Heyde Syndrome Unveiled: A Case Report with Current Literature Review and Molecular Insights.

Heyde syndrome, marked by aortic stenosis, gastrointestinal bleeding from angiodysplasia, and acquired von Willebrand syndrome, is often underreported. Shear stress from a narrowed aortic valve degrades von Willebrand factor multimers, leading to angiodysplasia formation and von Willebrand factor deficiency. This case report aims to raise clinician awareness of Heyde syndrome, its complexity, and the need for a multidisciplinary approach. We present a 75-year-old man with aortic stenosis, gastrointestinal bleeding from angiodysplasia, and acquired von Willebrand syndrome type 2A. The patient was successfully treated with argon plasma coagulation and blood transfusions. He declined further treatment for aortic stenosis but was in good overall health with improved laboratory results during follow-up. Additionally, we provide a comprehensive review of the molecular mechanisms involved in the development of this syndrome, discuss current diagnostic and treatment approaches, and offer future perspectives for further research on this topic.

Cutting-Edge iPSC-Based Approaches in Studying Host-Microbe Interactions in Neuropsychiatric Disorders.

Gut microbiota (GM), together with its metabolites (such as SCFA, tryptophan, dopamine, GABA, etc.), plays an important role in the functioning of the central nervous system. Various neurological and psychiatric disorders are associated with changes in the composition of GM and their metabolites, which puts them in the foreground as a potential adjuvant therapy. However, the molecular mechanisms behind this relationship are not clear enough. Therefore, before considering beneficial microbes and/or their metabolites as potential therapeutics for brain disorders, the mechanisms underlying microbiota-host interactions must be identified and characterized in detail. In this review, we summarize the current knowledge of GM alterations observed in prevalent neurological and psychiatric disorders, multiple sclerosis, major depressive disorder, Alzheimer's disease, and autism spectrum disorders, together with experimental evidence of their potential to improve patients' quality of life. We further discuss the main obstacles in the study of GM-host interactions and describe the state-of-the-art solution and trends in this field, namely "culturomics" which enables the culture and identification of novel bacteria that inhabit the human gut, and models of the gut and blood-brain barrier as well as the gut-brain axis based on induced pluripotent stem cells (iPSCs) and iPSC derivatives, thus pursuing a personalized medicine agenda for neuropsychiatric disorders.

Insight into the Probiogenomic Potential of Enterococcus faecium BGPAS1-3 and Application of a Potent Thermostable Bacteriocin.

This study aimed to investigate the probiogenomic features of artisanal bacteriocin-producing Enterococcus faecium BGPAS1-3 and the use of the improved pMALc5HisEk expression vector for overexpressing class II bacteriocins and the application of purified bacteriocin 31 in a milk model as a preservative against L. monocytogenes. The BGPAS1-3 strain was isolated from traditional fresh soft cheese manufactured in households on a small scale in rural locations surrounding Pale Mountain City in Bosnia and Herzegovina. The whole-genome sequencing approach and bioinformatics analyses revealed that the strain BGPAS1-3 was non-pathogenic to humans. The presence of bacteriocin operons suggested the ability of the isolate to suppress the growth of pathogens. Coding regions for three maturated bacteriocins (bacteriocin 31, bacteriocin 32, and enterocin P) produced by BGPAS1-3 were amplified and expressed in Escherichia coli ER2523 using the pMALc5HisEk system. All three bacteriocins were successfully overexpressed and purified after enterokinase cleavage but showed different antimicrobial activity. Bacteriocin 31 showed significantly stronger antimicrobial activity compared with bacteriocin 32. It was the only one that proved to be suitable for use as a food preservative against L. monocytogenes in a milk model.

Postbiotic lactobacilli induce cutaneous antimicrobial response and restore the barrier to inhibit the intracellular invasion of Staphylococcus aureus in vitro and ex vivo.

