The Role of Sirtuin-1 Isoforms in Regulating Mitochondrial Function.

The sirtuin-1 (SIRT1) gene contains multiple exons that usually undergo alternative splicing. The exclusion of one or more exons causes domain loss in the alternatively spliced isoforms and may change their functions. However, it is not completely established to what extent the loss of a non-catalytic domain could affect its regulatory function. Using muscle cells and SIRT1-knockout cells, we examined the function of the constitutively spliced isoform (SIRT1-v1) versus the alternatively spliced isoforms SIRT1-v2 and SIRT1-v3 that had lost part of the N-terminal region. Our data indicate that partial loss of the N-terminal domains in SIRT1-v2 and SIRT1-v3 attenuated their function. The full-length SIRT1-v1 significantly increased the oxidative phosphorylation and ATP production rate. Furthermore, SIRT1-v1 specifically upregulated the mitochondrial respiratory complex I without affecting the activity of complexes II, III, and IV. Additionally, domain loss affected the regulation of site-specific lysine acetylation in the histone H4 protein, the gene expression of respiratory complex I subunits, and the metabolic balance of oxidative phosphorylation versus glycolysis. Since alternatively spliced isoforms tend to increase with advancing age, the impact of SIRT1 isoforms on mitochondrial respiratory complexes warrants further investigation.

Valine improves mitochondrial function and protects against oxidative stress.

Among the branched-chain amino acids, leucine and isoleucine have been well studied for their roles in improving mitochondrial function and reducing oxidative stress. However, role of valine in mitochondrial function regulation and oxidative stress management remains elusive. This study investigated valine effect on mitochondrial function and oxidative stress in vitro. Valine increased expression of genes involved in mitochondrial biogenesis and dynamics. It upregulates mitochondrial function at complexes I, II, and IV levels of electron transport chain. Flow cytometry studies revealed, valine reduced oxidative stress by significantly lowering mitochondrial reactive oxygen species and protein expression of 4-hydroxynonenal. Functional role of valine against oxidative stress was analyzed by XFe96 Analyzer. Valine sustained oxidative phosphorylation and improved ATP generation rates during oxidative stress. In conclusion, our findings shed more light on the critical function of valine in protecting mitochondrial function thereby preventing mitochondrial/cellular damage induced by oxidative stress.

P. gingivalis-LPS Induces Mitochondrial Dysfunction Mediated by Neuroinflammation through Oxidative Stress.

Porphyromonas gingivalis (P. gingivalis), a key pathogen in periodontitis, is associated with neuroinflammation. Periodontal disease increases with age; 70.1% of adults 65 years and older have periodontal problems. However, the P. gingivalis- lipopolysaccharide (LPS)induced mitochondrial dysfunction in neurodegenerative diseases remains elusive. In this study, we investigated the possible role of P. gingivalis-LPS in mitochondrial dysfunction during neurodegeneration. We found that P. gingivalis-LPS treatment activated toll-like receptor (TLR) 4 signaling and upregulated the expression of Alzheimer's disease-related dementia and neuroinflammatory markers. Furthermore, the LPS treatment significantly exacerbated the production of reactive oxygen species and reduced the mitochondrial membrane potential. Our study highlighted the pivotal role of P. gingivalis-LPS in the repression of serum response factor (SRF) and its co-factor p49/STRAP that regulate the actin cytoskeleton. The LPS treatment repressed the genes involved in mitochondrial function and biogenesis. P. gingivalis-LPS negatively altered oxidative phosphorylation and glycolysis and reduced total adenosine triphosphate (ATP) production. Additionally, it specifically altered the mitochondrial functions in complexes I, II, and IV of the mitochondrial electron transport chain. Thus, it is conceivable that P. gingivalis-LPS causes mitochondrial dysfunction through oxidative stress and inflammatory events in neurodegenerative diseases.

Understanding the binding specificities of mRNA targets by the mammalian Quaking protein.

