RECK stands for ¡¥reversion-inducing cysteine-rich protein with Kazal motifs¡¦. This gene was initially discovered by screening a human fibroblast cDNA library for genes giving rise to reversion-inducing clones when transfected into v-Ki-ras transformed NIH3T3 cells. The key action of RECK is to inhibit matrix metalloproteinases (MMPs), and it has a significant effect on limiting tumor invasion. Located within the middle part of RECK protein are three serine protease inhibitor-like (SPI) domains (635-654,716-735 and 754-772 amino acids, respectively) which are similar to Kazal motif. Kazal motif is a peptidase inhibitor motif containing disulfide bonds with small alpha and beta folds. The first of these SPI is identical to the Kazal motif (named as K1) and the other two SPIs are highly similar to the Kazal motif (named as K2 & K3). Given RECK is a MMP inhibitor, these SPI-like domains are likely to have a significant role in MMP inhibition. Our previous data indicated that K23 motifs of RECK protein can inhibit MMP-9 secretion and activity and attenuate metastasis of lung cancer cells. To go a step further, we constructed secretory mammalian expression vectors which could produce K1, K2 and K3 to investigate their effect on MMP activity and cell invasion. We found that K2 also exhibited inhibitory activity on MMP activity and cell invasion. Thus, these finding indicate that the K2 domain of RECK function may be developed as a peptide inhibitor of tumor invasion.

A osteoporose é uma doença osteometabólica que atinge milhares de pessoas; e as doenças cardiovasculares são as principais causas de mortes no mundo. Estudos demonstram que pacientes com baixa densidade mineral óssea apresentam maior risco de desenvolverem doenças cardiovasculares. No entanto, os mecanismos patológicos, fisiológicos e moleculares que correlacionam a osteoporose e a aterosclerose ainda são desconhecidos. O objetivo deste estudo in vivo foi realizar avaliação histológica e imuno-histoquímica do osso fêmur de camundongos ovariectomizados e ateroscleróticos após tratamento com três drogas: doxiciclina, atorvastatina e vitamina D. Foram utilizados 36 camundongos fêmeas, como controle (linhagem C57BL/6), divididos aleatoriamente em seis grupos: Grupo I: Água; Grupo II: Etanol; Grupo III: Azeite; Grupo IV: Doxiciclina; Grupo V: Atorvastatina e Grupo VI: Vitamina D; e 36 camundongos fêmeas knockout para Apolipoproteína E (ApoE-/-) divididos aleatoriamente em seis grupos: Grupo VII: Água OVX; Grupo VIII: Etanol OVX; Grupo IX: Azeite OVX; Grupo X: Doxiciclina OVX; Grupo XI: Atorvastatina OVX e Grupo XII: Vitamina D OVX. Após indução dos quadros de osteoporose e aterosclerose foi realizado o tratamento conforme cada grupo. Decorrido o tempo experimental, os animais foram eutanasiados e o material coletado submetido ao processamento histotécnico para análise histológica, em cortes corados com Tricrômio de Masson e avaliação da expressão por imunohistoquímica de TRAP, IL-1β, TNF-α, RANKL e MMP-9. Os resultados obtidos foram submetidos à análise estatística por meio dos testes One-Way ANOVA, seguido pelo pósteste de Bonferroni (histologia e colesterol); Kruskal Wallis e Student-Newman-Keuls (imuno-histoquímica). O nível de significância adotado foi de 5%. Os resultados obtidos evidenciaram diferença significativa entre o número de células imunorreativas para MMP-9, TRAP, IL-1β, TNF-α e RANKL nos grupos VII e X; VIII e XI; demonstrando a ação da Doxiciclina e Atorvastatina sob tais moléculas. Os resultados histológicos evidenciaram a eficácia da vitamina D no tratamento da osteoporose, uma vez que promoveu aumento da área óssea / Osteoporosis is an osteometabolic disease that affects thousands of people; and cardiovascular diseases are the leading causes of death in the world. Studies have shown that patients with low bone density are at a higher risk of developing cardiovascular disease. However, the pathological, physiological and molecular mechanisms that are correlated to osteoporosis and atherosclerosis are still unknown. The present work in vivo was to perform a histological and immunohistochemical evaluation of the femoral bone of ovariectomized and atherosclerotic mice after treatment with three drugs: doxycycline, atorvastatin and vitamin D. Thirty-six female mice were used as controls (C57BL/6 strain) randomly divided into six groups: Group I: Water; Group II: Ethanol; Group III: Olive oil; Group IV: Doxycycline; Group V: Atorvastatin and Group VI: Vitamin D; and the 36 knockout mice for Apolipoprotein E (ApoE-/-) randomly divided into six groups: Group VII: Water OVX; Group VIII: Ethanol OVX; Group IX: OVX olive oil; Group X: Doxycycline OVX; Group XI: Atorvastatin OVX and Group XII: Vitamin D OVX. After induction of osteoporosis and atherosclerosis, treatment was performed according to each group. After the experimental time, the animals were euthanized and the collected material submitted to histotechnical processing for histological analysis in stained sections with Masson\'s Trichrome and evaluation of the expression by immunohistochemistry of TRAP, IL-1β, TNF-α, RANKL and MMP-9. The results were submitted to statistical analysis using One-Way ANOVA, followed by Bonferroni post-test (histology and cholesterol); Kruskal Wallis and Student-Newman-Keuls (immunohistochemistry). The level of significance was 5%. The results obtained showed a significant difference between the number of immunoreactive cells for MMP-9, TRAP, IL-1β, TNF-α and RANKL in groups VII and X; VIII and XI; demonstrating the action of Doxycycline and Atorvastatin on such molecules. The histological results evidenced the efficacy of vitamin D in the treatment of osteoporosis, since it promoted increased bone area

