Microbiologies
Abstract
TNFRSF13B encodes the "transmembrane-activator and CAML-interactor" (TACI) receptor, which drives plasma cell differentiation. Although TNFRSF13B supports host defense, dominant-negative TNFRSF13B alleles are common in humans and other species and only rarely associate with disease. We reasoned the high frequency of disruptive TNFRSF13B alleles reflects balancing selection, the loss of function conferring advantage in some settings. Testing that concept, we asked whether and how a common human dominant negative variant, TNFRSF13B A181E, imparts resistance to enteric pathogens. Mice engineered to express mono-allelic or bi-allelic A144E variants of tnrsf13B, corresponding to A181E exhibited striking resistance to pathogenicity and transmission of C. rodentium, a murine pathogen that models enterohemorrhagic E. coli, and resistance was principally owed to deficiency of natural IgA in the intestine. In wild type mice with gut IgA and in mutant mice fed IgA, binding of Ig induces expression of LEE encoded virulence genes, which confer pathogenicity and transmission. C. rodentium and probably some other enteric organisms thus appropriated binding of otherwise protective antibodies to signal induction of the virulence program and the high prevalence of TNFRSF13B dominant negative variants thus reflects balancing selection.
Authors
Jeffrey L. Platt, Mayara Garcia de Mattos Barbosa, Daniel Huynh, Adam R. Lefferts, Juhi Katta, Cyra Kharas, Peter L. Freddolino, Christine Marie Bassis, Christiane E. Wobus, Raif Geha, Richard J. Bram, Gabriel Nunez, Nobuhiko Kamada, Marilia Cascalho
Abstract
Chagas disease is caused by infection with the protozoan parasite Trypanosoma cruzi (T. cruzi), an intracellular pathogen that causes significant morbidity and death among millions in the Americas from Canada to Argentina. Current therapy involves oral administration of the nitroimidazole benznidazole (BNZ), which has serious side effects that often necessitate cessation of treatment. To both avoid off-target side effects and reduce the necessary dosage of BNZ, we packaged the drug within poly(ethylene glycol)-block-poly(propylene sulfide) polymersomes (BNZ-PSs). We show that these vesicular nanocarriers enhanced intracellular delivery to phagocytic cells and tested this formulation in a mouse model of T. cruzi infection. BNZ-PS is not only nontoxic but also significantly more potent than free BNZ, effectively reducing parasitemia, intracellular infection, and tissue parasitosis at a 466-fold lower dose of BNZ. We conclude that BNZ-PS was superior to BNZ for treatment of T. cruzi infection in mice and that further modifications of this nanocarrier formulation could lead to a wide range of custom controlled delivery applications for improved treatment of Chagas disease in humans.
Authors
Xiaomo Li, Sijia Yi, Débora B. Scariot, Santiago J. Martinez, Ben A. Falk, Cheryl L. Olson, Patricia S. Romano, Evan A. Scott, David M. Engman
Abstract
Gut microbe–derived metabolites influence human physiology and disease. However, establishing mechanistic links between gut microbial metabolites and disease pathogenesis in animal models remains challenging. The major route of absorption for microbe-derived small molecules is venous drainage via the portal vein to the liver. In the event of presystemic hepatic metabolism, the route of metabolite administration becomes critical. To our knowledge, we describe here a novel portal vein cannulation technique using a s.c. implanted osmotic pump to achieve continuous portal vein infusion in mice. We first administered the microbial metabolite trimethylamine (TMA) over 4 weeks, during which increased peripheral plasma levels of TMA and its host liver-derived cometabolite, trimethylamine-N-oxide, were observed when compared with a vehicle control. Next, 4-hydroxyphenylacetic acid (4-HPAA), a microbial metabolite that undergoes extensive presystemic hepatic metabolism, was administered intraportally to examine effects on hepatic gene expression. As expected, hepatic levels of 4-HPAA were elevated when compared with the control group while peripheral plasma 4-HPAA levels remained the same. Moreover, significant changes in the hepatic transcriptome were revealed by an unbiased RNA-Seq approach. Collectively, to our knowledge this work describes a novel method for administering gut microbe–derived metabolites via the portal vein, mimicking their physiologic delivery in vivo.
Authors
Danny Orabi, Lucas J. Osborn, Kevin Fung, William Massey, Anthony J. Horak III, Federico Aucejo, Ibrahim Choucair, Beckey DeLucia, Zeneng Wang, Jan Claesen, J. Mark Brown
Abstract
The drive to withstand environmental stresses and defend against invasion is a universal trait extant in all forms of life. While numerous canonical signaling cascades have been characterized in detail, it remains unclear how these pathways interface to generate coordinated responses to diverse stimuli. To dissect these connections, we follow heparanase (HPSE), a protein best known for its endoglycosidic activity at the extracellular matrix but recently recognized to drive various forms of late stage disease through unknown mechanisms. Using herpes simplex virus-1 (HSV-1) infection as a model cellular perturbation, we demonstrate that HPSE acts beyond its established enzymatic role to restrict multiple forms of cell-intrinsic defense and facilitate host cell reprogramming by the invading pathogen. We reveal that cells devoid of HPSE are innately resistant to infection and counteract viral takeover through multiple amplified defense mechanisms. With a unique grasp of the fundamental processes of transcriptional regulation and cell death, HPSE represents a potent cellular intersection with broad therapeutic potential.