Mammalian Quaking (QKI) protein, a member of STAR family of proteins is a mRNA-binding protein, which post-transcriptionally modulates the target RNA. QKI protein possesses a maxi-KH domain composed of single heterogeneous nuclear ribonucleoprotein K homology (KH) domain and C-terminal QUA2 domain, that binds a sequence-specific QKI RNA recognition element (QRE), CUAAC. To understand the binding specificities for different mRNA sequences of the KH-QUA2 domain of QKI protein, we introduced point mutations at different positions in the QRE resulting in twelve different mRNA sequences with single nucleotide change. We carried out long unbiased molecular dynamics simulations using two different sets of recently updated forcefield parameters: AMBERff14SB+RNAχOL3 and CHARMM36 (with CMAP correction). We analyzed the changes in intermolecular dynamics as a result of mutation. Our results show that AMBER forcefields performed better to model the interactions between mRNA and protein. We also calculated the binding affinities of different mRNA sequences and found that the relative order correlates to the reported experimental studies. Our study shows that the favorable binding with the formation of stable complex will occur when there is an increase of the total intermolecular contacts between mRNA and protein, but without the loss of native contacts within the KH-QUA domain.

Short-Term Ingestion of Essential Amino Acid Based Nutritional Supplements or Whey Protein Improves the Physical Function of Older Adults Independently of Gut Microbiome.

SCOPE: Dietary proteins and essential amino acids (EAAs) are the major nutritional supplements that support the growth and activity of gut microbes contributing to the wellbeing of their host. This study hypothesizes that daily supplementation of the diet with either EAAs or whey protein for 12 weeks would improve the gut microbiome of older adults. METHODS AND RESULTS: The stool samples are processed and subjected to Illumina-based 16S ribosomal ribonucleic acid (rRNA) gene amplicon sequencing. In both groups, the most abundant families are found in order of relative abundance included: Bacteroidaceae, Lachnospiraceae, Ruminococcaceae, Prevotellaceae, Rikenellaceae, Enterobacteriaceae, Oscillospiraceae, Tannerellaceae, and Akkermansiaceae, which indicate that these subjects are able to maintain a same healthy microbial diversity in their guts. A significant finding is a reduction of proinflammatory cytokine, interleukin-18 (IL-18) in the EAAs group. It also uses the standard 6-min walking test (6MWT) as a measure of cardiopulmonary fitness. At the end of the study, the subjects in the EAAs group perform significantly better in the 6MWT as compared to the whey group. CONCLUSION: It seems plausible that the improved physical performance and reduced proinflammatory cytokine, IL-18 seen in the EAAs group, are independent of changes in gut microbiota.

A global multicenter propensity-matched analysis of mortality risk and palliative care referral due to cirrhosis in hospitalized patients with COVID-19.

Background and Aim: A few recent studies identified cirrhosis as a risk factor for high mortality in patients with coronavirus disease-19 (COVID-19). Palliative care is less often involved in the management of cirrhosis. We analyzed a global multicenter database to study the risk of mortality and palliative care referrals in patients with COVID-19 and cirrhosis. Methods: A federated cloud-based network (TriNetX) data from 50 health-care organizations across the globe were analyzed retrospectively. Patients with COVID-19 aged from 18 years to 90 years were identified between January 20, 2020, and November 16, 2020. Results: A total of 1969 patients (Group A) with COVID-19 and cirrhosis and 169,257 patients with COVID-19 alone (Group B) were studied. The two groups had a similar occurrence of other comorbid diseases. In a propensity-matched analysis, the mortality rate in Group A (8.9%) was significantly higher than Group B (5.6%), hazard ratio (95% confidence interval) for mortality with cirrhosis was 1.59 (1.26-1.99) (P = 0.01). The occurrence of palliative care referrals in Group A (4.1%) was significantly higher than Group B (2.0%), hazard ratio (95% confidence interval) with cirrhosis was 2.02 (1.39-2.94) (P = 0.01). Conclusion: Mortality rate and palliative care referrals were higher in patients with cirrhosis and COVID-19 compared to those with COVID-19 alone. This increased occurrence of palliative care referrals compared to the general trend in cirrhotic patients probably indicates increased awareness of COVID-19 as a life-threatening condition. Relevance for Patients: Cirrhosis should be identified as a high-risk condition that may require palliative care referral in hospitalized patients with COVID-19. Hospital resource utilization and cost-analysis modeling should anticipate the need for palliative care referrals as a significant outcome in patients with cirrhosis who are hospitalized with COVID-19.

Quality Improvement in Delirium Health Literacy in Older Adult Patients and Their Caregivers Attending a Geriatric Clinic.

