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Durante o ciclo de vida da Leishmania, amastigotas vivem no interior de fagolisossomas de células fagocíticas de hospedeiros vertebrados, enquanto promastigotas vivem no interior do vetor invertebrado. Proteases intracelulares como as caspases são as principais efetoras no processo apoptótico. Metacaspases (MCAs) são formas evolutivas distantes das caspases de metazoários, presentes em protozoários, plantas e fungos, e vistas como potenciais alvos para combate dos parasitas sem prejuízo do hospedeiro. Ligantes e moduladores das metacaspases são até hoje desconhecidos. O Phage Display é uma técnica baseada na expressão de proteínas sintéticas nos capsidíos de fagos, usada com o propósito de selecionar ligantes de proteínas, células ou tecidos. Produzimos a metacaspase recombinante de Leishmania L. amazonensis e aplicamos Phage Display para buscar peptídeos ligantes dessa enzima. Esses peptídeos permitiram identificar potenciais proteínas ligantes da MCA, como quinases e cinesinas, que fornecem informações sobre a regulação e controle de sua atividade. Futuramente testaremos se peptídeos ativadores da MCA poderão induzir apoptose do parasita e serem usados como drogas para o tratamento da leishmaniose. / During its life cycle, Leishmania amastigotes live inside phagolysosomes of phagocytic cells of vertebrate hosts, while promastigotes live inside the invertebrate vector. Intracellular proteases such as caspases are key effectors in the apoptotic process. Metacaspases (MCAs) are distant evolutionary forms of metazoan caspases found in protozoa, plants and fungi, and seen as potential targets to destroy the parasites without damage to the host. Ligands and modulators of metacaspases are so far unknown. Phage Display is a technique based on the expression of synthetic proteins in the phage capsid, and is used for selecting ligands of proteins, cells or tissues. We have produced the recombinant metacaspase of Leishmania (L.) amazonensis and employed Phage Display to find peptide ligands of this enzyme. These peptides led to the identification of potential binding proteins of the MCA, such as kinases and kinesin, which provide information about the regulation and control of MCA´s activity. In the future we will test whether peptide activators of MCA nduce apoptosis of the parasite and can be used as drugs for the treatment of leishmaniasis.

MSc (Biochemistry) / Department of Biochemistry / In 2017 malaria cases were estimated at 219 million and of these 435 000 resulted in death. Malaria is transmitted by female Anopheles mosquitoes which thrive in tropical and sub-tropical areas. Malaria is caused by five species from the genus Plasmodium, namely P. falciparum, P. vivax, P. ovale, P. malariae and P. knowlesi. P. falciparum causes the most severe form of the disease. P. falciparum has a complex life cycle in the human and mosquito hosts exposing the parasite to environmental changes, resulting in upregulation of heat shock proteins (Hsps). These Hsps facilitate protein folding and protein disaggregation. Hsp70 is a molecular chaperone whose function is to facilitate protein folding. P. falciparum Hsp70-x is the only member of this family of proteins that is exported to the erythrocyte cytosol by the parasite. PfHsp70-x has been implicated in the development of malaria pathogenesis. This is largely due to its association with P. falciparum erythrocyte membrane protein 1 (PfEMP1), an important virulent factor that is exposed to the exterior of the infected erythrocyte. In tumour cells, cell surface- bound Hsp70 is known to sensitize the tumour cells to cytolytic attack that is mediated by NK cells. Cell surface bound Hsp70 is thought to recruit NK cells and Granzyme B (GrB) via its 14 amino acid sequence, TKDNNLLGRFELSG, known as the TKD motif. Both PfHsp70-x and human Hsp70 (hHsp70) contain the TKD motif. Thus, this study sought to investigate the role of Hsp70 in facilitating the selective targeting of malaria parasite-infected erythrocytes by GrB. To this end, recombinant hHsp70 and PfHsp70-x were successfully expressed in E. coli and purified. Using slot blot and ELISA, it was observed that both PfHsp70-x and hHsp70 directly interact with GrB. PfHsp70-x showed greater affinity for GrB than hHsp70. In addition, using parasites cultured at the erythrocyte stage it was noted that GrB exhibits potent antiplasmodial activity (IC50 of 0.5μM). In addition, the findings suggest that GrB interacts with both Hsp70s (of parasite and human origin) resident in the infected erythrocyte. This makes GrB a promising antimalarial agent. / NRF