Intracellular pathogens including Staphylococcus aureus contribute to the non-healing phenotype of chronic wounds. Lactobacilli, well known as beneficial bacteria, are also reported to modulate the immune system, yet their role in cutaneous immunity remains largely unknown. We explored the therapeutic potential of bacteria-free postbiotics, bioactive lysates of lactobacilli, to reduce intracellular S. aureus colonization and promote healing. Fourteen postbiotics derived from various lactobacilli species were screened, and Latilactobacillus curvatus BGMK2-41 was selected for further analysis based on the most efficient ability to reduce intracellular infection by S. aureus diabetic foot ulcer clinical isolate and S. aureus USA300. Treatment of both infected keratinocytes in vitro and infected human skin ex vivo with BGMK2-41 postbiotic cleared S. aureus. Keratinocytes treated in vitro with BGMK2-41 upregulated expression of antimicrobial response genes, of which DEFB4, ANG, and RNASE7 were also found upregulated in treated ex vivo human skin together with CAMP exclusively upregulated ex vivo. Furthermore, BGMK2-41 postbiotic treatment has a multifaceted impact on the wound healing process. Treatment of keratinocytes stimulated cell migration and the expression of tight junction proteins, while in ex vivo human skin BGMK2-41 increased expression of anti-inflammatory cytokine IL-10, promoted re-epithelialization, and restored the epidermal barrier via upregulation of tight junction proteins. Together, this provides a potential therapeutic approach for persistent intracellular S. aureus infections.

The use of vitreous humour as a potential source of DNA for postmortem identification in forensic science.

Vitreous humour (VH) is routinely collected for toxicological analyses. However, only a few studies have examined its possible use in genotyping. Because of its isolation from the rest of the body, later onset of postmortem changes, and availability, VH could be a potential source of DNA for postmortem identification and other molecular analyses in forensic genetics. During forensic autopsies, samples of different VH volumes (5 ml, 4 ml, 3 ml, 2 ml, 1 ml, and 0.5 ml) were taken from 66 cadavers 24-48 h after death. DNA was also isolated from the samples immediately after collection and after a specific time of storage (1, 2, and 6 months). DNA was isolated using phenol‒chloroform‒isoamyl alcohol (PCI), and the yield and purity of the obtained DNA were determined spectrophotometrically using a FastGene NanoView Photometer. The integrity of the isolated DNA molecule was determined by PCR amplification of the hTERT (113 bp) gene. The results showed that VH could be a reliable source of genetic material for forensic analysis, and the method used for DNA extraction was effective. The yield of the isolated DNA ranged from 6.20 to 609.5 ng/µl, and the purity of the samples was 1.24-2.34. The isolated DNA concentration and integrity depend on the sample volume, but the DNA purity does not. It is also shown that DNA can be extracted from VH samples that have been stored for up to 6 months at - 20 °C. Therefore, using VH can be a valuable material for DNA identification.

The changes in tissue histomorphology and quality of DNA in healthy human autopsied tissues stored at -20 °C and -150 °C.

The aim of this study was to compare the changes in tissue histomorphology and DNA quality in six different healthy tissues (brain, heart, lung, liver, spleen and kidney) exempted during autopsy of healthy individuals and storage at -20 °C and -150 °C three month. Tissue samples were obtained, divided by tissue and temperature group, and for each sample, tissue histomorphology and DNA (isolated from all tissues in duplicated - 72 samples of DNA) quality were analysed. Morphology of tissue samples was studied using H&E staining. DNA was isolated using the phenol-chloroform-isoamyl alcohol method. To assess the concentration and purity of the DNA samples, we used a spectrophotometer to measure absorbance at wavelengths of 280 nm and 260 nm. The fragments of human telomerase reverse transcriptase (hTERT) gene were amplified from the DNA using PCR reaction and then visualised using the 2 % agarose gel. Samples stored at -150 °C sustained the highest degree of histomorphological damage, while samples stored at -20 °C were less degraded, compared to control. The liver samples stored at -20 °C had a mean DNA concentration (1030.4 ± 51.5 ng/µl) higher than the samples of liver tissue stored at -150 °C (497.4 ± 167.1 ng/µl) (p < 0.001). Other tissues did not have statistically significantly different DNA concentration at both temperatures. Liver samples at -20 °C had degraded DNA, showed as the absence of hTERT gene in most of samples. Other tissue samples in both temperature groups had unfragmented DNA. Storing tissue samples at -20 °C is not inferior in terms of DNA yield and integrity, and possibly superior for tissue histomorphology, comparing with samples stored at -150°C.

