Cell Defense Research Articles

Cannabidiol Enhances Mitochondrial Metabolism and Antioxidant Defenses in Human Intestinal Epithelial Caco-2 Cells

Background: The reintroduction of hemp production has resulted in increased consumption of cannabidiol (CBD) products, particularly CBD oil, yet their effects on intestinal health are not fully understood. Proper mitochondrial function and antioxidant defenses are vital for maintaining the intestinal epithelial barrier. AMP-activated protein kinase (AMPK) and peroxisome proliferator-activated receptor gamma coactivator (PGC)1α are key mediators of mitochondrial metabolism. Methods & Results: Using Caco-2 cells, we found that CBD oil promoted AMPK phosphorylation, upregulated differentiation markers, and enhanced PGC1α/SIRT3 mitochondrial signaling. CBD oil reduced reactive oxygen species production and increased antioxidant enzymes. Moreover, CBD oil also increased levels of citrate, malate, and succinate—key metabolites of the tricarboxylic acid cycle—alongside upregulation of pyruvate dehydrogenase and isocitrate dehydrogenase 1. Similarly, pure CBD induced metabolic and antioxidant signaling. Conclusions: CBD enhances mitochondrial metabolic activity and antioxidant defense in Caco-2 cells, making it a promising candidate for treating intestinal dysfunction.

PTD-FNK Alleviated LPS-Induced Oxidative Stress of Boar Testicular Sertoli Cells via Keap1-Nrf2 Pathway

PTD-FNK, a synthetic anti-apoptotic protein, has been shown to potently alleviate cellular injuries. However, the effects of PTD-FNK on oxidative defense in boar testicular Sertoli cells (SCs) against oxidative injury has not been explored. In this study, we show that exposure of SCs to 100 mg/L lipopolysaccharide (LPS) for 12 h leads to decreased survival rate, superoxide dismutase (SOD) activity, and increased malondialdehyde (MDA). Treatment with 0.01 nmol/L PTD-FNK for 4 h significantly enhanced the activity of SOD, catalase (CAT), glutathione peroxidase (GSH-Px), and total antioxidant capacity (T-AOC) in SCs. Concurrently, PTD-FNK treatment effectively reduced the production of reactive oxygen species (ROS) and the levels of 8-hydroxy-2′-deoxyguanosine (8-OHdG) in SCs. Moreover, using His pull-down and LC-MS techniques, we identified PTD-FNK-interacting proteins and confirmed that this protective effect may be mediated by the regulation of the Keap1-Nrf2 signaling pathway by PTD-FNK. Therefore, PTD-FNK alleviates LPS-induced oxidative stress via the Keap1/Nrf2 pathway, providing novel insights for the development of therapeutic agents targeting testicular oxidative damage.

Antiviral Effect of Melatonin on Caco-2 Cell Organoid Culture: Trick or Treat?

Melatonin is a hormone naturally produced by the body that has recently been found to have antiviral properties. However, its antiviral mechanisms are not entirely understood. Using Caco-2 cells, we developed a gastrointestinal organoid model to investigate the impact of melatonin on cellular organoid culture response to Poly I:C-induced viral inflammation in the gastrointestinal tract. Melatonin was found to have different effect when applied as a pretreatment before the induction of viral inflammation or as a treatment after it. Melatonin pretreatment after Poly I:C stimulation did not protect organoids from size reduction but enhanced cell proliferation, especially when lower (1 and 10 µM) melatonin concentrations were used. On the other hand, treatment with melatonin after the induction of viral inflammation helped to maintain the size of the organoids while reducing cell proliferation. In pretreated cells, reduced IFNLR1 expression was found, while melatonin treatment increased IFNLR1 expression and reduced the production of viral cytokines, such as IFNλ1 and STAT1-3, but did not prevent from apoptosis. The findings of this study emphasize the importance of type III IFNs in antiviral defense in epithelial gastrointestinal cells and shed more light on the antiviral properties of melatonin as a potential therapeutic substance.

E2F3-dependent activation of FAM111B restricts mouse cytomegalovirus replication in primate cells.

