Bobel-24 Activity against Cryptosporidium parvum in Cell Culture and in a SCID Mouse Model

Abstract

The anticryptosporidial activity of Bobel-24 (2,4,6-triiodophenol) was studied for the first time, resulting in a reduction of the in vitro growth of Cryptosporidium of up to 99.6%. In a SCID mouse model of chronic cryptosporidiosis, significant differences (P < 0.05) in oocyst shedding were observed in animals treated with 125 mg/kg/day. These results merit further investigation of Bobel-24 as a chemotherapeutic option for cryptosporidiosis.Cryptosporidium parvum is considered one of the top four causes of self-limiting diarrhea in humans and in several animal species (15). In immunocompromised individuals, cryptosporidial infection may become chronic and life threatening because no completely effective treatment is available (7).The molecular mechanism involved in the initial interaction between C. parvum sporozoites and epithelial cells is still unclear. One of the mechanisms of C. parvum attachment is the interaction between galactose-N-acetylgalactosamine (Gal/ GalNAc) epitopes on the epithelial apical membrane and Gal/ GalNAc-specific sporozoite surface lectins (3). Invasion by and intracellular development of the parasite lead to the destruction of epithelial cells, resulting in blunting of intestinal villi, crypt hyperplasia, and cytoskeletal remodeling. In addition, there are decreased sodium absorption, epithelial chemokine production, and increased prostaglandin production (16), which are directly related to the notable inflammatory response that follows Cryptosporidium infection and characterizes its pathology (9).To further the improvement of treatment against cryptosporidiosis, we studied the anticryptosporidial activity of 4,. This compound is able to inhibit lectin expression (11). In addition, Bobel-24 is considered a dual inhibitor of lipoxygenase and cyclooxygenase, which are involved in the resolution of inflammatory diseases (10, 13).The C. parvum IOWA bovine isolate used for this study was kindly provided by M. J. Arrowood (Centers for Disease Control and Prevention, Atlanta, GA). Bobel-24 is a nonsteroidal antiinflammatory compound (Fig. 1) (6, 10, 11). It is under clinical development as a potent leukotriene B 4 synthesis inhibitor (17). For in vitro studies, Bobel-24, used as a pure compound (purity of 99.6%, obtained from Chemical Iberica SL, Salamanca, Spain), was first dissolved in dimethyl sulfoxide (DMSO) and then diluted with phosphate-buffered saline. In an MTT cytotoxicity assay (5), viability percentages (Ͼ95%) of HCT-8 cells with Bobel-24 concentrations lower than 100 M were observed. To study in vitro activity of Bobel-24, 8 ϫ 10 5 excysted oocysts/ml (1) were inoculated in confluent HCT-8 cell monolayers as previously described (2). To assess the effect on sporozoite attachment to HCT-8 cells, we incubated sporozoite suspensions with Bobel-24 (90 M) before use, we incubated HCT-8 cells with Bobel-24 (90 M) before infection, and to evaluate the effect of Bobel-24 on C. parvum development in HCT-8, we incubated infected cells afterwards with 90 M Bobel-24 for 48 h. Paromomycin ...

Activity of an anti-inflammatory drug against cryptosporidiosis in neonatal lambs

“…However, oocyst shedding, patent period and diarrhoea were notably reduced after administration of a prophylactic/therapeutic treatment (Bobel-24 at 50 mg/ kg). Similar results were obtained by Rueda et al (2008) with an in vivo model of chronic cryptosporidiosis (SCID mouse). C. parvum infection increases the concentrations of tissue prostaglandins (by up to 50% of baseline levels) in both pigs and humans (Argenzio et al, 1990;Laurent et al, 1998) and diarrhoea has been partially attributed to the local production of prostanoid (Argenzio et al, 1993(Argenzio et al, , 1996.…”

“…Preincubation of cell monolayers with either lectins specific to Gal/GalNAc, or glycosidases that specifically release Gal/GalNAc oligosaccharides from glycoproteins, decreased attachment by up to 80% (Chen and LaRusso, 2000). This may be why Bobel-24 was able to inhibit up to 99.6% of the infection of HCT-8 cells by Cryptosporidium sporozoites (Rueda et al, 2008). In the present study, Bobel-24 was not able to completely prevent infection by C. parvum in neonatal lambs.…”

“…It has been found that Bobel-24 is a dual inhibitor of lipooxygenase and cyclooxygenase, which may be important in the treatment of anti-inflammatory diseases Norton, 1997, 1999;García-Capdevila et al, 1998;Parreño et al, 2006). Moreover, it has been shown that Bobel-24 is an inhibitor of L-selectine expression; this molecule is crucial for the attachment of Cryptosporidium sporozoites to epithelial cells (Chen and LaRusso, 2000;Rueda et al, 2008). The aim of the present study was to evaluate the antiparasitic activity of Bobel-24 against C. parvum infection in neonatal lambs.…”

Kinetic properties and small‐molecule inhibition of human myosin‐6

“…TIP, also known as Bobel‐24 or AM‐24, has been described as a nonsteroid anti‐inflammatory molecule due to its inhibitory effect on leukotriene B4 (LTB4) synthesis [16]. Additionally, TIP acts as a thyroid hormone disrupting chemical and displays potent anti‐cryptosporidial activity [17,18]. Our results show that TIP, when used in low micromolar concentrations, is targeted to myosin‐6.…”

Validation of IMP Dehydrogenase Inhibitors in a Mouse Model of Cryptosporidiosis

“…Paromomycin is effective in rodents and has also been used to treat cryptosporidiosis, though a significant benefit has not been demonstrated in humans (13). Approximately 20 additional compounds have displayed at least some anticryptosporidial activity in animal models (14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26). Unfortunately, as with nitazoxanide, the targets of most of these compounds have not been identified, which makes further development difficult.…”