Insight into the Postbiotic Potential of the Autochthonous Bacteriocin-Producing Enterococcus faecium BGZLM1-5 in the Reduction in the Abundance of Listeria monocytogenes ATCC19111 in a Milk Model.

This study aimed to explore the probiogenomic characteristics of artisanal bacteriocin-producing Enterococcus faecium BGZLM1-5 and its potential application in reducing Listeria monocytogenes in a milk model. The BGZLM1-5 strain was isolated from raw cow's milk from households in the Zlatar Mountain region. The whole genome sequencing approach and bioinformatics analyses reveal that the strain BGZLM1-5 is non-pathogenic to humans. Bacteriocin-containing supernatant was thermally stable and antimicrobial activity retained 75% of the initial activity compared with that of the control after treatment at 90 °C for 30 min. Antimicrobial activity maintained relative stability at pH 3-11 and retained 62.5% of the initial activity compared with that of the control after treatment at pH 1, 2, and 12. The highest activity of the partially purified bacteriocin was obtained after precipitation at 40% saturation with ammonium sulfate and further purification by mixing with chloroform. Applying 3% and 5% (v/v) of the bacteriocin-containing supernatant and 0.5% (v/v) of the partially purified bacteriocin decreased the viable number of L. monocytogenes ATCC19111 after three days of milk storage by 23.5%, 63.5%, and 58.9%, respectively.

Pomegranate Peel Extract Differently Modulates Gene Expression in Gingiva-Derived Mesenchymal Stromal Cells under Physiological and Inflammatory Conditions.

Pomegranate has shown a favorable effect on gingivitis/periodontitis, but the mechanisms involved are poorly understood. The aim of this study was to test the effect of pomegranate peel extract (PoPEx) on gingiva-derived mesenchymal stromal cells (GMSCs) under physiological and inflammatory conditions. GMSC lines from healthy (H) and periodontitis (P) gingiva (n = 3 of each) were established. The lines were treated with two non-toxic concentrations of PoPEX (low-10; high-40 µg/mL), with or without additional lipopolysaccharide (LPS) stimulation. Twenty-four genes in GMSCs involved in different functions were examined using real-time polymerase chain reaction (RT-PCR). PoPEx (mostly at higher concentrations) inhibited the basal expression of IL-6, MCP-1, GRO-α, RANTES, IP-10, HIF-1α, SDF-1, and HGF but increased the expression of IL-8, TLR3, TGF-ß, TGF-ß/LAP ratio, IDO-1, and IGFB4 genes in H-GMSCs. PoPEx increased IL-6, RANTES, MMP3, and BMP2 but inhibited TLR2 and GRO-α gene expression in P-GMSCs. LPS upregulated genes for proinflammatory cytokines and chemokines, tissue regeneration/repair (MMP3, IGFBP4, HGF), and immunomodulation (IP-10, RANTES, IDO-1, TLR3, COX-2), more strongly in P-GMSCs. PoPEx also potentiated most genes' expression in LPS-stimulated P-GMSCs, including upregulation of osteoblastic genes (RUNX2, BMP2, COL1A1, and OPG), simultaneously inhibiting cell proliferation. In conclusion, the modulatory effects of PoPEx on gene expression in GMSCs are complex and dependent on applied concentrations, GMSC type, and LPS stimulation. Generally, the effect is more pronounced in inflammation-simulating conditions.

Assessment of stability and bioactive compounds in yogurt containing novel natural starter cultures with the ability to promote longevity in Caenorhabditis elegans.