Viruses must counteract host cell defenses to facilitate viral replication. Viruses with a narrow host range, such as the cytomegaloviruses, are unable to counteract cellular defenses in cells of a foreign species. However, little is known about the cellular host range factors restricting cytomegalovirus replication. Here, we show that mouse cytomegalovirus (MCMV) induces the expression of the FAM111 proteases and that FAM111B, but not FAM111A that has previously been shown to restrict the replication of polyomavirus and orthopoxvirus host range mutants, acts as a cellular factor suppressing MCMV replication in human and rhesus monkey cells. The identification of FAM111B as a host range factor should provide new insight into the physiological functions of this poorly characterized protein.

Bacteria-Mediated Tumor-Targeting Delivery of Multienzyme-Mimicking Covalent Organic Frameworks Promoting Pyroptosis for Combinatorial Sono-Catalytic Immunotherapy.

Pyroptosis, an inflammatory cell death, has attracted great attention for potentiating a strong immune response against tumor cells. However, developing powerful pyroptosis inducers and then activating specific pyroptosis still remains challenging. Herein, a PEG-CuP-COF@∆St nanosystem is rationally designed, consisting of PEG-CuP-COF nanozyme pyroptosis inducers and tumor-targeting bacteria of the Salmonella Typhimurium strain VNP20009 (ΔSt), with an affinity for the tumor hypoxic microenvironment. The PEG-CuP-COF nanozymes possessed excellent sonodynamic performance and multienzyme-mimicking activities to generate reactive oxygen species (ROS) and then induce potent pyroptosis. The superoxide dismutase- and peroxidase-mimicking activities of PEG-CuP-COF catalytically produced hydrogen peroxide (H2O2) and hydroxyl radicals (•OH) which have important value in triggering acute inflammatory responses and pyroptosis. Moreover, PEG-CuP-COF showed outstanding glutathione peroxidase-mimicking activities, impairing the antioxidant defense in tumor cells and enhancing sonodynamic efficiency by making them more vulnerable to ROS-induced damage. During in vivo studies, PEG-CuP-COF@∆St nanosystem with its self-driven property exhibited impressive tumor-targeting capability and activated Caspase-3/gasdermin E-dependent pyroptosis to inhibit tumor growth. More importantly, it induced a powerful immune memory effect to prevent bone metastasis. In summary, this study introduces an innovative approach for combinatorial sono-catalytic immunotherapy using bacteria-mediated tumor-targeting delivery of nanozymes as specific pyroptosis inducers.

Genome-Wide Analysis of the Class III Peroxidase Gene Family in Physcomitrium patens and a Search for Clues to Ancient Class III Peroxidase Functions

Plant class III peroxidases (PRXs) catalyze generation of reactive oxygen species and oxidation of various compounds including lignin precursors. PRXs function in cell wall metabolism, defense, and stress responses. However, gene redundancy and catalytic versatility have impeded detailed functional characterization of PRX genes. The genome of the model moss Physcomitrium patens harbors a relatively small number (49) of PRX genes. Conserved architecture of four exons and three ‘001’ introns, found in some algal PRX genes and in the PpPRX family, suggests that this architecture predated divergence of the green algal and land plant lineages. The PpPRX family expanded mainly through whole-genome duplications. All duplicated pairs but one were under purifying selection and generally exhibited similar expression profiles. An expanded phylogenetic tree revealed a conserved land plant-wide clade that contained PRXs implicated in stress responses in non-lignifying cells, providing a clue to ancient functions of land plant PRXs. Functional clustering was not observed, suggesting convergent evolution of specific PRX functions (e.g., lignification) in different plant lineages. With its small complement of PRXs, P. patens may be useful for functional characterization of land plant PRXs. Several PpPRXs were proposed for further study, including PpPRX34 and PpPRX39 in the ancient land plant-wide clade.

Unravelling the genetic basis of Azoospermia: RNA-Sequence and transcriptome profiling analyses in a Greek Population.

