Rodney Hull

Modification by Ubiquitin-Like Proteins: Significance in Apoptosis and Autophagy Pathways

Ubiquitin-like proteins (Ubls) confer diverse functions on their target proteins. The modified proteins are involved in various biological processes, including DNA replication, signal transduction, cell cycle control, embryogenesis, cytoskeletal regulation, metabolism, stress response, homeostasis and mRNA processing. Modifiers such as SUMO, ATG12, ISG15, FAT10, URM1, and UFM have been shown to modify proteins thus conferring functions related to programmed cell death, autophagy and regulation of the immune system. Putative modifiers such as Domain With No Name (DWNN) have been identified in recent times but not fully characterized. In this review, we focus on cellular processes involving human Ubls and their targets. We review current progress in targeting these modifiers for drug design strategies.

Dung beetle database: comparison with other invertebrate transcriptomes

The dung beetle E. intermedius, a member of the highly diverse order, Coleoptera has immense economic benefits. It was estimated that insect ecological services in the United States amounted to some

Abnormalities in Alternative Splicing of Apoptotic Genes and Cardiovascular Diseases

60 billion in 2006 with dung beetles being major contributors. E. intermedius may be endowed with a robust immune system given its microbe-rich habitat. Dung beetles live on juice and microbes from the dung and are therefore, potential models for the study of infectious agents and ecological damage. The E. intermedius database is a web-based system for the genome and transcriptome of the dung beetle. The database will be expanded to include differentially expressed genes in response o various stresses especially infectious agents such as fungi, bacteria and viruses. Availability The dung beetle transcriptome database is freely available at http://flylab.wits.ac.za/

Glycolytic flux occurs in Drosophila melanogaster recovering from camptothecin treatment

Apoptosis is required for normal heart development in the embryo, but has also been shown to be an important factor in the occurrence of heart disease. Alternative splicing of apoptotic genes is currently emerging as a diagnostic and therapeutic target for heart disease. This review addresses the involvement of abnormalities in alternative splicing of apoptotic genes in cardiac disorders including cardiomyopathy, myocardial ischemia and heart failure. Many pro-apoptotic members of the Bcl-2 family have alternatively spliced isoforms that lack important active domains. These isoforms can play a negative regulatory role by binding to and inhibiting the pro-apoptotic forms. Alternative splicing is observed to be increased in various cardiovascular diseases with the level of alternate transcripts increasing elevated in diseased hearts compared to healthy subjects. In many cases these isoforms appear to be the underlying cause of the disease, while in others they may be induced in response to cardiovascular pathologies. Regardless of this, the detection of alternate splicing events in the heart can serve as useful diagnostic or prognostic tools, while those splicing events that seem to play a causative role in cardiovascular disease make attractive future drug targets.

Lifestyle and Host Defense Mechanisms of the Dung Beetle, Euoniticellus intermedius: The Toll Signaling Pathway

Camptothecin (CPT) and CPT-derived drugs are widely used against gynaecological and colorectal cancers. On account of their mechanism of action these drugs target rapidly dividing cells and may have an adverse effect on normal tissues. We sought to investigate their impact on normal cells by using Drosophila as a model. We investigated the possible involvement of Drosophila homologue of p53 (Dmp53) and a member of the retinoblastoma binding protein 6 family, known as Snama. On account of its molecular features and experimental evidence gleaned from mammalian studies we propose Snama as a candidate in Dmp53 regulation. We have used proteomics and core molecular biology techniques on embryos and on adult flies. We found that flies that recover from CPT treatment display a metabolic programme characterized by glycolytic flux, depletion of Dmp53 and increase of Snama transcripts. When we introduced methyl pyruvate in the diet to bypass the glycolytic pathway, we noticed differential expression of Dmp53 and Snama and improvement in reproduction and embryonic development. The development of embryos into the pupal stage was significantly improved to 40% (P=0.02) when CPT was given to mothers in combination with methyl pyruvate. This investigation highlights the importance of energy production mechanisms in cells that recover from chemotherapy and differences between the metabolic programmes used by recovering cells and those adopted by cancer cells.

Can the HIV-1 splicing machinery be targeted for drug discovery?

Abstract The dung beetle, Euoniticellus intermedius (Reiche) (Coleoptera: Scarabaeidae) is an important ecological and agricultural agent. Their main activity, the burying of dung, improves quality of the soil and reduces pests that could cause illness in animals. E. intermedius are therefore important for agriculture and for good maintenance of the environment, and are regarded as effective biological control agents for parasites of the gastrointestinal tract in livestock. The ability of E. intermedius to co-exist comfortably with many microorganisms, some of which are important human pathogens, stimulated our interest in its host defense strategies. The aim of this study was to investigate the Toll signaling pathway, which is strongly activated by fungi. Gene expression associated with fungal infection was analyzed by using 2-D gel electrophoresis and mass spectroscopy. Furthermore, the partial adult transcriptome was investigated for the presence of known immune response genes by using high-throughput sequencing and bioinformatics. The results presented here suggest that E. intermedius responds to fungal challenge via the Toll signaling pathway.

