Telomere elongation in the gut extends zebrafish lifespan

Telomere shortening is a hallmark of aging and is counteracted by telomerase. The gut is one of the earliest organs to exhibit short telomeres and tissue dysfunction during normal zebrafish aging. This is recapitulated in prematurely aged telomerase mutants (tert-/-). Here, we show that gut-specific telomerase activity in tert-/- zebrafish prevents premature aging. Induction of telomerase rescues gut senescence and low cell proliferation to wild-type levels, while restoring gut tissue integrity, inflammation, and age-dependent gut microbiota dysbiosis. Remarkably, averting gut dysfunction results in a systemic beneficial impact. Gut-specific telomerase activity rescues premature aging markers in remote organs, such as the reproductive (testes) and hematopoietic (kidney marrow) systems. Functionally, it also rescues age-dependent loss of male fertility and testes atrophy. Finally, we show that gut-specific telomerase activity increases the lifespan of telomerase mutants. Our work demonstrates that delaying telomere shortening in the gut is sufficient to systemically counteract aging in zebrafish.

Missense Mutations in Desmoplakin Plakin Repeat Domains Have Dramatic Effects on Domain Structure and Function

Plakin repeat domains (PRDs) are globular modules that mediate the interaction of plakin proteins with the intermediate filament (IF) cytoskeleton. These associations are vital for maintaining tissue integrity in cardiac muscle and epithelial tissues. PRDs are subject to mutations that give rise to cardiomyopathies such as arrhythmogenic right ventricular cardiomyopathy, characterised by ventricular arrhythmias and associated with an increased risk of sudden heart failure, and skin blistering diseases. Herein, we have examined the functional and structural effects of 12 disease-linked missense mutations, identified from the human gene mutation database, on the PRDs of the desmosomal protein desmoplakin. Five mutations (G2056R and E2193K in PRD-A, G2338R and G2375R in PRD-B and G2647D in PRD-C) rendered their respective PRD proteins either fully or partially insoluble following expression in bacterial cells. Each of the residues affected are conserved across plakin family members, inferring a crucial role in maintaining the structural integrity of the PRD. In transfected HeLa cells, the mutation G2375R adversely affected the targeting of a desmoplakin C-terminal construct containing all three PRDs to vimentin IFs. The deletion of PRD-B and PRD-C from the construct compromised its targeting to vimentin. Bioinformatic and structural modelling approaches provided multiple mechanisms by which the disease-causing mutations could potentially destabilise PRD structure and compromise cytoskeletal linkages. Overall, our data highlight potential molecular mechanisms underlying pathogenic missense mutations and could pave the way for informing novel curative interventions targeting cardiomyopathies and skin blistering disorders.

Effects of Different Probiotic Strains B. Lactis, L. Rhamnosus and L. Reuteri on Brain-Intestinal Axis Immunomodulation in an Endotoxin-Induced Inflammation

Aim: The study evaluated the effects of supplementation with three different probiotic strains B. lactis (LACT GBTM), L. rhamnosus (RHAM GBTM) and L. reuteri (REUT GBTM) on brain-intestinal immunomodulation in an animal model of LPS-induced inflammation. Methods: 50 mice Balb/C were distributed into five groups: Control; lipopolysaccharide (LPS); LPS + B. lactis (LACT GBTM); LPS + L. rhamnosus (RHAM GBTM); LPS + L. reuteri (REUT GBTM). The animals were supplemented with their respective probiotic microorganisms daily, for 30 days, at a concentration of 1x109 CFU/animal/day. After 30 days of supplementation, animals received the inflammatory insult by LPS (15mg/kg). Behavioral tests, oxidative stress and inflammation were performed, as well as gut and brain histology. Results: In the behavioral test, LPS+ B. lactis group was less anxious than the other groups. Serum interleukin IL-1β and IL-6 levels increased in all groups that received the LPS insult and there was a reduction in inflammation in the supplemented groups when compared to the LPS group in brain and gut. A reduction in myeloperoxidase activity and oxidative stress in groups supplemented with probiotics. Intestine histological analysis, damage to tissue integrity in the LPS group and preservation of integrity in the supplemented animals. In the brain, infiltrates of perivascular inflammatory cells can be seen in the LPS group. Conclusion: The three probiotic studies showed efficient immunomodulating activity and ensured integrity of the intestinal barrier function, even after the severe insult by LPS. These results show the important role of probiotics in the gut-brain axis.

The Cytotoxic Necrotizing Factors (CNFs)—A Family of Rho GTPase-Activating Bacterial Exotoxins

The cytotoxic necrotizing factors (CNFs) are a family of Rho GTPase-activating single-chain exotoxins that are produced by several Gram-negative pathogenic bacteria. Due to the pleiotropic activities of the targeted Rho GTPases, the CNFs trigger multiple signaling pathways and host cell processes with diverse functional consequences. They influence cytokinesis, tissue integrity, cell barriers, and cell death, as well as the induction of inflammatory and immune cell responses. This has an enormous influence on host–pathogen interactions and the severity of the infection. The present review provides a comprehensive insight into our current knowledge of the modular structure, cell entry mechanisms, and the mode of action of this class of toxins, and describes their influence on the cell, tissue/organ, and systems levels. In addition to their toxic functions, possibilities for their use as drug delivery tool and for therapeutic applications against important illnesses, including nervous system diseases and cancer, have also been identified and are discussed.