Coronaviruses (CoVs) comprise a family of enveloped viruses that cause respiratory disease in humans, including CoV disease 2019 (COVID-19), caused by severe-acute respiratory syndrome CoV-2 (SARS-CoV-2). For CoV infection to occur, the CoV spike (S) protein must mediate fusion between the viral and host membranes. This entry process can also be repurposed during infection to promote cell-to-cell fusion, further contributing to viral spread. To trigger fusion, S must bind its cognate receptor and be cleaved by host proteases. Identifying cellular proteases capable of triggering CoV fusion is critical to understand CoV entry, tropism, and cell-cell spread, however the range of proteases capable of promoting CoV fusion has not been fully explored. Here, using fusion and entry assays, I provide evidence implicating matrix metalloproteinase-9 (MMP-9) as a fusion trigger for SARS-CoV-2 and HCoV-229E. Additionally, I show MMP-9 expression is upregulated during CoV infection, highlighting its potential relevance as a CoV triggering factor.

Molecular-targeting therapeutics directed towards growth factor receptors have become promising interventions in cancer. They include the family of mammalian receptor tyrosine kinases such as epidermal growth factor, TrkA and insulin. In particular, the insulin receptor (IR) is one of the most well-known members of the RTK family of receptors playing a role in cancer. IRs are covalently-linked heterodimers of αβ subunits on the cell membrane in the absence of insulin. The IR signaling pathways are initially triggered by insulin binding to the α subunits followed by the interaction of β subunits and ATP. The parameter(s) controlling IR activation remains unknown. Here, we report a membrane receptor signaling platform initiated by insulin binding to its receptor to induce Neu1 in live HTC-IR and MiaPaCa-2 cell lines. Microscopy colocalization and co-immunoprecipitation analyses reveal that Neu1 and MMP9 form a complex with naïve and insulin-treated receptors. Tamiflu (neuraminidase inhibitor), galardin and piperazine (broad range MMP inhibitors), MMP9 specific inhibitor and anti-Neu1 antibody blocked Neu1 activity associated with insulin stimulated live cells. Moreover, Tamiflu, anti-Neu1 antibody, and MMP9 specific inhibitor blocked insulin induced insulin receptor substrate-1 phosphorylation (p-IRS1). The previous findings reveal a molecular organizational signaling platform of Neu1 and MMP-9 crosstalk in alliance with insulin receptors. It proposes that insulin binding to the receptor induces MMP9 to activate Neu1, which hydrolyzes α-2,3 sialic acid in removing steric hindrance to generate a functional receptor. The results predict a prerequisite desialylation process by activated Neu1. A complete understanding of IR activation and the role of sialic acids in the iii signaling pathways may provide a therapeutic strategy in the prevention of different diseases such as diabetes mellitus and cancer. / Thesis (Master, Microbiology & Immunology) -- Queen's University, 2013-02-20 11:27:44.861

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Arsenic (As) exposure is associated with cancer, lung and cardiovascular disease, yet the mechanisms involved are not clearly understood. Elevated matrix metalloproteinase-9 (MMP-9) levels are also associated with these diseases, as well as with exposure to water As. Our objective was to evaluate the effects of dietary components of inorganic As (iAs) intake on serum MMP-9 concentration at differing levels of tap water As. In a cross-sectional study of 214 adults, dietary iAs intake was estimated from 24-h dietary recall interviews using published iAs residue data; drinking and cooking water As intake from water samples and consumption data. Aggregate iAs intake (food plus water) was associated with elevated serum MMP-9 in mixed model regression, with and without adjustment for covariates. In models stratified by tap water As, aggregate intake was a significant positive predictor of serum MMP-9 in subjects exposed to water As≤10 μg/l. Inorganic As from food alone was associated with serum MMP-9 in subjects exposed to tap water As≤3 μg/l. Exposure to iAs from food and water combined, in areas where tap water As concentration is ≤10 μg/l, may contribute to As-induced changes in a biomarker associated with toxicity.

