Streptococcus pneumoniae is a leading cause of invasive bacterial infections. Although cigarette smoke is a risk factor known to be involved in the development of invasive pneumococcal disease, the underlying mechanism remains to be determined, primarily due to the lack of a clinically relevant animal model. A study published by PhD student Pamela Shen from Dr. Martin Stampfli’s lab, reported a novel model of nasal pneumococcal colonization in cigarette smoke-exposed mice, which was used to demonstrate, for the first time, that cigarette smoke predisposes mice to invasive pneumococcal infection and mortality. Mechanistically, the study showed that cigarette smoke impaired the response to S. pneumoniae by suppressing the expression of nasal inflammatory mediators, such as neutrophil-recruiting chemokines. Furthermore, they reported that the effects of cigarette smoke might be reversible, as smoking cessation during nasal colonization fully rescued mice from disease. Considering the fact that over 1 billion individuals smoke worldwide, this suggests that a considerable proportion of the global population is at increased risk, and the findings from this study may help guide future efforts to reduce the incidence of invasive pneumococcal disease. Read More
Dr. Jonathan Bramson’s group has recently received additional financial support from Mark Samuel and Kevin Sanford, both family members connected to the Samuel Family Foundation, to help bring their technology in cancer therapy from the lab into development for clinical use. The Samuel Family Foundation was founded in 2014, where $500, 000 were donated in an effort to help researchers at MIRC to develop a personalized immunotherapy cancer treatment. Just this month, the foundation has added another $250, 000, and Mark Samuel and Kevin Sanford have given an additional $200, 000 towards this investment in science. The Samuel Family Foundation supports work which is being carried out in the laboratory of Dr. Jonathan Bramson, and part of the funds also support immunological research trainees. Currently, Ksenia Bezverbnaya and Ken Mwawasi, MIRC trainees in the Bramson lab, are the two Samuel Family Scholars, however, more will be recruited. Family members associated with the foundation hope the gift will support bringing the early developmental work from the lab towards use in a clinical setting.
Colonization of Streptococcus pneumoniae within the upper respiratory tract (URT) of elderly individuals is a major concern, as it often results in the development of pneumonia, which can be deadly in this population. A study published by MIRC Masters’ student Netusha Thevaranjan, under the supervision of Dr. Dawn Bowdish, examined how aging can change the composition of the respiratory microbial community and consequently, impact bacterial colonization. Using a mouse model of pneumococcal colonization, the study characterized the composition of the URT microbiota in young, middle-aged, and old mice in both the naïve state, and throughout the course of nasopharyngeal colonization with S. pneumoniae. It was shown that the composition of the URT microbiota differs with age, and that colonization with S. pneumoniae in older mice disrupted pre-existing microbial communities.
Furthermore, the study demonstrated that there were several interspecies interactions between S. pneumoniae and resident microbes. In particular, Streptococcus interacted competitively with Staphylococcus and synergistically with Haemophilus. This work provides insight into how aging influences bacterial colonization, and understanding the relationship between these two factors can help create strategies to protect the elderly from age-associated infections and disease. Read More
A video produced by MIRC undergraduate student Yung Lee on Macrophage Evolution, featuring Dr. Dawn Bowdish and her lab, won a runner-up prize in the NSERC’s Science, Action! Video Contest. Congratulations to Yung and the Bowdish group!
Watch the video here!
Recently, a major discovery has been uncovered with the collaboration of Brian Lichty and Yonghong Wan from McMaster’s DeGroote School of Medicine. The study can lead to the development of vaccines for viruses like herpes, a common cold or even cancer. This research explains how our immune system detects a viral infection. Licthy have stated: "If the key immune system component identified in these studies is not triggered, then vaccination fails".
The group have focused in studying the cytosolic dna-mediated activation of the transcription factor IRF3 which is a key event in host antiviral responses. The findings have revealed a fundamental regulatory mechanism for the activation of IRF3 in the cytosolic DNA pathway. Nonetheless, the amazing effort by the lead author, Dr. Fuan Wang have revealed a groundbreaking story that impacts everyone who are infected by a virus, receiving a vaccination or fighting cancer
This study was recently published in "Nature Immunology". Further details can be found here.
