as a result of the p53 biochemical feedback mechanism.

The application of social cognitive theory (SCT) to the mHealth diabetes physical activity (PA) app to control blood sugar levels of type 2 diabetes mellitus (T2DM) patients in Takalar regency.

Background: People with Diabetes Mellitus (DM) experience an increased health risk due to reduced physical activities. Cellular health technology (mHealth) offers a way that people with DM can engage in more complex physical activities. Social Cognitive Theory (SCT) is the most commonly used theory in increasing physical activities. This study aims to find out the application of SCT in mHealth app to control blood sugar (GDP, HbA1C) of T2DM patients. Design and Method: This present study used a mixed method sequential explanatory design related to the application of mHealth Diabetes Physical Activity in Takalar Regency. The first step was to use qualitative methods with rapid assessment procedures in developing the application of SCT in mHealth. The second step was to validate and test the app through usability testing. The last step was intervening the development of mHealth app using quasi-experimental designs related to the influence of mHealth Diabetes Physical activity interventions in controlling blood sugar (GDP, HbA1c) in T2DM patients. The first group was the mHealth diabetes Physical activity (PA) intervention group; the second intervention group was a group monitored through Whatsapp group; and the third group was the group with physical activity module but without monitoring. Expected outcome: The findings of this study are expected to be the basis of evidence for nurses holding DM programs to make relevant policies and design an app-based physical activity promotion programs for T2DM patients. Conclusion: This protocol qualifies to be the basis of evidence for nurses holding Diabetes Mellitus programs in improving health services through IT-based health promotion programs.