Inflammatory processes mark all stages of atherogenesis. One of the key regulators of inflammation is the transcription factor nuclear factor kappa B (Nf-kb). Nf-kb is the general name for a whole family of dimeric transcription factors. One can distinguish between a classical and an alternative pathway with Rela/p50 (Nf-kb1) and Relb/p52 (Nf-kb2) representing the terminal transcription factors, respectively. Classical Nf-kb1 signaling has been associated with atherosclerotic lesion development many times, mainly because of its regulation of many pro-inflammatory proteins with an established role in atherogenesis. Recent studies provided evidence of crosstalk between classical Nf-kb1 and alternative Nf-kb2 signaling, implicating a potential role for Nf-kb2 in atherogenesis. The aim of the present study was to investigate the influence of Nf-kb2 on atherosclerotic lesion development in a knockout mouse model. Nfkb2 knockout (Nfkb2-/-) mice were generated on two different atherosclerosis sensible backgrounds, the Apoe- and Ldlr- deficient background. Quantification of atherosclerotic lesion development showed, that Nfkb2-/- mice developed significantly more atherosclerosis at the brachiocephalic artery than wild type controls, indicating a protective effect of Nf-kb2 on atherogenesis. Further expression analyses in bone marrow-derived macrophages (BMDM) revealed highly significant upregulation of matrix metalloproteinase 9 (Mmp9) in Nfkb2-/- mice. Overexpression of Mmp9 was associated with enhanced macrophage migration across extracellular matrix in vitro and an inflammatory plaque phenotype with advanced, macrophage-rich lesions. Accordingly, increased Mmp9 expression in Nfkb2-/- macrophages might have contributed to enhanced lesion development in these mice.

O receptor NLRP12 é um receptor intracelular que está envolvido no reconhecimento de PAMPs e DAMPs durante uma infecção. Foi visto que durante a osteoclastogênese, há uma diminuição da transcrição de NLRP12, e que este receptor inibe a reabsorção óssea através da supressão da via alternativa de NF-κB, exercendo um papel protetor sobre o tecido ósseo. Além disso, foi observado que a deficiência de NLRP12 em monócitos sob o estímulo de RANKL levou a maior estabilização de NIK e maior translocação de RelB para o núcleo, aumentando a formação dos osteoclastos in vitro. Portanto, o objetivo deste estudo foi avaliar o papel de NLRP12 no desenvolvimento e progressão da lesão periapical induzida em camundongos. Para isso, foi induzida a lesão periapical dos primeiros molares inferiores dos camundongos fêmeas C57/Bl6 (WT) e camundongos deficientes para o receptor NLRP12 (Nlrp12-/-). Após 14 e 21 dias, as amostras de mandíbula foram submetidas às análises: determinação da área de lesão periapical em cortes histológicos; expressão gênica de marcadores osteoclastogênicos por qPCR; contagem de osteoclastos submetidos ao ensaio de histoenzimologia (TRAP); avaliação enzimática das MMPs por Zimografia. Os linfonodos cervicais foram submetidos à análise da expressão dos fatores de transcrição T-bet, RORγt, GATA-3 e Foxp-3 por qPCR. Aos 14 dias, na análise histomorfométrica os animais Nlrp12-/- apresentaram uma maior lesão periapical quando comparados aos animais WT, associado com o aumento da expressão de Trap, Catepsina K e MMP-9 em amostras de hemi-mandíbulas com lesão. Além disso, o número de células TRAP positivas foi significantemente maior em Nlrp12-/- com lesão quando comparado com seu controle, enquanto no grupo WT com e sem lesão foram semelhantes. Assim como foi observado o maior aumento dos osteoclastos presentes no local da lesão dos animais Nlrp12-/-, estes também se mostraram com maior atividade gelatinolítica de MMP-9 e MMP-2 em relação ao seu controle, diferente dos animais WT que não apresentaram diferença entre os grupos controle e com lesão. Ainda nesse período, foi observado nas amostras de linfonodos