PATRICK JACK SPENCER

PATRICK JACK SPENCER

(Fonte: Lattes)

Resumo

Possui graduação em Ciências Biológicas pela Universidade Presbiteriana Mackenzie (1991), mestrado em Tecnologia Nuclear pela Universidade de São Paulo (1995) e doutorado em Tecnologia Nuclear pela Universidade de São Paulo (2000) tendo sido bolsista sandwich no US Army Medical Research Institute for Infeccious Diseases (98-99). É responsável pelo Biotério de criação e manutenção de animais de laboratório do IPEN. Tem experiência na área de Bioquímica, com ênfase em Proteínas, atuando principalmente nos seguintes temas: veneno, proteínas, bothrops, irradiação e miotoxina.(Texto extraído do Currículo Lattes em 22 dez. 2021)

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Anti-Metalloproteases
2023 - GODOI, KEMILY S. de; GUIDOLIN, FELIPE R.; PORTARO, FERNANDA C.V.; SPENCER, PATRICK J.; SILVA, WILMAR D. da
Bitis arietans is a medically important snake found in Sub-Saharan Africa. The envenomation is characterized by local and systemic effects, and the lack of antivenoms aggravates the treatment. This study aimed to identify venom toxins and develop antitoxins. The F2 fraction obtained from Bitis arietans venom (BaV) demonstrated the presence of several proteins in its composition, including metalloproteases. Titration assays carried out together with the immunization of mice demonstrated the development of anti-F2 fraction antibodies by the animals. The determination of the affinity of antibodies against different Bitis venoms was evaluated, revealing that only BaV had peptides recognized by anti-F2 fraction antibodies. In vivo analyses demonstrated the hemorrhagic capacity of the venom and the effectiveness of the antibodies in inhibiting up to 80% of the hemorrhage and 0% of the lethality caused by BaV. Together, the data indicate: (1) the prevalence of proteins that influence hemostasis and envenomation; (2) the effectiveness of antibodies in inhibiting specific activities of BaV; and (3) isolation and characterization of toxins can become crucial steps in the development of new alternative treatments. Thus, the results obtained help in understand
Antibodies as snakebite antivenoms
2022 - SILVA, WILMAR D. da; ANDRADE, SONIA A. de; MEGALE, ANGELA A.A.; SOUZA, DANIEL A. de; SANTANNA, OSVALDO A.; MAGNOLI, FABIO C.; GUIDOLIN, FELIPE R.; GODOI, KEMILY S.; SALADINI, LUCAS Y.; SPENCER, PATRICK J.; PORTARO, FERNANDA C.V.
Snakebite envenomation is considered a neglected tropical disease, affecting tens of thousands of people each year. The recommended treatment is the use of antivenom, which is composed of immunoglobulins or immunoglobulin fragments obtained from the plasma of animals hyperimmunized with one (monospecific) or several (polyspecific) venoms. In this review, the efforts made in the improvement of the already available antivenoms and the development of new antivenoms, focusing on snakes of medical importance from sub-Saharan Africa and Latin America, are described. Some antivenoms currently used are composed of whole IgGs, whereas others use F(ab’)2 fragments. The classic methods of attaining snake antivenoms are presented, in addition to new strategies to improve their effectiveness. Punctual changes in immunization protocols, in addition to the use of cross-reactivity between venoms from different snakes for the manufacture of more potent and widely used antivenoms, are presented. It is known that venoms are a complex mixture of components; however, advances in the field of antivenoms have shown that there are key toxins that, if effectively blocked, are capable of reversing the condition of in vivo envenomation. These studies provide an opportunity for the use of monoclonal antibodies in the development of new-generation antivenoms. Thus, monoclonal antibodies and their fragments are described as a possible alternative for the production of antivenoms, regardless of the venom. This review also highlights the challenges associated with their development.
Bradykinin-potentiating and related peptides from reptile venoms
2021 - PIMENTA, DANIEL C.; SPENCER, PATRICK J.