Yogurt represent one of the oldest fermented foods containing viable lactic acid bacteria and many bioactive compounds that could exhibit beneficial effects on human health and train our immune system to better respond to invading pathogens. Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus are commonly used for yogurt preparation under controlled temperature and environmental conditions. In this study, we investigated probiotic features of S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21 strains isolated from artisanal sour milk and yogurt by using Caenorhabditis elegans as an in vivo model system. Further, we evaluated content of total fat, saturated fatty acids, proteins, and lactose, as well as vitamins and AA of yogurt prepared from above-mentioned starter cultures during 21 d of storage at 4°C to get insights of final product stability. We showed that S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21 strains applied in combination upregulated the expression of autophagy-related genes in C. elegans. Beside autophagy, we observed activation of TIR-1-dependent transcription of lysozyme-like antimicrobial genes involved in the immune defense of C. elegans. Upregulation of these genes strongly correlates with an increase in the longevity of the worms fed with yogurt culture bacteria. Further, we showed that yogurt prepared with S. thermophilus BGKMJ1-36 and L. bulgaricus BGVLJ1-21, as a final product, is rich with vitamin B2 and dominant AA known by their prolongevity properties. Taken together, our study pointed to the beneficial features of the tested starter cultures and yogurt and highlighted their potential to be used as a fermented food with added-value properties.

The quality of DNA isolated from autopsy formalin-fixed and formalin-fixed paraffin-embedded tissues: study of 1662 samples.

BACKGROUND: There are enormous formalin-fixed paraffin-embedded tissue archives and a constantly growing number of methods for molecular analyses but, the isolation of DNA from this tissue is still challenging due to the damaging effect of formalin on DNA. To determine the extent to which DNA purity, yield and integrity depend on the process of fixation in formalin, and to what extent on the process of tissue paraffin embedding, we compared the quality of DNA isolated from fixed tissues and DNA isolated from tissues embedded in paraffin blocks after fixation. METHODS AND RESULTS: Heart, liver and brain tissues obtained from healthy people who suddenly died a violent death were fixed in 10% buffered formalin as well as in 4% unbuffered formalin for 6 h, 1-7 days (every 24 h), 10, 14, 28 days and 2 months. Additionally, the same tissues were fixed in 4% unbuffered formalin embedded in a paraffin block and stored from a few months to 30 years. The yield and purity of the DNA samples isolated from these tissues were measured using spectrophotometry. PCR amplification of the hTERT gene was performed to evaluate the degree of DNA fragmentation. Although the purity of the DNA isolated from almost all tissue samples was satisfactory, the DNA yields changed significantly. There was a decrease in successful PCR amplification of the hTERT gene in DNA samples isolated from tissue fixed in buffered and unbuffered formalin for up to 2 months from 100% to 8.3%. Archiving the tissue in paraffin blocks for up to 30 years also impacts the integrity of DNA, so there was a decrease in PCR amplification of the hTERT gene from 91% success to 3%. CONCLUSION: The largest decrease in DNA yield was observed after tissue formalin fixation after 14 days of fixation in buffered and unbuffered formalin. DNA integrity depends on the time of tissue formalin fixation, especially after 6 days for tissue fixed in unbuffered formalin, while for tissue fixed in buffered formalin the time is prolonged up to 28 days. The age of paraffin blocks also impacted DNA integrity, after 1 year and 16 years of archiving the paraffin blocks of tissues, there was a decrease in the success of PCR amplification.

Myeloid-derived suppressor cells prevent disruption of the gut barrier, preserve microbiota composition, and potentiate immunoregulatory pathways in a rat model of experimental autoimmune encephalomyelitis.