ObjectiveTo investigate whether idiopathic non-obstructive azoospermia (iNOA) has its own transcriptomic signature. DesignTesticular tissue biopsies, were retrieved, processed and prepared for RNA extraction from 26 consented patients diagnosed with iNOA. Samples were grouped into four pools based on the presence of testicular spermatozoa: two replicate pools for “No presence” (Null-spz-1 & Null-spz-2 pools), one for “High presence” (High-spz pool) and one for “Rare presence” (Rare-spz pool). A second set of replicate pools (CF-1 & CF-2) was used from patients with obstructive azoospermia (OA), served as controls. RNA sequencing (RNA-seq) and comparative Transcriptomics Analysis (CTA) were performed, followed by differential gene expression analysis (DGE) focused on protein-coding genes only. Differentially expressed genes (DEGs) exclusively upregulated or downregulated were further analyzed using the Gene Ontology (GO), STRING, and Kyoto Encyclopedia of Genes and Genome (KEGG) bioinformatic platforms. SubjectsMales diagnosed with iNOA. ExposureTesticular biopsies from men diagnosed with iNOA. Main Outcome MeasuresProtein-coding differentially expressed genes (DEGs). ResultsA significantly altered transcriptomic profile of protein-coding genes was identified in the testicular tissues from men with iNOA. A total of 3858 genes, exhibited dysregulated expression, with 1994 genes being exclusively downregulated and 1734 upregulated. Biological processes (BPs) such as, male gamete generation (GO:0048232) and meiotic cycle (GO:0051321) were significantly enriched by the downregulated DEGs while the upregulated DEGs enriched BPs such as, regulation of cell death (GO:0010941), regulation of cell adhesion (GO:0030155) and defense response (GO:0006952). Interactome analysis identified hub genes among the downregulated DEGs, including PCNA, PLK1, MCM4, CDK1, CCNB1, AURKA, CCNA2, and CDC6 and among the upregulated DEGs, including EGFR, RELA, CTNNB1, MYC, JUN, SMAD3, STAT3 NFKB1, TGFB1 and ACTB. Additionally, KEGG analysis demonstrated that pathways such as cell cycle (hsa04110) and Oocyte meiosis (hsa04114) are the primarily affected by the downregulated genes, while the upregulated genes mainly affected pathways such as, the Focal adhesion (hsa04510) and the PI3-Akt signaling pathway (hsa04151). ConclusionA distinct mRNA expression profile and altered transcriptomic activity were identified in the testicular tissues of men with iNOA.

The secreted protein FonCHRD is essential for vegetative growth, asexual reproduction, and pathogenicity in watermelon Fusarium wilt fungus

Fungal pathogens often secrete numerous effectors to interfere with and/or suppress plant immunity to promote their infection. Watermelon Fusarium wilt, caused by the soil-borne fungus Fusarium oxysporum f. sp. niveum (Fon), is one of the devastating diseases that severely affect the watermelon industry. Here, we report the function of a candidate effector protein, FonCHRD, in Fon. FonCHRD harbors a chordin (CHRD) domain of unknown function and has a signal peptide with secretion activity. FonCHRD shows a relatively high expression level in Fon marcoconidia and is inducible by watermelon root tissues. Phenotypic analysis of the targeted deletion mutant revealed that FonCHRD plays roles in vegetative growth, asexual reproduction, and conidial morphology of Fon, while it is not involved in spore germination as well as cell wall, oxidative and salt stress responses. Deletion of FonCHRD impaired the ability to colonize and spread within host plants, significantly reducing its virulence on watermelon. FonCHRD is distributed across multiple compartments of plant cells but can target to the apoplast space in plants. FonCHRD inhibits the INF1- and Bcl2-associated X protein-triggered cell death and defense gene expression in transiently expressed Nicotiana benthamiana leaves. These findings suggest that FonCHRD is essential for Fon pathogenicity by modulating invasive growth and spreading abilities as well as by suppressing plant immune responses.

Modular Nanotransporters Deliver Anti-Keap1 Monobody into Mouse Hepatocytes, Thereby Inhibiting Production of Reactive Oxygen Species.