cervicais que, no grupo Nlrp12-/- houve uma tendência à maior expressão de RORγt, seguidos de menor expressão de T-bet quando comparados com o grupo WT. Aos 21 dias, os animais WT e Nlrp12-/- apresentaram lesões periapicais de tamanhos semelhantes. Além disso, somente o grupo Nlrp12-/- com lesão apresentou um aumento significativo da expressão de Trap em relação ao seu controle e a expressão de Catepsina K foi semelhante em ambos os grupos. Neste período houve um aumento na quantidade de células TRAP positivas em ambos os grupos com lesão quando comparados com seus respectivos controles, entretanto também não houve diferença entre os animais WT e Nlrp12-/-. A atividade de MMP-9 e MMP-2 foram semelhantes entre os animais WT e Nlrp12-/- e entre seus respectivos controles aos 21 dias. Nossos dados sugerem que a deficiência de NLRP12 levou a uma maior perda óssea aos 14 dias de lesão periapical e que isso ocorre via modulação da formação e atividade dos osteoclastos. Portanto, o NLRP12 inibe a osteoclastogênese e a atividade dos osteoclastos durante a fase inicial da lesão periapical, retardando o desenvolvimento da doença. / NLRP12 is an intracellular sensor that recongnizes PAMPS and DAMPs during infeccion. It was seen that NLRP12 transcription is down-regulated during osteoclastogenesis, and NLRP12 protect bone via suppression of alternative NF-κB-induced osteoclastogenesis. It has been shown that NLRP12 deficiency in monocytes under RANKL stimuli exhibited more stabilization of NIK and nuclear translocation of RelB, increasing osteoclasts formation in vitro. Therefore, the aim of this study was to evaluate the role of NLRP12 in the development and progression of experimentally induced periapical lesions in mice. Periapical lesions were induced in first molars of WT and NLRP12 knockout (KO) mice. Samples were collected at 14 and 21 days of the lesion for the analyses. Jaw samples with lesion and control area were subjected to periapical lesions area determination by histological sections; osteoclastogenic markers expression by q-PCR; count of osteoclasts submitted to the enzyme assay for TRAP; evaluation of MMPs activity by Zymography. The expression of T cells markers´ transcription factors was evaluated in lymph nodes by q-PCR. Fourteen days after periapical lesion induction, histological analysis revealed that NLRP12KO mice exhibited higher area of periapical lesion compared to WT group, which was associated with up-regulated mRNA expression of Trap, Cathepsin K and MMP-9 in the jaw samples. Moreover, the number of multinuclear TRAP-stained cells was significantly higher in the NLRP12KO with lesion group when compared to it control, whereas in the WT the number between the lesion and control groups were similar. Still, NLRP12KO showed higher MMP-9 and -2 gelatinolytic activity than it control, unlike WT mice that showed no difference between control and lesion group. In this period, NLRP12KO mice lymph nodes showed more RORγt expression than WT mice and less T-bet expression. At 21 days, WT and NLRP12KO presented periapical lesions of similar sizes. In addition, NLRP12KO group with lesion showed a significant increase in Trap expression when compared with their control, but the increase in Trap e Cathepsin K was similar in both groups. Additionally, there was an increase of multinuclear TRAP-stained cells in both lesion groups when compared with their respective controls; however, there was also no difference between WT and NLRP12KO mice. MMP-9 and -2 activity was similar between WT and NLRP12KO and with their respective controls at 21 days. Our results suggest that NLRP12 deficiency led to increased bone loss at 14 days of periapical lesion and it occurs due to increased osteoclasts formation and activity. Therefore, NLRP12 inhibits osteoclastogenesis and osteoclasts activity during the early stages of periapical lesion, slowing the development of the disease.