(Abstract) Some of heat shock proteins (Hsp), for example the inducible form Hsp70, are expressed on the surface of tumour cells. High Hsp expression is reflected in tumour cell features, such as ability to progression, to metastasize and resistance to apoptosis. The question is whether Hsp gene expression correlates with surface expression. The aim of this master thesis is to compare surface and gene expression of Hsp70 and observe the gene expression of some other Hsp proteins (Hsp27, Hsp60, Hsp90 and HspBP1) in leukaemia. The research was carried out on cell lines obtained from leukaemic blasts of patients with acute myeloid leukaemia: UoC-M1, HL-60, OCI/AML3, THP-1, HU-3 and TF-1 that had been cultivated in vitro. Hsp70 surface expression was detected using flow cytometry, and gene expression of each Hsp was studied using real-time RT-PCR. It was found out that high surface expression of Hsp70 did not correlate with gene expression in consequence of negative feedback applied in Hsp expression regulation. Hsp27 gene expression was increased compared to negative (healthy) control on all tumour cell lines, with the highest increase on the THP-1 line. Hsp60 gene expression was increased compared to negative (healthy) control on all tumour cell lines and there were not remarkable differences in...

A diapause upregulated cDNA clone was isolated from a cDNA library generated from brain mRNA of diapausing Sarcophaga crassipalpis pupae. The clone hybridized to a 1600 bp transcript on a northern blot. The insert is 823 bp in length, has a tentative open reading frame of 615 bp, and codes for a 23 kDa protein. The clone has a high level of identity at the amino acid level with the four small heat shock proteins of Drosophila melanogaster. Northern analysis revealed no detectable expression of the transcript in diapause- or nondiapause-programmed wandering larvae, and only trace expression in nondiapausing pupae. But, the transcript was highly expressed beginning at the onset of diapause and continuing throughout diapause. Expression promptly decreased when diapause was terminated. In nondiapausing individuals the transcript was highly expressed in response to cold shock or heat shock, but temperature stress did not cause greater expression in diapausing pupae. The results imply that expression of this small heat shock protein, a response elicited by temperature stress in nondiapausing individuals, is a normal component of the diapause syndrome. The upregulation of this gene during diapause suggests that it plays an essential role during this overwintering developmental arrest.

Alpha B Crystallin (αBC) is a putative effector protein of ischemic preconditioning (IPC). that is phosphorylated on Ser 45 by ERK1/2 and Set 59 by the p38 MAPK substrate, MAPKAPK-2. Translocation and phosphorylation of αBC was determined in cytosolic and cytoskeletal fractions by 1D SDS-PAGE and IEF, or using Ser 45 and Set 59 phospho-specific antibodies in: (1) control rabbit cardiomyocytes; (2) cells preconditioned by 10 min in vitro ischemia; or after pre-treatment with specific inhibitors of (3) Ser/Thr protein phosphatase 1/2A (calyculin A); (4) p38 MAPK (SB203580); or (5) ERK 1/2 (PD98059); all prior to 180 min ischemia. Ischemia induced a cytosolic to cytoskeletal translocation of αBC, which was similar in all the groups. Highly phosphorylated isoforms (D1/2) of αBC were present in cytosolic but not cytoskeletal fractions at 0 min ischemia. By 60-90 min ischemia. D1/2 isoforms had translocated to the cytoskeletal fraction. Calyculin A maintained D1/2 levels throughout prolonged ischemia. SB203580 decreased αBC phosphorylation. Neither PD98059 nor IPC altered αBC phosphorylation during prolonged ischemia. It is concluded that αBC phosphorylation during ischemia is regulated by p38 MAPK but not by ERK 1/2. The inability to detect a correlation between IPC protection and either αBC translocation or phosphorylation suggests that the proteins in the highly phosphorylated isoform bands of αBC quantitated in this study are not protective end effectors of classical IPC.