Background/Objectives: The study of oxidative stress in cells and ways to prevent it attract increasing attention. Antioxidant defense of cells can be activated by releasing the transcription factor Nrf2 from a complex with Keap1, its inhibitor protein. The aim of the work was to study the effect of the modular nanotransporter (MNT) carrying an R1 anti-Keap1 monobody (MNTR1) on cell homeostasis. Methods: The murine hepatocyte AML12 cells were used for the study. The interaction of fluorescently labeled MNTR1 with Keap1 fused to hrGFP was studied using the Fluorescence-Lifetime Imaging Microscopy-Förster Resonance Energy Transfer (FLIM-FRET) technique on living AML12 cells transfected with the Keap1-hrGFP gene. The release of Nrf2 from the complex with Keap1 and its levels in the cytoplasm and nuclei of the AML12 cells were examined using a cellular thermal shift assay (CETSA) and confocal laser scanning microscopy, respectively. The effect of MNT on the formation of reactive oxygen species was studied by flow cytometry using 6-carboxy-2',7'-dichlorodihydrofluorescein diacetate. Results: MNTR1 is able to interact with Keap1 in the cytoplasm, leading to the release of Nrf2 from the complex with Keap1 and a rapid rise in Nrf2 levels both in the cytoplasm and nuclei, ultimately causing protection of cells from the action of hydrogen peroxide. The possibility of cleavage of the monobody in endosomes leads to an increase in the observed effects. Conclusions: These findings open up a new approach to specifically modulating the interaction of intracellular proteins, as demonstrated by the example of the Keap1-Nrf2 system.

Characterizing metabolome signature of colostrum, transition and mature milk of indigenous cows (Bos indicus) adapted to high altitude environment of Leh-Ladakh

This study has identified 46 metabolites in colostrum, transition milk and mature milk of unique indigenous high altitude adapted Ladakhi cows using 1D 1H 800 MHz NMR spectroscopy. The multivariate analysis revealed that UDP-galactose, UDP-glucose, citrate, creatine phosphate, myo-inositol, lactose, 2-oxoglutarate, valine, maltose, leucine, dimethylamine, and choline with high VIP scores could differentiate the colostrum, transition and mature milk in separate clusters. . Highly enriched metabolites in colostrum such as UDP-galactose, UDP-glucose play crucial roles in cell growth, differentiation, and defense responses. Similarly, the presence of branched chain amino acids in colostrum could be linked to mammary gland development, N-acetylglucosamine, N-acetyl carnitine, choline etc. in high concentration in colostrum l might be helping in growth and development of neonatal calves of Ladakhi cows under hypoxia environment. Overall, this study has helped to characterize the metabolomic signatures of milk/colostrum of Ladakhi cows adapted to high altitude and cold desert of Leh-Ladakh.

IRE1α silences dsRNA to prevent taxane-induced pyroptosis in triple-negative breast cancer.

Chemotherapy is often combined with immune checkpoint inhibitor (ICIs) to enhance immunotherapy responses. Despite the approval of chemo-immunotherapy in multiple human cancers, many immunologically cold tumors remain unresponsive. The mechanisms determining the immunogenicity of chemotherapy are elusive. Here, we identify the ER stress sensor IRE1α as a critical checkpoint that restricts the immunostimulatory effects of taxane chemotherapy and prevents the innate immune recognition of immunologically cold triple-negative breast cancer (TNBC). IRE1α RNase silences taxane-induced double-stranded RNA (dsRNA) through regulated IRE1-dependent decay (RIDD) to prevent NLRP3 inflammasome-dependent pyroptosis. Inhibition of IRE1α in Trp53-/- TNBC allows taxane to induce extensive dsRNAs that are sensed by ZBP1, which in turn activates NLRP3-GSDMD-mediated pyroptosis. Consequently, IRE1α RNase inhibitor plus taxane converts PD-L1-negative, ICI-unresponsive TNBC tumors into PD-L1high immunogenic tumors that are hyper-sensitive to ICI. We reveal IRE1α as a cancer cell defense mechanism that prevents taxane-induced danger signal accumulation and pyroptotic cell death.