Over-activated myeloid cells and disturbance in gut microbiota composition are critical factors contributing to the pathogenesis of Multiple Sclerosis (MS). Myeloid-derived suppressor cells (MDSCs) emerged as promising regulators of chronic inflammatory diseases, including autoimmune diseases. However, it remained unclear whether MDSCs display any therapeutic potential in MS, and how this therapy modulates gut microbiota composition. Here, we assessed the potential of in vitro generated bone marrow-derived MDSCs to ameliorate experimental autoimmune encephalomyelitis (EAE) in Dark Agouti rats and investigated how their application associates with the changes in gut microbiota composition. MDSCs differentiated with prostaglandin (PG)E2 (MDSC-PGE2) and control MDSCs (differentiated without PGE2) displayed strong immunosuppressive properties in vitro, but only MDSC-PGE2 significantly ameliorated EAE symptoms. This effect correlated with a reduced infiltration of Th17 and IFN-γ-producing NK cells, and an increased proportion of regulatory T cells in the CNS and spleen. Importantly, both MDSCs and MDSC-PGE2 prevented EAE-induced reduction of gut microbiota diversity, but only MDSC-PGE2 prevented the extensive alterations in gut microbiota composition following their early migration into Payer's patches and mesenteric lymph nodes. This phenomenon was related to the significant enrichment of gut microbial taxa with potential immunoregulatory properties, as well as higher levels of butyrate, propionate, and putrescine in feces. This study provides new insights into the host-microbiota interactions in EAE, suggesting that activated MDSCs could be potentially used as an efficient therapy for acute phases of MS. Considering a significant association between the efficacy of MDSC-PGE2 and gut microbiota composition, our findings also provide a rationale for further exploring the specific microbial metabolites in MS therapy.

Serum-derived extracellular vesicles: Novel biomarkers reflecting the disease severity of COVID-19 patients.

COVID-19 is characterized by a wide spectrum of disease severity, whose indicators and underlying mechanisms need to be identified. The role of extracellular vesicles (EVs) in COVID-19 and their biomarker potential, however, remains largely unknown. Aiming to identify specific EV signatures of patients with mild compared to severe COVID-19, we characterized the EV composition of 20 mild and 26 severe COVID-19 patients along with 16 sex and age-matched healthy donors with a panel of eight different antibodies by imaging flow cytometry (IFCM). We correlated the obtained data with 37 clinical, prerecorded biochemical and immunological parameters. Severe patients' sera contained increased amounts of CD13+ and CD82+ EVs, which positively correlated with IL-6-producing and circulating myeloid-derived suppressor cells (MDSCs) and with the serum concentration of proinflammatory cytokines, respectively. Sera of mild COVID-19 patients contained more HLA-ABC+ EVs than sera of the healthy donors and more CD24+ EVs than severe COVID-19 patients. Their increased abundance negatively correlated with disease severity and accumulation of MDSCs, being considered as key drivers of immunopathogenesis in COVID-19. Altogether, our results support the potential of serum EVs as powerful biomarkers for COVID-19 severity and pave the way for future investigations aiming to unravel the role of EVs in COVID-19 progression.

Immunomodulatory Properties of Pomegranate Peel Extract in a Model of Human Peripheral Blood Mononuclear Cell Culture.

Pomegranate peel extract (PoPEx) has been shown to have antioxidant and anti-inflammatory properties, but its effect on the adaptive immune system has not been sufficiently investigated. In this study, the treatment of human peripheral blood mononuclear cells (PBMC) with PoPEx (range 6.25-400 µg/mL) resulted in cytotoxicity at concentrations of 100 µg/mL and higher, due to the induction of apoptosis and oxidative stress, whereas autophagy was reduced. At non-cytotoxic concentrations, the opposite effect on these processes was observed simultaneously with the inhibition of PHA-induced PBMC proliferation and a significant decrease in the expression of CD4. PoPEx differently modulated the expression of activation markers (CD69, CD25, ICOS) and PD1 (inhibitory marker), depending on the dose and T-cell subsets. PoPEx (starting from 12.5 µg/mL) suppressed the production of Th1 (IFN-γ), Th17 (IL-17A, IL-17F, and IL-22), Th9 (IL-9), and proinflammatory cytokines (TNF-α and IL-6) in culture supernatants. Lower concentrations upregulated Th2 (IL-5 and IL-13) and Treg (IL-10) responses as well as CD4+CD25hiFoxp3+ cell frequency. Higher concentrations of PoPEx increased the frequency of IL-10- and TGF-ß-producing T-cells (much higher in the CD4+ subset). In conclusion, our study suggested for the first time complex immunoregulatory effects of PoPEx on T cells, which could assist in the suppression of chronic inflammatory and autoimmune diseases.