Introduction: Myocardial Infarction (MI) is the leading cause of premature death worldwide. During MI-induced ischemia, the release of heat shock proteins (HSPs), a classic damage-associated molecular pattern (DAMP), by severely injured cells leads to prolonged inflammation through their activation of innate pattern recognition receptors, fibrosis, and subsequent contractile dysfunction. The regulation of HSPs is orchestrated by its master transcription factor, Heat Shock Factor 1 (HSF1). However, it is unknown if HSF1 is a potential integrated functional target to improve MI outcomes. We addressed this question by asking if the coordinated modulation of HSPs via genetic deletion of Hsf1 can be beneficial in MI. Hypothesis: We hypothesized that genetic deletion of Hsf1 can lead to improved survival and left ventricle (LV) remodeling through reduction of pro-inflammatory pathway activation in a murine model of MI-induced coronary artery ligation. Methods and Results: Eleven to thirteen-week-old male Hsf1-/- mice and Hsf1+/+ littermate controls were subjected to MI by left anterior descending (LAD) coronary artery ligation or sham operation. Hsf1-/- mice subjected to induced-MI had a significant higher survival rate (74%) at 28 days than WT mice post-MI in the same time frame (34%, p<0.001). Echocardiography at 3, 7, and 28 days post-MI; however, did not identify any difference in LV function between Hsf1+/+ and Hsf1-/- mice. Masson Trichrome and Picro Sirius Red staining of heart tissue sections following 7 days of sham or MI-operation indicated that MI-operated Hsf1-/- hearts had a significant smaller infarct size than Hsf1+/+ hearts at 19% compared to 32% (p<0.05), respectively; and less collagen deposition when compared to WT littermates. Cardiac expression of heat shock proteins was significantly lowered in the Hsf1-/- hearts compared to Hsf1+/+ hearts following 3 and 7 days of MI. However, no significant difference was observed in number of immune cells, cardiac gene expression of pro-inflammatory cytokines and chemokines, cardiac protein expression of NF-κB and MAPK-ERK1/2 signaling proteins, and serum IL-6 concentration between Hsf1+/+ and Hsf1-/- mice 3 days post-MI. Following 7 days of MI, there is a significant increase in the gene expression of pro-inflammatory cytokines, such as Il1b, and chemokines, such as Ccl2, in Hsf1-/- hearts than Hsf1+/+ hearts. Conclusion & Future Directions: Overall, the loss of Hsf1 improved survival and reduced infarct size following MI. However, its deletion did not affect inflammatory processes until 7 days post-MI or improved cardiac function in our specific murine MI model.

No description available.

Several cDNAs isolated from brains of diapausing pupae of the flesh fly, Sarcophaga crassipalpis, show expression patterns unique to diapause. To isolate such cDNAs a diapause pupal brain cDNA library was screened by using an elimination hybridization technique, and cDNAs that did not hybridize with cDNA probes constructed from the RNA of nondiapausing pupae were selected for further screening. The 95 clones that did not hybridize in the initial library screen were selected for further characterization. These clones were then screened against diapause and nondiapause pupal poly(A)+ Northern blots. The secondary screen identified 4 diapause-up-regulated clones, 7 diapause-down-regulated clones, 8 clones expressed equally in both diapause and nondiapause, and 75 clones without detectable expression. The diapause- up-regulated and down-regulated clones were further characterized by partial DNA sequencing and identity searches by using GenBank. Identities between our cloned cDNAs and other genes included those linked to cell cycle progression, stress responses, and DNA repair processes. The results suggest that insect diapause is not merely a shutdown of gene expression but is a unique, developmental pathway characterized by the expression of a novel set of genes.

HspB2 is a small heat shock protein encoded on human chromosome 11. Less than 1000 base pairs away from HSPB2 and situated in a head-to-head orientation lies the gene encoding another small heat shock protein, CRYAB. Because they are uncommonly close to one another they share regulatory elements. In addition, they share protein homology as sHSPs, suggesting that they perhaps perform aimilar functions. SHSPs such as HspB2 and CryAB are traditionally thought to provide protective effects to cells in response to a variety of stress inducers. In response to stress they form complexes around misfolded proteins or proteins in danger of denaturation. HspB2 has been shown to exhibit protective effects during cellular stress and to localize to the Z-line of skeletal muscle. It has also been implicated in cardiac energetics, specifically in the production of ATP, however little is known about its molecular targets. Here I report the use of yeast two-hybrid screening to uncover the molecular targets of HspB2. I also detail the process by which the screens are performed as well as the verification steps, including co-precipitation experiments in mammalian cells. Through these studies we identify many novelbinding partners of HspB2, including CryAB as well as multiple muscle and mitochondrial proteins. Proteins discovered to bind to HspB2 include such proteins as actin and myosin, enzymes catalyzing various steps of glycolysis and the electron transport chain, as well as redox-, small heat shock protein-, kinase-, and electrolyte-related proteins, among others. Studies of the binding partners of HspB2 in cardiac tissue will provide important information clarifying the involvement of HspB2 in cardiac muscle maintenance and metabolism.