Authors
Alex Agelidis, Benjamin A. Turturice, Rahul K. Suryawanshi, Tejabhiram Yadavalli, Dinesh Jaishankar, Joshua Ames, James Hopkins, Lulia Koujah, Chandrashekhar D. Patil, Satvik R. Hadigal, Evan J. Kyzar, Anaamika Campeau, Jacob M. Wozniak, David J. Gonzalez, Israel Vlodavsky, Jin-ping Li, David L. Perkins, Patricia W. Finn, Deepak Shukla
Abstract
BACKGROUND Identifying factors conferring responses to therapy in cancer is critical to select the best treatment for patients. For immune checkpoint inhibition (ICI) therapy, mounting evidence suggests that the gut microbiome can determine patient treatment outcomes. However, the extent to which gut microbial features are applicable across different patient cohorts has not been extensively explored.METHODS We performed a meta-analysis of 4 published shotgun metagenomic studies (Ntot = 130 patients) investigating differential microbiome composition and imputed metabolic function between responders and nonresponders to ICI.RESULTS Our analysis identified both known microbial features enriched in responders, such as Faecalibacterium as the prevailing taxa, as well as additional features, including overrepresentation of Barnesiella intestinihominis and the components of vitamin B metabolism. A classifier designed to predict responders based on these features identified responders in an independent cohort of 27 patients with the area under the receiver operating characteristic curve of 0.625 (95% CI: 0.348–0.899) and was predictive of prognosis (HR = 0.35, P = 0.081).CONCLUSION These results suggest the existence of a fecal microbiome signature inherent across responders that may be exploited for diagnostic or therapeutic purposes.FUNDING This work was funded by the Knut and Alice Wallenberg Foundation, BioGaia AB, and Cancerfonden.
Authors
Angelo Limeta, Boyang Ji, Max Levin, Francesco Gatto, Jens Nielsen
Abstract
Infections caused by multi-drug resistant Staphylococcus aureus, especially MRSA, are responsible for high mortality and morbidity worldwide. Resistant lineages were previously confined to hospitals, but are now also causing infections among healthy individuals in the community. It is therefore imperative to explore therapeutic avenues that are less prone to raise drug resistance compared to today’s antibiotics. An opportunity to achieve this ambitious goal could be provided by targeted antimicrobial photodynamic therapy (aPDT), which relies on the combination of a bacteria-specific targeting agent and light-induced generation of reactive oxygen species by an appropriate photosensitizer. Here we conjugated the near-infrared photosensitizer IRDye700DX to a fully human monoclonal antibody, specific for the invariantly expressed staphylococcal antigen IsaA. The resulting immunoconjugate 1D9-700DX was characterized biochemically and in preclinical infection models. As demonstrated in vitro, in vivo, and in a human post-mortem orthopedic implant infection model, targeted aPDT with 1D9-700DX is highly effective. Importantly, combined with the non-toxic aPDT-enhancing agent potassium iodide, 1D9-700DX overcomes the antioxidant properties of human plasma and fully eradicates high titers of MRSA. We show that the developed immunoconjugate 1D9-700DX targets MRSA and kills it upon illumination with red light, without causing collateral damage to human cells.
Authors
Mafalda Bispo, Andrea Anaya-Sanchez, Sabrina Suhani, Elisa J.M. Raineri, Marina López-Álvarez, Marjolein Heuker, Wiktor Szymański, Francisco Romero Pastrana, Girbe Buist, Alexander R. Horswill, Kevin P. Francis, Gooitzen M. van Dam, Marleen van Oosten, Jan Maarten van Dijl
Abstract
Severe burn injury induces gut barrier dysfunction and subsequently a profound systemic inflammatory response. In the present study, we examined the role of the small intestinal brush border enzyme, intestinal alkaline phosphatase (IAP), in preserving gut barrier function and preventing systemic inflammation after burn wound infection in mice. Mice were subjected to a 30% total body surface area dorsal burn with or without intradermal injection of Pseudomonas aeruginosa. Mice were gavaged with 2000 units of IAP or vehicle at 3 and 12 hours after the insult. We found that both endogenously produced and exogenously supplemented IAP significantly reduced gut barrier damage, decreased bacterial translocation to the systemic organs, attenuated systemic inflammation, and improved survival in this burn wound infection model. IAP attenuated liver inflammation and reduced the proinflammatory characteristics of portal serum. Furthermore, we found that intestinal luminal contents of burn wound–infected mice negatively impacted the intestinal epithelial integrity compared with luminal contents of control mice and that IAP supplementation preserved monolayer integrity. These results indicate that oral IAP therapy may represent an approach to preserving gut barrier function, blocking proinflammatory triggers from entering the portal system, preventing gut-induced systemic inflammation, and improving survival after severe burn injuries.