Mesenchymal Stromal Cells from Healthy and Inflamed Human Gingiva Respond Differently to Porphyromonas gingivalis.

Gingiva-Derived Mesenchymal Stromal Cells (GMSCs) have been shown to play an important role in periodontitis. However, how P. gingivalis, one of the key etiological agents of the disease, affects healthy (H)- and periodontitis (P)-GMSCs is unknown. To address this problem, we established 10 H-GMSC and 12 P-GMSC lines. No significant differences in morphology, differentiation into chondroblasts and adipocytes, expression of characteristic MSCS markers, including pericyte antigens NG2 and PDGFR, were observed between H- and P-GMSC lines. However, proliferation, cell size and osteogenic potential were higher in P-GMSCs, in contrast to their lower ability to suppress mononuclear cell proliferation. P. gingivalis up-regulated the mRNA expression of IL-6, IL-8, MCP-1, GRO-α, RANTES, TLR-2, HIF-1α, OPG, MMP-3, SDF-1, HGF and IP-10 in P-GMSCs, whereas only IL-6, MCP-1 and GRO-α were up-regulated in H-GMSCs. The expression of MCP-1, RANTES, IP-10 and HGF was significantly higher in P-GMSCs compared to H-GMSCs, but IDO1 was lower. No significant changes in the expression of TLR-3, TLR-4, TGF-ß, LAP, IGFBP4 and TIMP-1 were observed in both types of GMSCs. In conclusion, our results suggest that P-GMSCs retain their pro-inflammatory properties in culture, exhibit lower immunosuppressive potential than their healthy counterparts, and impaired regeneration-associated gene induction in culture. All these functions are potentiated significantly by P. gingivalis treatment.

Probiotic-mediated p38 MAPK immune signaling prolongs the survival of Caenorhabditis elegans exposed to pathogenic bacteria.

The host-microbiota cross-talk represents an important factor contributing to innate immune response and host resistance during infection. It has been shown that probiotic lactobacilli exhibit the ability to modulate innate immunity and enhance pathogen elimination. Here we showed that heat-inactivated probiotic strain Lactobacillus curvatus BGMK2-41 stimulates immune response and resistance of the Caenorhabditis elegans against Staphylococcus aureus and Pseudomonas aeruginosa. By employing qRT-PCR and western blot analysis we showed that heat-inactivated BGMK2-41 activated PMK-1/p38 MAPK immunity pathway which prolongs the survival of C. elegans exposed to pathogenic bacteria in nematode killing assays. The C. elegans pmk-1 mutant was used to demonstrate a mechanistic basis for the antimicrobial potential of BGMK2-41, showing that BGMK2-41 upregulated PMK-1/p38 MAPK dependent transcription of C-type lectins, lysozymes and tight junction protein CLC-1. Overall, this study suggests that PMK-1/p38 MAPK-dependent immune regulation by BGMK2-41 is essential for probiotic-mediated C. elegans protection against gram-positive and gram-negative bacteria and could be further explored for development of probiotics with the potential to increase resistance of the host towards pathogens.

Fecal microbiota composition associates with the capacity of human peripheral blood monocytes to differentiate into immunogenic dendritic cells in vitro.