Background: Delirium is a common medical condition that is highly prevalent in older adults who are at increased risk for its development with any illness, post-surgery or during hospitalization. The purpose of our study was to evaluate the health literacy of older adult patients and their caregivers about delirium, offer a brief educational intervention, and reevaluate their knowledge post intervention. Materials and Methods: We conducted a quality improvement project, focused on delirium health literacy in older adult patients ≥60 years and their caregivers. Delirium knowledge of participants was evaluated in a pre-education survey after which they were given a delirium education booklet to read. A post-education delirium survey was conducted within 2-3 weeks of the educational intervention. Chi-square test was used to analyze the knowledge base of older adults. Results: The study population consisted of a total of 70 older adults who participated in pre-education (n=35) and post-education (n=35) surveys. Older adult patients and their caregivers had significant knowledge gaps about the potential causes or etiologies, risk factors, symptomatology, and prevention of delirium in the pre-education survey. After the educational intervention, in the post-education survey, there were overall improvements in knowledge base of older adults in differentiating delirium with dementia (43% vs 94%, p<0.01) recognizing signs and symptoms (77% vs 94%, p<0.05), complications (76% vs 100%, p<0.01) and identifying the etiological factors associated with delirium. Conclusion: The quality improvement project demonstrated that older adults and caregivers have significant knowledge deficits about the common condition of delirium. This study also demonstrated that older adults were able to improve their health literacy regarding delirium after the intervention. Appropriate education on delirium for patients and caregivers might help in earlier identification, prevention, and better overall management of delirium.

Machine Learning Approaches to Classify Primary and Metastatic Cancers Using Tissue of Origin-Based DNA Methylation Profiles.

Metastatic cancers account for up to 90% of cancer-related deaths. The clear differentiation of metastatic cancers from primary cancers is crucial for cancer type identification and developing targeted treatment for each cancer type. DNA methylation patterns are suggested to be an intriguing target for cancer prediction and are also considered to be an important mediator for the transition to metastatic cancer. In the present study, we used 24 cancer types and 9303 methylome samples downloaded from publicly available data repositories, including The Cancer Genome Atlas (TCGA) and the Gene Expression Omnibus (GEO). We constructed machine learning classifiers to discriminate metastatic, primary, and non-cancerous methylome samples. We applied support vector machines (SVM), Naive Bayes (NB), extreme gradient boosting (XGBoost), and random forest (RF) machine learning models to classify the cancer types based on their tissue of origin. RF outperformed the other classifiers, with an average accuracy of 99%. Moreover, we applied local interpretable model-agnostic explanations (LIME) to explain important methylation biomarkers to classify cancer types.

Neuroprotective Effect of Quercetin in Combination with Piperine Against Rotenone- and Iron Supplement-Induced Parkinson's Disease in Experimental Rats.

Parkinson's disease (PD) is a neurodegenerative disorder caused by selective dopaminergic neuronal loss. Rotenone is a neurotoxin that selectively destroys dopaminergic neurons, leading to PD-like symptoms. Quercetin possesses antioxidant, anti-inflammatory, and neuroprotective properties but a major drawback is its low bioavailability. Therefore, the present study was designed to evaluate the neuroprotective effect of quercetin in combination with piperine against rotenone- and iron supplement-induced model of PD. Rotenone was administered at a dose of 1.5 mg/kg through an intraperitoneal route with iron supplement at a dose of 120 µg/g in diet from day 1 to day 28. Pre-treatment with quercetin (25 and 50 mg/kg, p.o.), piperine (2.5 mg/kg, p.o.) alone, quercetin (25 mg/kg, p.o.) in combination with piperine (2.5 mg/kg), and ropinirole (0.5 mg/kg, i.p.) was administered for 28 days 1 h prior to rotenone and iron supplement administration. All behavioral parameters were assessed on weekly basis. On the 29th day, all animals were sacrificed and striatum was isolated for biochemical (LPO, nitrite, GSH, mitochondrial complexes I and IV), neuroinflammatory (TNF-α, IL-1ß, and IL-6), and neurotransmitter (dopamine, norepinephrine, serotonin, GABA, glutamate) estimation. Quercetin treatment attenuated rotenone- and iron supplement-induced motor deficits and biochemical and neurotransmitter alterations in experimental rats. However, combination of quercetin (25 mg/kg) with piperine (2.5 mg/kg) significantly enhanced its neuroprotective effect as compared with treatment with quercetin alone. The study concluded that combination of quercetin with piperine contributed to superior antioxidant, anti-inflammatory, and neuroprotective effect against rotenone- and iron supplement-induced PD in experimental rats.