Effects of Different Probiotic Strains B. Lactis, L. Rhamnosus and L. Reuteri on Brain-Intestinal Axis Immunomodulation in an Endotoxin-Induced Inflammation

Aim: The study evaluated the effects of supplementation with three different probiotic strains B. lactis (LACT GBTM), L. rhamnosus (RHAM GBTM) and L. reuteri (REUT GBTM) on brain-intestinal immunomodulation in an animal model of LPS-induced inflammation. Methods: 50 mice Balb/C were distributed into five groups: Control; lipopolysaccharide (LPS); LPS + B. lactis (LACT GBTM); LPS + L. rhamnosus (RHAM GBTM); LPS + L. reuteri (REUT GBTM). The animals were supplemented with their respective probiotic microorganisms daily, for 30 days, at a concentration of 1x109 CFU/animal/day. After 30 days of supplementation, animals received the inflammatory insult by LPS (15mg/kg). Behavioral tests, oxidative stress and inflammation were performed, as well as gut and brain histology. Results: In the behavioral test, LPS+ B. lactis group was less anxious than the other groups. Serum interleukin IL-1β and IL-6 levels increased in all groups that received the LPS insult and there was a reduction in inflammation in the supplemented groups when compared to the LPS group in brain and gut. A reduction in myeloperoxidase activity and oxidative stress in groups supplemented with probiotics. Intestine histological analysis, damage to tissue integrity in the LPS group and preservation of integrity in the supplemented animals. In the brain, infiltrates of perivascular inflammatory cells can be seen in the LPS group. Conclusion: The three probiotic studies showed efficient immunomodulating activity and ensured integrity of the intestinal barrier function, even after the severe insult by LPS. These results show the important role of probiotics in the gut-brain axis.

Disease Tolerance during Viral-Bacterial Co-Infections

Disease tolerance has emerged as an alternative way, in addition to host resistance, to survive viral-bacterial co-infections. Disease tolerance plays an important role not in reducing pathogen burden, but in maintaining tissue integrity and controlling organ damage. A common co-infection is the synergy observed between influenza virus and Streptococcus pneumoniae that results in superinfection and lethality. Several host cytokines and cells have shown promise in promoting tissue protection and damage control while others induce severe immunopathology leading to high levels of morbidity and mortality. The focus of this review is to describe the host cytokines and innate immune cells that mediate disease tolerance and lead to a return to host homeostasis and ultimately, survival during viral-bacterial co-infection.

Electron microscopic and pathological changes of lung cancer after intratumoral injection of sodium bicarbonate

Background: Lung cancer can be treated with surgery, chemotherapy, radiation therapy, targeted therapy and palliative care. Palliative therapy is applied for inoperable lung cancer as it induces tumour necrosis. PH of tumour tissue is acidic; application of sodium bicarbonate (SB) into lung cancer locally via bronchoscopy can change its core pH, which may lead to tumour destruction. We aimed to study the ultrastructural characteristics of lung cancer and to assess the destructive effects of sodium bicarbonate 8.4% local injection on tumour tissue integrity by light and electron microscopies. Methods: This study was conducted on 21 patients with central bronchial carcinoma diagnosed according to WHO classification 2015. Three bronchoscopic biopsies were taken; two biopsies before and one after injection of sodium bicarbonate 8.4% solution of 20 ml via transbronchial needle. All biopsies were examined by both light and electron microscopes. The first biopsy was examined to diagnose the tumour morphologically with and without immunostaining. Second and third biopsies were taken before and after SB 8.4% injection to compare pathological changes in tumour tissue integrity as well as cellular ultra-structures. Different lung cancer pathological types were included in the study. Results: Tumour tissue integrity and pathological changes were examined in biopsies before and after injection of sodium bicarbonate 8.4%. Extensive necrosis in all cell types of lung cancer was seen after injection of SB; this important finding was delineated by both light and electron microscopies. Conclusion: Preliminary ultrastructural study of small biopsy of lung tumor has a complementary role to both morphological and immunohistochemical studies. Local injection of sodium bicarbonate into lung cancer induces extensive necrosis that may reflect its important therapeutic role in lung cancer.

Initial Angiotensin Receptor Blocker Response in Young Marfan Patients Decreases After 3 Years of Treatment

Marfan syndrome is caused by mutations of the fibrillin-1 gene, which weakens the connective tissue integrity. Since 2003, bioavailability regulations of TGF-ß through fibrillin alterations have been presumed of being the culprit mechanisms for aortic aneurysm development. We present the analysis of our single-center Marfan children and adolescents cohort to assess the influence of age, sex, degree of cardiovascular involvement and dosage on losartan effectivity. This prospective longitudinal registered echocardiographical investigation (EudraCT 2009-016139-36) of 49 patients with an average follow-up of 72 months focused on aortic root z-scores, elasticity, and yearly progression rates. The 33 patients under medication with losartan showed an aortic root z-score reduction during the first 36 months compared to 22 patients without medication presenting constant mild progression. Yet, results diminished under losartan thereafter, adding up to similar progressions over 72 months in both groups (0.07 ± 0.10/year versus 0.04 ± 0.11/year). Although male patients exhibited higher root z-scores, progression with and without medication was comparable to females and not age-dependent. In conclusion, losartan evoked a significant aortic root z-score regression in young Marfan patients over the first 3 years, but this effect mitigated thereafter. The initial improvement concurred with ameliorated elasticity; lower stiffness levels predicted better clinical outcome, but likewise only up to 36 months. Sex differences in dilatation severity were observed but neither age nor sex had significant influence on progression rates. Losartan dosages were gradually increased in more severely affected patients and provided an equal rate of root progression over 72 months in comparison to patients under losartan treatment with lesser baseline dilatation severity.