Project description:Among the most central questions in Leishmania research is why some species remain in the skin dermis at the site of infection by the sand fly vector whereas other species migrate to visceral organs where they cause fatal visceral leishmaniasis. Although L. donovani is the species typically responsible for visceral leishmaniasis, an atypical L. donovani strain is the etiologic agent for cutaneous leishmaniasis in Sri Lanka. To identify molecular determinants for visceral disease, we have analysed the phenotype and genotype of two L. donovani clinical isolates from Sri Lanka where one isolate was derived from a cutaneous leishmaniasis patient (CL) and the other from a visceral leishmaniasis patient (VL). These isolates cause dramatically different pathology when introduced into mice; notably the CL isolate has lost the ability to survive in visceral organs while the VL isolate was highly virulent in visceral organs of BALB/c mice. Whole genome sequencing of the CL and VL isolates revealed that these genomes were very similar as there were no gene deletions and few individual gene amplifications. Indels resulting in frame shifts and loss/gain of stop codons resulted in 13 distinct pseudogenes present in each of the CL and VL isolates. There were 154 non-synonymous SNPs specific to the CL isolate and 193 non-synonymous SNPs specific to the VL isolate. Genome wide gene expression analysis revealed several transcript level differences, including the A2 virulence gene resulting in higher expression of A2 proteins in the VL isolate than in the CL isolate. Genotypic variations relevant to pathology and tropism in Leishmania can be interrogated by reverse genetics. Experimentally increasing A2 expression in the CL isolate through gene transfer significantly increased itM-bM-^@M-^Ys ability to survive in the spleen of BALB/c mice and conversely, down-regulating A2 expression in the VL isolate abrogated attenuated its survival in BALB/c mice. These observations reveal that there are relatively few genetic differences between the CL and VL isolates apart from the A2 genes, but collectively these have profound effects on human disease and experimentally infected mice. 6 Samples in total, 3 each from VL and CL causing isolates were analyzed by Splice Leader RNASeq. These three samples from each of the isolates were grown to form one of the following three lifestages, Promastigotes, Macrophage derived Amastigotes, Axenic Amastigotes.

Project description:Among the most central questions in Leishmania research is why some species remain in the skin dermis at the site of infection by the sand fly vector whereas other species migrate to visceral organs where they cause fatal visceral leishmaniasis. Although L. donovani is the species typically responsible for visceral leishmaniasis, an atypical L. donovani strain is the etiologic agent for cutaneous leishmaniasis in Sri Lanka. To identify molecular determinants for visceral disease, we have analysed the phenotype and genotype of two L. donovani clinical isolates from Sri Lanka where one isolate was derived from a cutaneous leishmaniasis patient (CL) and the other from a visceral leishmaniasis patient (VL). These isolates cause dramatically different pathology when introduced into mice; notably the CL isolate has lost the ability to survive in visceral organs while the VL isolate was highly virulent in visceral organs of BALB/c mice. Whole genome sequencing of the CL and VL isolates revealed that these genomes were very similar as there were no gene deletions and few individual gene amplifications. Indels resulting in frame shifts and loss/gain of stop codons resulted in 13 distinct pseudogenes present in each of the CL and VL isolates. There were 154 non-synonymous SNPs specific to the CL isolate and 193 non-synonymous SNPs specific to the VL isolate. Genome wide gene expression analysis revealed several transcript level differences, including the A2 virulence gene resulting in higher expression of A2 proteins in the VL isolate than in the CL isolate. Genotypic variations relevant to pathology and tropism in Leishmania can be interrogated by reverse genetics. Experimentally increasing A2 expression in the CL isolate through gene transfer significantly increased it’s ability to survive in the spleen of BALB/c mice and conversely, down-regulating A2 expression in the VL isolate abrogated attenuated its survival in BALB/c mice. These observations reveal that there are relatively few genetic differences between the CL and VL isolates apart from the A2 genes, but collectively these have profound effects on human disease and experimentally infected mice.