Yung Lee, an undergraduate student in Dr. Charu Kaushic’s lab, was recently 1 of 3 second year undergraduate students awarded the Wilson Leadership Scholar Award. The Wilson Scholar program “recognizes Canada’s promising undergraduate students, cultivating their untapped potential and preparing them to serve as the nation’s next generation of leaders.” The award, which includes $50, 000 to cover educational expenses, along with admission to a leadership development program, is one of the highest valued undergraduate scholarships in Canada. The Kaushic lab is extremely proud of Yung’s continued excellence and achievements!
Yung Lee, a 2nd year undergraduate student, was recently awarded with the best overall poster presentation at the 29th annual Ontario Biology Day in Toronto. Competing against over 85 students from different universities across Ontario, Yung’s presented his research on examining the effects of female sex hormones on susceptibility to HSV-2 using a novel air-liquid interface culture. Yung’s accomplishment was especially impressive given that he was one of the youngest researchers at the conference. In addition to making his supervisor, Dr. Charu Kaushic, proud, Yung received a certificate and a $250 prize. Congratulations!
Congratulations to Yung Lee from Dr. Charu Kaushic’s lab and Jason Fan from Dr. Dawn Bowdish’s lab for being awarded the highly competitive IIDR Summer Student Fellowship. Yung and Jason are two of just ten undergraduate students selected for this fellowship, which is designed to support students working in the labs of IIDR members during their summer practicum.
Macrophages play a critical role in innate immunity by detecting, engulfing and destroying pathogenic bacteria and alerting neighbouring immune cells to join the fight against infection. They have many different receptors on their cell surface that allow them to carry out these important processes. A particular group of receptors called Scavenger Receptors are vital to this response. A recent study published in Immunology and Cell Biology by PhD student Kyle Novakowski from the laboratory of Dr. Dawn Bowdish has uncovered a mechanism by which a specific scavenger receptor contributes to macrophage-specific antibacterial immunity.
Scavenger Receptors are evolutionarily ancient and have evolved to recognize a wide array of pathogens by detecting ligands that are common across many pathogenic organisms. A particularly important Scavenger Receptor is Macrophage Receptor with Collagenous Structure, or MARCO. MARCO has been shown to significantly contribute to the clearance of Streptococcus pneumoniae colonization of the nose and in models of pneumococcal pneumonia. The NSERC-funded study took a unique approach to functionally characterizing how MARCO contributes to innate immunity by studying a naturally-occurring variant of the receptor. The study highlighted the importance of a particular domain of the receptor that is required for macrophages to bind and internalize ligands. The study also showed that the domain is necessary to enhance the pro-inflammatory response to pathogenic Streptococcus pneumoniae and can enhance cellular adhesion; both vital to proper macrophage functions.
To read the article, please click here.
PhD student Dessi Loukov in the lab of Dr. Dawn Bowdish, recently published a study showing that splenomegaly in old mice is a result of extramedullary hematopoiesis, and that this increased monopoiesis is driven by age-associated increase in TNF. The study compared changes in the microarchitecture and composition of the spleen in old and young mice and found that in old mice, there was an increase in the size and cellularity of the red pulp (the site of hematopoiesis of myeloid precursors). To study the role of TNF in the development of extramedullary hematopoiesis, they used TNF KO mice and found that these mice did not have increased extramedullary monopoiesis. Furthermore, they demonstrated that increased splenic myelopoiesis was a result of the aging microenvironment. This work suggests that strategies which aim to decrease the inflammatory microenvironment that comes with aging, would be effective in reducing inflammatory diseases propagated by cells of the myeloid lineage. Read More
In realization of his lifelong dream, recent MIRC graduate Dr. Victor Ferreira has been selected to compete on ‘Jeopardy!’, the popular, television trivia show. Victor completed his productive PhD in the laboratory of Dr. Charu Kaushic, where he focused on HIV replication in primary genital epithelial cells, and currently works as a medical researcher at the University Health Network in Toronto. Given that the Jeopardy producers recently announced that Canadians are no longer able to apply to be on the television show due to online privacy laws, he could be one of the last Canadians competing! Support Victor on Jeopardy this upcoming Friday (March 11) and watch as he makes MIRC proud.