Blood cell defence against pathogens

Blood cell defence against pathogens

Fatty acid synthase (FASN) is a tumor-cell-intrinsic metabolic checkpoint restricting T-cell immunity

Fatty acid synthase (FASN)-catalyzed endogenous lipogenesis is a hallmark of cancer metabolism. However, whether FASN is an intrinsic mechanism of tumor cell defense against T cell immunity remains unexplored. To test this hypothesis, here we combined bioinformatic analysis of the FASN-related immune cell landscape, real-time assessment of cell-based immunotherapy efficacy in CRISPR/Cas9-based FASN gene knockout (FASN KO) cell models, and mathematical and mechanistic evaluation of FASN-driven immunoresistance. FASN expression negatively correlates with infiltrating immune cells associated with cancer suppression, cytolytic activity signatures, and HLA-I expression. Cancer cells engineered to carry a loss-of-function mutation in FASN exhibit an enhanced cytolytic response and an accelerated extinction kinetics upon interaction with cytokine-activated T cells. Depletion of FASN results in reduced carrying capacity, accompanied by the suppression of mitochondrial OXPHOS and strong downregulation of electron transport chain complexes. Targeted FASN depletion primes cancer cells for mitochondrial apoptosis as it synergizes with BCL-2/BCL-XL-targeting BH3 mimetics to render cancer cells more susceptible to T-cell-mediated killing. FASN depletion prevents adaptive induction of PD-L1 in response to interferon-gamma and reduces constitutive overexpression of PD-L1 by abolishing PD-L1 post-translational palmitoylation. FASN is a novel tumor cell-intrinsic metabolic checkpoint that restricts T cell immunity and may be exploited to improve the efficacy of T cell-based immunotherapy.

Evaluating the Role of Nrf-2/HO-1 Pathway in Glioblastoma Treatment Efficacy: A Co-Culture Study

Objective: Glioblastoma (GB) is a highly lethal form of brain tumor. Although standard therapy appears to be effective, the survival time is quite short, and the recurrence rate is high. Bortezomib (BTZ), is a proteasome inhibitor, used in GB therapies and resulted in serious off-target effects. Carfilzomib (CFZ), is an alternative for BTZ, has known with nonserious off-target effects. This study aimed to examine the potential off-target effects caused by BTZ and CFZ in terms of the therapy related activation of antioxidant mechanisms regarding to Nuclear factor (erythroid-derived 2)-like 2 (Nrf-2)/Heme Oxygenase-1 (HO-1)-dependent response. Methods: GB cells were co-cultured with heathy astrocyte (HA) cells to mimic the tumor microenvironment in some extent. Cell viability was determined following ionizing radiation (IR), temozolomide (TMZ), BTZ and CFZ alone and in combination. Nrf-2 and HO-1 protein expressions were analyzed by western blotting assay. Results: Co-culture results showed that the GB cells in the BTZ-treated groups expressed higher levels of Nrf-2 and HO-1 than in the CFZtreated groups. In the HAs, the group treated with CFZ showed higher Nrf-2 expression than the group treated with BTZ alone, while the same groups in combination with TMZ&IR showed exactly opposite results. HO-1 expression was also not seen in any of the HA groups. Conclusion: The significant increase in Nrf-2 levels in the CFZ-treated group in the HAs could also be interpreted as CFZ promoting the defence of healthy cells against therapy-induced stress conditions. Although further studies are needed, these preliminary results show that the evaluation of CFZ as a second-line therapy could be a milestone for the treatment of GB.

Wheat TaNACα18 functions as a positive regulator of high-temperature adaptive responses and improves cell defense machinery.

Global wheat production amounted to >780 MMT during 2022-2023 whose market size are valued at >$128 billion. Wheat is highly susceptible to high-temperature stress (HTS) throughout the life cycle and its yield declines 5-7% with the rise in each degree of temperature. Previously, we reported an array of HTS-response markers from a resilient wheat cv. Unnat Halna and described their putative role in heat acclimation. To complement our previous results and identify the key determinants of thermotolerance, here we examined the cytoplasmic proteome of a sensitive cv. PBW343. The HTS-triggered metabolite reprograming highlighted how proteostasis defects influence the formation of an integrated stress-adaptive response. The proteomic analysis identified several promising HTS-responsive proteins, including a NACα18 protein, designated TaNACα18, whose role in thermotolerance remains unknown. Dual localization of TaNACα18 suggests its crucial functions in the cytoplasm and nucleus. The homodimerization of TaNACα18 anticipated its function as a transcriptional coactivator. The complementation of TaNACα18 in yeast and overexpression in wheat demonstrated its role in thermotolerance across the kingdom. Altogether, our results suggest that TaNACα18 imparts tolerance through tight regulation of gene expression, cell wall remodeling and activation of cell defense responses.