Evolution has provided venomous snakes with a vast arsenal of molecules able to interfere in several physiological processes. The ultimate role of these toxins, which are proteins or peptides, is to subdue the prey, although digestive functions should also be considered. Among these toxins, some are vasoactive peptides, which induce a drastic drop in blood pressure. This effect is attributed mostly to bradykinin-potentiating peptides, although other venom peptides have been shown to interfere with blood pressure. Bradykinin-potentiating peptides are modular in nature, with highly conserved motifs, and present high proline content, a pyroglutamate at the N-terminal and an IPP motif at the C-terminal. These peptides are potent and highly selective inhibitors of angiotensin-converting enzyme, a crucial molecule for blood pressure regulation, and display K i s as low as 8 nM. Besides the enzyme inhibition, some of these peptides might cross the cell membrane, interfering in the production of nitric oxide, another modulator of blood vessel tonus. Evolution frequently results in physiological redundancies. Such a fact is reflected by the occurrence of another class of blood pressure–modulating toxins. C-type natriuretic peptides can be considered as such. Apparently, these toxins increase guanylate cyclase levels, inducing vasorelaxation. These peptides are being considered as drug leads for congestive heart failure. While C-type natriuretic peptides are still under investigation as potential drugs, bradykinin-potentiating peptide–derived drugs are the boldest example of the use of a deleterious “toxin” as a building block for a cheap drug that benefits a huge number of human beings.
Characterization and evaluation of the enzymatic activity of tetanus toxin submitted to cobalt-60 gamma radiation
2021 - SARTORI, GISELLE P.; COSTA, ANDREA da; MACARINI, FERNANDO L. dos S.; MARIANO, DOUGLAS O.C.; PIMENTA, DANIEL C.; SPENCER, PATRICK J.; NALI, LUIZ H. da S.; GALISTEO JUNIOR, ANDRES J.
Background Tetanus toxin blocks the release of the inhibitory neurotransmitters in the central nervous system and causes tetanus and its main form of prevention is through vaccination. The vaccine is produced by inactivation of tetanus toxin with formaldehyde, which may cause side effects. An alternative way is the use of ionizing radiation for inactivation of the toxin and also to improve the potential immunogenic response and to reduce the post-vaccination side effects. Therefore, the aim of this study was to characterize the tetanus toxin structure after different doses of ionizing radiation of 60Co. Methods Irradiated and native tetanus toxin was characterized by SDS PAGE in reducing and non-reducing conditions and MALD-TOF. Enzymatic activity was measured by FRET substrate. Also, antigenic properties were assessed by ELISA and Western Blot data. Results Characterization analysis revealed gradual modification on the tetanus toxin structure according to doses increase. Also, fragmentation and possible aggregations of the protein fragments were observed in higher doses. In the analysis of peptide preservation by enzymatic digestion and mass spectrometry, there was a slight modification in the identification up to the dose of 4 kGy. At subsequent doses, peptide identification was minimal. The analysis of the enzymatic activity by fluorescence showed 35 % attenuation in the activity even at higher doses. In the antigenic evaluation, anti-tetanus toxin antibodies were detected against the irradiated toxins at the different doses, with a gradual decrease as the dose increased, but remaining at satisfactory levels. Conclusion Ionizing radiation promoted structural changes in the tetanus toxin such as fragmentation and/or aggregation and attenuation of enzymatic activity as the dose increased, but antigenic recognition of the toxin remained at good levels indicating its possible use as an immunogen. However, studies of enzymatic activity of tetanus toxin irradiated with doses above 8 kGy should be further analyzed.
Molecular model of cytotoxin-1 from Naja mossambica mossambica venom in complex with chymotrypsin