Altered gut microbiota and intestinal permeability in Parkinson's disease: Pathological highlight to management.

Parkinson's disease (PD) is a multifactorial neurodegenerative disorder, affecting 3.7% of the population over 65 years of age. PD involves degeneration of dopaminergic neurons in the substantia nigra pars compacta (SNPC) with deficiency of dopamine. Genetic factors like SNCA, PARK-2, PARK-7, PINK-1 and LRRK-2 as well as environmental toxins enhance alpha-synuclein, amyloid ß (beta) and τ (tau) proteins aggregation. Moreover, oxidative stress, mitochondrial dysfunctioning, neuroinflammation, prion like phenomena, excitotoxicity, mutations etc are known to cause pathological insult in PD. Recently, facts indicates strong correlation between gut-brain axis and PD. The communication between the gastrointestinal system (GIT) and central nervous system is bidirectional and it is hypothesized that PD arises in the gut and spreads to brain via vagus nerve that helps to propagate the alpha-synuclein that target brain. The Lewy bodies are found in olfactory bulb, dorsal motor vagal nerve and the ENS of the gut indicate peripheral and central correlation. The alteration of gut microbial flora leads to GIT disturbance which cause neuroinflammation by prion alpha-synuclein expression and produces PD like symptoms. Persistent gut inflammation with spontaneous neuroinflammation is yet need to confirm but increased intestinal permeability and disrupt function of GIT is known to produce non-motor symptoms of PD. The present review is aimed to explore mechanistic approach for gut associated PD symptoms as well as use of probiotics and prebiotics as therapeutic approach to retain gut microbial flora and prevent PD like symptoms.

Mitochondrial dysfunctioning and neuroinflammation: Recent highlights on the possible mechanisms involved in Traumatic Brain Injury.

Traumatic brain injury (TBI) is the injury to the vasculature of brain while trauma caused by physical, chemical and biological stimuli. TBI is the leading cause of mortality and morbidity around the world. In this, primary insult leads to secondary injury through the involvement and initiation of various pathological processes. The most citable includes excitotoxicity, Blood Brain Barrier (BBB) dysfunction, inflammation, mitochondrial dysfunction, oxidative stress, calcium efflux, microglial mediated release of proinflammatory mediators (cytokine, chemokines, interleukin, tissue necrosis factor etc.). The morphological changes in TBI are proportional to mitochondrial dysfunctioning and microglial activation, which play an assorted role in neurodegeneration following traumatic brain injury. It is also assumed that the release of nitric oxide, activation of microglial cells plays a diversive role in maintaining the physiological and pathological balance. This review cites different pathophysiological mechanisms that are involved in progenesis of secondary injury after primary insult. These targets further are useful to explore the deep molecular mechanisms and to analyse the effectiveness of available drugs. Moreover, the present review reflects the underlying inflammatory cascade responsible for neuronal loss and neurological deficit in TBI.

Evaluation of health potential of nutritionally enriched Kodo millet (Eleusine coracana) grown in Himachal Pradesh, India.

In this study, Kodo millet grains were phytochemically investigated for their nutritional and antioxidant potential for their use as functional foods. Methanolic extracts of grains showed higher phenolic content and antioxidant activity. TLC studies of the extracted polyphenols from kodo millet showed the predominant presence of ferulic acid and cinnamic acid in the millet. Further quantification of these polyphenols was done by using HPLC, analysing ferulic acid and cinnamic acid. Antagonistic spectrum of the polyphenols extracted showed inhibition against four bacterial test indicators viz. Staphylococcus aureus, Leuconostoc mesenteroides, Bacillus cereus and Enterococcus faecalis proving its antimicrobial action. The grains of kodo millet grains taken under study were found to posses' high protein, carbohydrates, minerals, crude fibers, polyphenols and antioxidants thus can be used as a good source of nutrition with additional health benefits.