Although promising for active immunization in cancer patients, dendritic cells (DCs) vaccines generated in vitro display high inter-individual variability in their immunogenicity, which mostly limits their therapeutic efficacy. Gut microbiota composition is a key emerging factor affecting individuals' immune responses, but it is unknown how it affects the variability of donors' precursor cells to differentiate into immunogenic DCs in vitro. By analyzing gut microbiota composition in 14 healthy donors, along with the phenotype and cytokines production by monocyte-derived DCs, we found significant correlations between immunogenic properties of DC and microbiota composition. Namely, donors who had higher α-diversity of gut microbiota and higher abundance of short-chain fatty acid (SCFAs) and SCFA-producing bacteria in feces, displayed lower expression of CD1a on immature (im)DC and higher expression of ILT-3, costimulatory molecules (CD86, CD40) proinflammatory cytokines (TNF-α, IL-6, IL-8) and IL-12p70/IL-10 ratio, all of which correlated with their lower maturation potential and immunogenicity upon stimulation with LPS/IFNγ, a well-known Th1 polarizing cocktail. In contrast, imDCs generated from donors with lower α-diversity and higher abundance of Bifidobacterium and Collinsella in feces displayed higher CD1a expression and higher potential to up-regulate CD86 and CD40, increase TNF-α, IL-6, IL-8 production, and IL-12p70/IL-10 ratio upon stimulation. These results emphasize the important role of gut microbiota on the capacity of donor precursor cells to differentiate into immunogenic DCs suitable for cancer therapy, which could be harnessed for improving the actual and future DC-based cancer therapies.

Host-commensal interaction promotes health and lifespan in Caenorhabditis elegans through the activation of HLH-30/TFEB-mediated autophagy.

Gut homeostasis is maintained by the close interaction between commensal intestinal microbiota and the host, affecting the most complex physiological processes, such as aging. Some commensal bacteria with the potential to promote healthy aging arise as attractive candidates for the development of pro-longevity probiotics. Here, we showed that heat-inactivated human commensal Lactobacillus fermentum BGHV110 (BGHV110) extends the lifespan of Caenorhabditis elegans and improves age-related physiological features, including locomotor function and lipid metabolism. Mechanistically, we found that BGHV110 promotes HLH-30/TFEB-dependent autophagy to delay aging, as longevity assurance was completely abolished in the mutant lacking HLH-30, a major autophagy regulator in C. elegans. Moreover, we observed that BGHV110 partially decreased the content of lipid droplets in an HLH-30-dependent manner and, at the same time, slightly increased mitochondrial activity. In summary, this study demonstrates that specific factors from commensal bacteria can be used to exploit HLH-30/TFEB-mediated autophagy in order to promote longevity and fitness of the host.

Reduced Expression of Autophagy Markers and Expansion of Myeloid-Derived Suppressor Cells Correlate With Poor T Cell Response in Severe COVID-19 Patients.

Widespread coronavirus disease (COVID)-19 is causing pneumonia, respiratory and multiorgan failure in susceptible individuals. Dysregulated immune response marks severe COVID-19, but the immunological mechanisms driving COVID-19 pathogenesis are still largely unknown, which is hampering the development of efficient treatments. Here we analyzed ~140 parameters of cellular and humoral immune response in peripheral blood of 41 COVID-19 patients and 16 age/gender-matched healthy donors by flow-cytometry, quantitative PCR, western blot and ELISA, followed by integrated correlation analyses with ~30 common clinical and laboratory parameters. We found that lymphocytopenia in severe COVID-19 patients (n=20) strongly affects T, NK and NKT cells, but not B cells and antibody production. Unlike increased activation of ICOS-1+ CD4+ T cells in mild COVID-19 patients (n=21), T cells in severe patients showed impaired activation, low IFN-γ production and high functional exhaustion, which correlated with significantly down-regulated HLA-DR expression in monocytes, dendritic cells and B cells. The latter phenomenon was followed by lower interferon responsive factor (IRF)-8 and autophagy-related genes expressions, and the expansion of myeloid derived suppressor cells (MDSC). Intriguingly, PD-L1-, ILT-3-, and IDO-1-expressing monocytic MDSC were the dominant producers of IL-6 and IL-10, which correlated with the increased inflammation and accumulation of regulatory B and T cell subsets in severe COVID-19 patients. Overall, down-regulated IRF-8 and autophagy-related genes expression, and the expansion of MDSC subsets could play critical roles in dysregulating T cell response in COVID-19, which could have large implications in diagnostics and design of novel therapeutics for this disease.