Current Immunotherapeutic Treatments in Colon Cancer

HIV-1 is able to express multiple protein types and isoforms from a single 9 kb mRNA transcript. These proteins are also expressed at particular stages of viral development, and this is achieved through the control of alternative splicing and the export of these transcripts from the nucleus. The nuclear export is controlled by the HIV protein Rev being required to transport incompletely spliced and partially spliced mRNA from the nucleus where they are normally retained. This implies a close relationship between the control of alternate splicing and the nuclear export of mRNA in the control of HIV-1 viral proliferation. This review discusses both the processes. The specificity and regulation of splicing in HIV-1 is controlled by the use of specific splice sites as well as exonic splicing enhancer and exonic splicing silencer sequences. The use of these silencer and enhancer sequences is dependent on the serine arginine family of proteins as well as the heterogeneous nuclear ribonucleoprotein family of proteins that bind to these sequences and increase or decrease splicing. Since alternative splicing is such a critical factor in viral development, it presents itself as a promising drug target. This review aims to discuss the inhibition of splicing, which would stall viral development, as an anti-HIV therapeutic strategy. In this review, the most recent knowledge of splicing in human immunodeficiency viral development and the latest therapeutic strategies targeting human immunodeficiency viral splicing are discussed.

The Role of MicroRNAs in Kidney Disease

The immune system is able to act against cancer cells and consequently these cells have developed a range of responses to evade or suppress the immune systems anticancer responses. The concept of cancer immunotherapy is based on techniques developed to restore or boost the ability of the immune system to recognize and target tumor cells. It is known that colon cancer does initiate an immune response and that this type of cancer initiates pathways and responses to evade or suppress the immune system. This chapter will discuss some of the dominant therapies being developed to treat colon cancer based on the concept of cancer immunotherapy. Cancer vaccines are based on the concept of providing the immune system with antigen targets derived from tumor-specific molecules, while monoclonal antibodies involve the development of antibodies specifically targeting proteins expressed on the surface of tumor cells. Antibodybased immunotherapy has further applications in the use of bispecific antibodies (BsAb), which are synthetic antibodies designed to be able to recognize two different antigens or epitopes and in this way can increase the immunoresponse and limit immune evasion observed in mono-targeted therapy. Immune checkpoint inhibitors target proteins that are responsible for keeping immune responses in check. Tumor cells overexpress these proteins in order to evade the immune response. Blocking these proteins will lead to an increased immune response against these cells. Cytokinebased immunotherapies involve the use of the immune systems’ own molecular messengers that are responsible for a robust immune response, to boost the antitumor response of the immune system. Oncolytic viral therapy is based on the use of viruses that selectively infect and replicate in cancer and associated endothelial cells and subsequently kills these cells. Adoptive immunotherapy involves the use of immune cells from the patient to be cultured and altered in the laboratory and then reintro‐ duced to boost the immune response. This is normally performed with T cells. Immunotherapy may be the next logical step in the development of an effective therapy for colon cancer and other cancers. The combination of these therapies with tradition‐ al chemotherapy or radiotherapy has shown promise in cancer treatment.

Translocator Protein (TSPO) as a Potential Biomarker in Human Cancers

MicroRNAs (miRNAs) are short noncoding RNAs that regulate pathophysiological processes that suppress gene expression by binding to messenger RNAs. These biomolecules can be used to study gene regulation and protein expression, which will allow better understanding of many biological processes such as cell cycle progression and apoptosis that control the fate of cells. Several pathways have also been implicated to be involved in kidney diseases such as Transforming Growth Factor-β, Mitogen-Activated Protein Kinase signaling, and Wnt signaling pathways. The discovery of miRNAs has provided new insights into kidney pathologies and may provide new innovative and effective therapeutic strategies. Research has demonstrated the role of miRNAs in a variety of kidney diseases including renal cell carcinoma, diabetic nephropathy, nephritic syndrome, renal fibrosis, lupus nephritis and acute pyelonephritis. MiRNAs are implicated as playing a role in these diseases due to their role in apoptosis, cell proliferation, differentiation and development. As miRNAs have been detected in a stable condition in different biological fluids, they have the potential to be tools to study the pathogenesis of human diseases with a great potential to be used in disease prognosis and diagnosis. The purpose of this review is to examine the role of miRNA in kidney disease.

Abnormalities in alternative splicing of angiogenesis-related genes and their role in HIV-related cancers

TSPO is a receptor involved in the regulation of cellular proliferation, apoptosis and mitochondrial functions. Previous studies showed that the expression of TSPO protein correlated positively with tumour malignancy and negatively with patient survival. The aim of this study was to determine the transcription of Tspo mRNA in various types of normal and cancer tissues. In situ hybridization was performed to localise the Tspo mRNA in various human normal and cancer tissues. The relative level of Tspo mRNA was quantified using fluorescent intensity and visual estimation of colorimetric staining. RT-PCR was used to confirm these mRNA levels in normal lung, lung cancer, liver cancer, and cervical cancer cell lines. There was a significant increase in the level of transcription in liver, prostate, kidney, and brain cancers while a significant decrease was observed in cancers of the colon and lung. Quantitative RT-PCR confirmed that the mRNA levels of Tspo are higher in a normal lung cell line than in a lung cancer cell line. An increase in the expression levels of Tspo mRNA is not necessarily a good diagnostic biomarker in most cancers with changes not being large enough to be significantly different when detected by in situ hybridisation.