Relationship between Oxidative Stress and Cellular Adenosine Triphosphate Levels

Oxidative stress (OS) refers to the deterioration of the balance between oxidants and antioxidants in favor of oxidants, and this may lead to disruptions in redox signaling and control and/or damage at the molecular level. The presence of low levels of reactive oxygen species (ROS) plays a physiological role in intracellular signaling pathways. However, damage may occur in cells and tissues as a result of excessive increase in ROS production. Because ROS have the potential to damage almost all structures in the cell, including lipid, protein, deoxyribo nucleicacid (DNA). The main source of free radicals in the cell is mitochondria. ROS formation is a natural consequence of oxidative phosphorylation resulting in adenosine triphosphate (ATP) production in mitochondria. The attack of these radicals results in damage to the mitochondria, a decrease in the activity of oxidative phosphorylation enzymes and consequently a decrease in ATP synthesis. On the other hand, ATP is needed for antioxidant synthesis, which is necessary for cell defence against increasing ROS. Therefore, a decrease in ATP levels makes tissues vulnerable to OS. In this case, it is likely that tissues exposed to OS will also have problems in ATP production and the decrease in ATP synthesis will further increase oxidative damage.

Chlamydia-containing spheres are a novel and predominant form of egress by the pathogen Chlamydia psittaci.

The egress of intracellular bacteria from host cells and cellular tissues is a critical process during the infection cycle. This process is essential for bacteria to spread inside the host and can influence the outcome of an infection. For the obligate intracellular Gram-negative zoonotic bacterium Chlamydia psittaci, little is known about the mechanisms resulting in bacterial egress from the infected epithelium. Here, we describe and characterize Chlamydia-containing spheres (CCSs), a novel and predominant type of non-lytic egress utilized by Chlamydia spp. CCSs are spherical, low-phase contrast structures surrounded by a phosphatidylserine-exposing membrane with specific barrier functions. They contain infectious progeny and morphologically impaired cellular organelles. CCS formation is a sequential process starting with the proteolytic cleavage of a DEVD tetrapeptide-containing substrate that can be detected inside the chlamydial inclusions, followed by an increase in the intracellular calcium concentration of the infected cell. Subsequently, blebbing of the plasma membrane begins, the inclusion membrane destabilizes, and the proteolytic cleavage of a DEVD-containing substrate increases rapidly within the whole infected cell. Finally, infected, blebbing cells detach and leave the monolayer, thereby forming CCS. This sequence of events is unique for chlamydial CCS formation and fundamentally different from previously described Chlamydia egress pathways. Thus, CCS formation represents a major, previously uncharacterized egress pathway for intracellular pathogens that could be linked to Chlamydia biology in general and might influence the infection outcome in vivo.IMPORTANCEHost cell egress is essential for intracellular pathogens to spread within an organism and for host-to-host transmission. Here, we characterize Chlamydia-containing sphere (CCS) formation as a novel and predominant non-lytic egress pathway of the intracellular pathogens Chlamydia psittaci and Chlamydia trachomatis. CCS formation is fundamentally different from extrusion formation, the previously described non-lytic egress pathway of C. trachomatis. CCS formation is a unique sequential process, including proteolytic activity, followed by an increase in intracellular calcium concentration, inclusion membrane destabilization, plasma membrane blebbing, and the final detachment of a whole phosphatidylserine-exposing former host cell. Thus, CCS formation represents an important and previously uncharacterized egress pathway for intracellular pathogens that could possibly be linked to Chlamydia biology, including host tropism, protection from host cell defense mechanisms, or bacterial pathogenicity.

Amphicarpic development in Cardamine chenopodiifolia.