Authors
Fatemeh Adiliaghdam, Paul Cavallaro, Vidisha Mohad, Marianna Almpani, Florian Kühn, Mohammad Hadi Gharedaghi, Mehran Najibi, Laurence G. Rahme, Richard A. Hodin
Abstract
ABSTRACTWith the effectiveness of antimicrobials declining as antimicrobial resistance continues to threaten public health, we must look to alternative strategies for the treatment of infections. In this study, we investigated an innovative ‘drug-free’ dual-wavelength irradiation approach that combines two wavelengths of light, 460 nm and 405 nm, against methicillin resistant Staphylococcus aureus (MRSA). MRSA was initially irradiated with 460 nm light (90-360 J/cm2) and subsequently irradiated with aliquots of 405 nm light (54-324 J/cm2). For in vivo studies, mouse skin was abraded and infected with approximately 107 CFU of MRSA and incubated for 3 hours before irradiating with 460 nm (360 J/cm2) and 405 nm (342 J/cm2). Naïve mouse skin was also irradiated to investigate apoptosis. We found that staphyloxanthin, the carotenoid pigment in MRSA cells, promoted resistance to the antimicrobial effects of 405 nm light. In addition, we found that the photolytic effect of 460 nm light on staphyloxanthin attenuated resistance of MRSA to 405 nm light inactivation. Irradiation of 460 nm alone did not elicit any antimicrobial effect on MRSA. In a proof-of-principle mouse skin abrasion infection model, we observed significant inactivation of MRSA by the dual-wavelength irradiation approach. However, when either wavelength of light was administered alone, no significant decrease in bacterial viability was observed. Moreover, exposure of the dual-wavelength irradiation to naïve mouse skin did not result in any visible apoptosis.In conclusion, dual-wavelength irradiation strategy may offer an innovative, effective and safe approach for the treatment of skin infections caused by MRSA.
Authors
Leon G. Leanse, Xueping Sharon Goh, Ji-Xin Cheng, David Hooper, Tianhong Dai
Abstract
Inflammation is a major risk factor of morbidity and mortality in older adults. Although its precise etiology is unknown, low-grade inflammation in older adults is commonly associated with increased intestinal epithelial permeability (leaky gut) and abnormal (dysbiotic) gut microbiota. The increasing older population and lack of treatments to reduce aging-related microbiota dysbiosis, leaky gut and inflammation culminates on a rise in aging-related comorbidities, constituting a significant public health concern. Here we demonstrate that a human-origin probiotic cocktail containing 5-Lactobacillus and 5 Enterococcus strains isolated from healthy infant’s gut prevents high-fat diet (HFD)-induced microbiota dysbiosis, leaky gut, inflammation, metabolic dysfunctions and physical function decline in older mice. Probiotic-modulated gut microbiota primarily reduced leaky gut by increasing tight junctions, which in turn reduced inflammation. Mechanistically, probiotics modulated microbiota in a way to increases bile salt hydrolase activity, which in turn increased taurine abundance in the gut that stimulated tight junctions and suppressed gut leakiness. Further, in Caenorhabditis elegans, taurine increased life span, reduced adiposity and leaky gut, and enhanced physical function. The results suggest that such probiotic therapies could prevent or treat aging-related leaky gut and inflammation in elderly.
Authors
Shokouh Ahmadi, Shaohua Wang, Ravinder Nagpal, Bo Wang, Shalini Jain, Atefeh Razazan, Sidharth P. Mishra, Xuewei Zhu, Zhan Wang, Kylie Kavanagh, Hariom Yadav
Abstract
Relatively little is known about interactions between the airway microbiome and airway host transcriptome in asthma. Since asthma affects and is affected by the entire airway, studying the upper (e.g., nasal) and lower (e.g., bronchial) airways together represents a powerful approach to understanding asthma. Here, we performed a systematic, integrative study of the nasal and bronchial microbiomes and nasal and bronchial host transcriptomes of children with severe persistent asthma and healthy controls. We found that (a) the microbiomes and host transcriptomes of asthmatic children are each distinct by site (nasal versus bronchial); (b) among asthmatic children, Moraxella and Alloiococcus are hub genera in the nasal microbiome, while there are no hubs among bronchial genera; (c) bronchial Actinomyces is negatively associated with bronchial genes for inflammation, suggesting Actinomyces may be protective; (d) compared with healthy children, asthmatic children express more nasal genes for ciliary function and harbor more nasal Streptococcus; and (e) nasal genera such as Corynebacterium are negatively associated with significantly more nasal genes for inflammation in healthy versus asthmatic children, suggesting a potentially stronger protective role for such nasal genera in healthy versus asthmatic children. Our systematic, integrative study provides a window into host-microbiome associations in asthma.
Authors
Yoojin Chun, Anh Do, Galina Grishina, Alexander Grishin, Gang Fang, Samantha Rose, Chantal Spencer, Alfin Vicencio, Eric Schadt, Supinda Bunyavanich
No posts were found with this tag.