Project description:Background: Oral squamous cell carcinoma (OSCC) is a major world health problem with over 400,000 new cases diagnosed annually. Despite advances in surgery and chemo-radiotherapy, the 5 year survival has remained roughly constant at approximately 50% for several decades. The disease is characterized by both clinical and genetic heterogeneity, so elucidating the molecular basis of this heterogeneity would have significant clinical implications. It is well recognized that OSCCs from Asia that are associated with betel quid chewing are phenotypically distinct from those from the West that are predominantly caused by smoking/drinking, but the genetic basis of these differences are largely unknown. The aim of this study is to examine the most related genetic factors, carcinogenic related pathways, and molecular processes that might be responsible for the phenotypic heterogeneity of OSCC between UK and Sri Lankan population groups. Methods: We have compared the gene expression profiles of OSCCs and normal oral mucosal tissues from both Sri Lankan and UK individuals using Affymetrix gene expression arrays. Results: The gene expression profiles of UK and Sri Lankan OSCC are similar in many respects to other oral cancer expression profiles reported in the literature and were mainly similar to each other. However, genes involved in tumor invasion, metastasis and recurrence were more obviously associated with UK tumors as opposed to those from Sri Lanka. Interestingly, Ingenuity Pathway Analysis (IPA) revealed a highly activated cell-mediated immune response in both Sri Lankan normal and tumor samples relative to UK cohorts, which may, in part, explain the less aggressive behavior of these betel quid-induced OSCCs. Conclusion: The development of OSCCs in both UK and Sri Lankan populations appears largely mediated by similar biological pathways despite the differences related to race, ethnicity, lifestyle, and/or exposure to environmental carcinogens. However, IPA revealed a highly activated M-bM-^@M-^\Cell-mediated Immune ResponseM-bM-^@M-^] in Sri Lankan normal and tumor samples relative to UK cohorts. It seems likely, therefore, that any future attempts to personalize treatment for OSCC patients will need to be different in Western and Asian countries to reflect differences in gene expression and the immune status of the patients. All biopsy specimens of OSCC and normal oral mucosa were harvested with appropriate ethical approval and informed consent of individual patients (LREC 0769). Identical protocols for tissue collection and processing were used in both countries. OSCC samples were obtained from sequential incident cases treated by a single consultant surgeon from 2001 to 2004 at University Hospital of Birmingham, NHS Foundation Trust, Birmingham, UK, and Kandy General Hospital, Kandy, Sri Lanka. A total of 21 UK and 27 Sri Lankan samples yielded RNA of sufficient quality and quantity for microarray analysis. In addition, 8 normal oral mucosa specimens (five samples from UK & three samples from Sri Lankan population) were also profiled. All normal samples were from non-smokers, who did not chew betel quid and did not consume in excess of the national recommended weekly gender allowance of alcohol. Normal samples were taken from individuals with no history of cancer and had no first degree relatives with a history of cancer.

Project description:Background: Oral squamous cell carcinoma (OSCC) is a major world health problem with over 400,000 new cases diagnosed annually. Despite advances in surgery and chemo-radiotherapy, the 5 year survival has remained roughly constant at approximately 50% for several decades. The disease is characterized by both clinical and genetic heterogeneity, so elucidating the molecular basis of this heterogeneity would have significant clinical implications. It is well recognized that OSCCs from Asia that are associated with betel quid chewing are phenotypically distinct from those from the West that are predominantly caused by smoking/drinking, but the genetic basis of these differences are largely unknown. The aim of this study is to examine the most related genetic factors, carcinogenic related pathways, and molecular processes that might be responsible for the phenotypic heterogeneity of OSCC between UK and Sri Lankan population groups. Methods: We have compared the gene expression profiles of OSCCs and normal oral mucosal tissues from both Sri Lankan and UK individuals using Affymetrix gene expression arrays. Results: The gene expression profiles of UK and Sri Lankan OSCC are similar in many respects to other oral cancer expression profiles reported in the literature and were mainly similar to each other. However, genes involved in tumor invasion, metastasis and recurrence were more obviously associated with UK tumors as opposed to those from Sri Lanka. Interestingly, Ingenuity Pathway Analysis (IPA) revealed a highly activated cell-mediated immune response in both Sri Lankan normal and tumor samples relative to UK cohorts, which may, in part, explain the less aggressive behavior of these betel quid-induced OSCCs. Conclusion: The development of OSCCs in both UK and Sri Lankan populations appears largely mediated by similar biological pathways despite the differences related to race, ethnicity, lifestyle, and/or exposure to environmental carcinogens. However, IPA revealed a highly activated “Cell-mediated Immune Response” in Sri Lankan normal and tumor samples relative to UK cohorts. It seems likely, therefore, that any future attempts to personalize treatment for OSCC patients will need to be different in Western and Asian countries to reflect differences in gene expression and the immune status of the patients.

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