2015 - MUNAWAR, AISHA; AKREM, AHMED; HUSSAIN, ASHIQ; SPENCER, PATRICK; BETZEL, CHRISTIAN
Snake venom is a myriad of biologically active proteins and peptides. Three finger toxins are highly conserved in their molecular structure, but interestingly possess diverse biological functions. During the course of evolution the introduction of subtle mutations in loop regions and slight variations in the three dimensional structure, has resulted in their functional versatility. Cytotoxin-1 (UniProt ID: P01467), isolated from Naja mossambica mossambica, showed the potential to inhibit chymotrypsin and the chymotryptic activity of the 20S proteasome. In the present work we describe a molecular model of cytotoxin- 1 in complex with chymotrypsin, prepared by the online server ClusPro. Analysis of the molecular model shows that Cytotoxin-1 (P01467) binds to chymotrypsin through its loop I located near the N-terminus. The concave side of loop I of the toxin fits well in the substrate binding pocket of the protease. We propose Phe10 as the dedicated P1 site of the ligand. Being a potent inhibitor of the 20S proteasome, cytotoxin-1 (P01467) can serve as a potential antitumor agent. Already snake venom cytotoxins have been investigated for their ability as an anticancer agent. The molecular model of cytotoxin-1 in complex with chymotrypsin provides important information towards understanding the complex formation.
Characterization and evaluation of the enzymatic activity of tetanus toxin submitted to gamma radiation by Cobalt 60
2019 - SARTORI, GISELLE P.; COSTA, ANDREA; MACARINI, FERNANDA L.S.; MARIANO, DOUGLAS O.C.; PIMENTA, DANIEL C.; SPENCER, PATRICK J.; GALISTEO JUNIOR, ANDRES J.
Tetanus is a neurological disease which blocks the inhibitory neurotransmitters liberation. Also treatment does not cure the disease, and its main form of prevention is through vaccination. The vaccine is produced by the inactivation of tetanic toxin (TeNT) with formaldehyde, which may cause side effects. An alternative way is the use of ionizing radiation for inactivation of the toxin and also to improve the potential immunogenic response and to reduce the pos-vaccination side effects. Therefore, the aim of this study was to characterize the TeNT structure after different doses of ionizing radiation of Cobalt 60, and also to assess the enzymatic activity after the radiation. SDS PAGE and MALDI-TOF analysis revealed gradual modification on the TeNT structure according to doses increase. Also, fragmentation and possible aggregations of the protein fragments were observed in higher doses. In the analysis of peptide preservation by enzymatic digestion and mass spectrometry, there was a slight modification in the recognition up to the dose of 4 kGy at subsequent doses, recognition was minimal. The analysis of the enzymatic activity by fluorescence showed a 35 % attenuation in the activity even at higher doses. In the antigenic evaluation performed by ELISA and Western Blot, anti-TeNT antibodies were detected against the irradiated toxins at the different doses, with a gradual decrease as the dose increased, but remaining at satisfactory levels, indicating the possibility of possible use as an immunogen, however, studies of enzymatic activity on higher should be further analyzed.
Estudo dos efeitos da radiação gama de sup(Co na bothropstoxina 1 do veneno de Bothrops jararacussu
2007 - SILVA, DIEGO de A.; SILVA, MURILO C. da; SPENCER, PATRICK J.
Clonagem, sequenciamento e expressão de um bloqueador de cálcio da aranha Phoneutria nigriventer
2006 - CALVO, FERNANDA B.; SPENCER, PATRICK J.
Isolamento das toxinas do veneno de Crotalus durissus terrificus
2015 - FERNANDES, MARINA G.; SPENCER, PATRICK J.
Venomics of the Australian eastern brown snake (Pseudonaja textilis): Detection of new venom proteins and splicing variants
2015 - VIALA, VINCENT L.; HILDEBRAND, DIANA; TRUSCH, MARIA; FUCASE, TAMARA M.; SCIANI, JULIANA M.; PIMENTA, DANIEL C.; ARNI, RAGHUVIR K.; SCHLUTER, HARTMUT; BETZEL, CHRISTIAN; MIRTSCHIM, PETER; DUNSTAN, NATHAN; SPENCER, PATRICK J.