Amphicarpy is an unusual trait where two fruit types develop on the same plant: one above and the other belowground. This trait is not found in conventional model species. Therefore, its development and molecular genetics remain under-studied. Here, we establish the allooctoploid Cardamine chenopodiifolia as an emerging experimental system to study amphicarpy. We characterized C. chenopodiifolia development, focusing on differences in morphology and cell wall histochemistry between above- and belowground fruit. We generated a reference transcriptome with PacBio full-length transcript sequencing and analysed differential gene expression between above- and belowground fruit valves. Cardamine chenopodiifolia has two contrasting modes of seed dispersal. The main shoot fails to bolt and initiates floral primordia that grow underground where they self-pollinate and set seed. By contrast, axillary shoots bolt and develop exploding seed pods aboveground. Morphological differences between aerial explosive fruit and subterranean nonexplosive fruit were reflected in a large number of differentially regulated genes involved in photosynthesis, secondary cell wall formation and defence responses. Tools established in C. chenopodiifolia, such as a reference transcriptome, draft genome assembly and stable plant transformation, pave the way to study amphicarpy and trait evolution via allopolyploidy.

Effects of physical inactivity behavior during COVID-19 pandemic on physical fitness, body composition, inflammatory cytokine, and immunocytes in older adults: A retrospective and prospective study

The prolonged period of COVID-19 has ingrained physical inactivity as a habit, leading to a reluctance to move. This has resulted in a decline in physical fitness and the loss of a healthy body composition. While this trend is particularly noticeable among the older adults, its impact on the immune cell defense system, which is crucial for minimizing viral infections, remains unclear. This study aimed to investigate the physical fitness, body composition, cytokines and immunocytes of older adults who engaged in physical activity (PA) before the COVID-19 pandemic but had to stop it due to the lockdown. A total of 172 older adults aged 61 to 85 years participated in this study: 90 in non-PA group (NPAG, 34 men and 56 women), and 82 in PA group (PAG, 29 men and 53 women). Physical inactivity was 45.13 ± 5.67 weeks in the NPAG and 1.70 ± 0.43 weeks in the PAG. Although there was no significant difference in calorie intake, PA volume showed a significant decrease in NPGA (P < 0.001). VO₂max, strength, and sit-ups decreased in NPAG, whereas they maintained or increased in PAG (Ps < 0.001). NPAG experienced an increase in fat mass (∼33.0 %), along with a decrease in muscle mass (∼10.4 %), but PAG showed slight increases (∼1.1 % vs. ∼1.5 %, Ps < 0.001). Interleukin-6 (∼38.9 %), tumor necrosis factor-α (∼38.3 %), and C-reactive protein (∼33.6 %) increased, whereas immunocytes decreased in NPAG (Ps < 0.001). In contrast, those in PAG showed the opposite phenomenon. This study indicates that even during the COVID-19 situation, maintaining active PA in the older adults helps retain beneficial physical fitness and body composition, reduces inflammatory factors, and contributes to preserving or enhancing the function of immunocytes.

LncRNA Nostrill promotes interferon-γ-stimulated gene transcription and facilitates intestinal epithelial cell-intrinsic anti-Cryptosporidium defense.

Intestinal epithelial cells possess the requisite molecular machinery to initiate cell-intrinsic defensive responses against intracellular pathogens, including intracellular parasites. Interferons(IFNs) have been identified as cornerstones of epithelial cell-intrinsic defense against such pathogens in the gastrointestinal tract. Long non-coding RNAs (lncRNAs) are RNA transcripts (>200 nt) not translated into protein and represent a critical regulatory component of mucosal defense. We report here that lncRNA Nostrill facilitates IFN-γ-stimulated intestinal epithelial cell-intrinsic defense against infection by Cryptosporidium, an important opportunistic pathogen in AIDS patients and a common cause of diarrhea in young children. Nostrill promotes transcription of a panel of genes controlled by IFN-γ through facilitating Stat1 chromatin recruitment and thus, enhances expression of several genes associated with cell-intrinsic defense in intestinal epithelial cells in response to IFN-γ stimulation, including Igtp, iNos, and Gadd45g. Induction of Nostrill enhances IFN-γ-stimulated intestinal epithelial defense against Cryptosporidium infection, which is associated with an enhanced autophagy in intestinal epithelial cells. Our findings reveal that Nostrill enhances the transcription of a set of genes regulated by IFN-γ in intestinal epithelial cells. Moreover, induction of Nostrill facilitates the IFN-γ-mediated epithelial cell-intrinsic defense against cryptosporidial infections.