Ben-JNK signaling is required for host mortality during Periplaneta fuliginosa densovirus infection.

BACKGROUND: Cockroaches are widely acknowledged as significant vectors of pathogenic microorganisms. The Periplaneta fuliginosa densovirus (PfDNV) infects the smoky-brown cockroach P. fuliginosa and causes host mortality, which identifies the PfDNV as a species-specific and environmentally friendly biopesticide. However, although the biochemical characterization of PfDNV has been extensively studied, the immune response against PfDNV remains largely unclear. RESULTS: Here, we investigated the replication of PfDNV and its associated pathological phenotype in the foregut and hindgut. Consequently, we dissected and performed transcriptome sequencing on the foregut, midgut, and hindgut separately. We revealed the up-regulation of immune response signaling pathway c-Jun N-terminal kinase (JNK) and apoptosis in response to viral infection. Furthermore, knockdown of the JNK upstream gene Ben resulted in a decrease in virus titer and delayed host mortality. CONCLUSION: Taken together, our findings provide evidence that the Ben-JNK signaling plays a crucial role in PfDNV infection, leading to excessive apoptosis in intestinal tissues and ultimately resulting in the death of the host. Our results indicated that the host response to PfDNV fosters viral infection, thereby increasing host lethality. This underscores the potential of PfDNV as a viable, environmentally friendly biopesticide. © 2024 Society of Chemical Industry.

E93 is indispensable for reproduction in ametabolous and hemimetabolous insects.

Ecdysone-induced protein 93 (E93), known as the 'adult-specifier' transcription factor in insects, triggers metamorphosis in both hemimetabolous and holometabolous insects. Although E93 is conserved in ametabolous insects, its spatiotemporal expression and physiological function remain poorly understood. In this study, we first discover that, in the ametabolous firebrat Thermobia domestica, the previtellogenic ovary exhibits cyclically high E93 expression, and E93 mRNA is broadly distributed in previtellogenic ovarioles. E93 homozygous mutant females of T. domestica exhibit severe fecundity deficiency due to impaired previtellogenic development of the ovarian follicles, likely because E93 induces the expression of genes involved in ECM (extracellular matrix)-receptor interactions during previtellogenesis. Moreover, we reveal that in the hemimetabolous cockroach Blattella germanica, E93 similarly promotes previtellogenic ovarian development. In addition, E93 is also essential for vitellogenesis that is necessary to guarantee ovarian maturation and promotes the vitellogenesis-previtellogenesis switch in the fat body of adult female cockroaches. Our findings deepen the understanding of the roles of E93 in controlling reproduction in insects, and of E93 expression and functional evolution, which are proposed to have made crucial contributions to the origin of insect metamorphosis.

The steroid-induced microRNA let-7 regulates developmental growth by targeting cdc7 in the Drosophila fat body.

In insects, 20-hydroxyecdysone (20E) limits systemic growth by triggering developmental transitions. Previous studies have shown that 20E-induced let-7 exhibits crosstalk with the cell cycle. Here, we examined the underlying molecular mechanisms and physiological functions of 20E-induced let-7 in the fat body, an organ for energy storage and nutrient mobilization which plays a critical role in the larval growth. First, the overexpression of let-7 decreased the body size and led to the reduction of both nucleolus and cell sizes in the larval fat body. In contrast, the overexpression of let-7-Sponge increased the nucleolus and cell sizes. Moreover, we found that cdc7, encoding a conserved protein kinase that controls the endocycle, is a target of let-7. Notably, the mutation of cdc7 in the fat body resulted in growth defects. Overall, our findings revealed a novel role of let-7 in the control of endoreduplication-related growth during larval-prepupal transition in Drosophila.

Helicobacter pylori promotes hepatic fibrosis in the animal model.

Helicobacter pylori infection has been reported to be very common in patients with chronic liver diseases, including cirrhosis. To elucidate the pathological effect of H. pylori infection on the progression of hepatic fibrosis, C57BL/6 mice and Sprague-Dawley rats were orally inoculated with H. pylori, and hepatic fibrosis was induced with carbon tetrachloride (CCl(4)) administration. We observed the histopathological changes and the presence of H. pylori genes by PCR in the liver. Significant increase in the fibrotic score as well as in serum alanine aminotransferase and aspartate aminotransferase levels was shown in the CCl(4)+H. pylori group compared with that in the CCl(4)-treated group. Compared with the CCl(4)-treated group, alpha-smooth muscle actin and transforming growth factor-beta1 were enhanced; however, senescence marker protein-30, a multifunctional protein protecting hepatocytes against oxidative stress and apoptosis, was suppressed in the CCl(4)+H. pylori group. The 16S rRNA (400 bp) was demonstrated by PCR for H. pylori genes from genomic DNA extracted from the liver, and H. pylori-infected mice showed 93.8% (15 of 16) seropositivity by contrast with seronegativity in all H. pylori-noninfected mice. In addition, immunohistochemical study against H. pylori showed positive antigen fragments in the liver of the infected groups. Consequently, our data suggest that H. pylori infection could be an important contributing infectious factor to the development of liver cirrhosis.

Multiple urogenital abnormalities in a Persian cat.

A 1.5-year-old female Persian cat was presented for inappetence and azotemia. Ultrasonography and urography revealed multiple abnormalities involving the genitourinary tract, including agenesis of the right kidney and ureter. Gross examination of the abnormal uterus revealed segmental aplasia of right caudal uterine horn causing cranial distension with fluid, a normal left uterine horn, and both normal ovaries. Microscopically, endometrial glands of the right uterine horn were markedly decreased in number. The right uterine horn was hemorrhagic suggesting estrus. This is the first report of this combination of urinary and uterus abnormalities in the veterinary literature.

Eosinophilic myositis in a slaughtered Korean native cattle.

Histopathological findings of eosinophilic myositis in the carcass of a slaughtered Korean native cow are presented. Lesions contained massive fibrous septae with vacuolar changes in some lesions, and the hypercontraction and rupturing of muscle bundles, with replacement by eosinophils. Necrosis and severe eosinophil infiltration were observed. Sarcoplasmic fragmentation and atrophy developed. Typical of granuloma, calcified myofibers were focally surrounded by macrophages and numerous inflammatory cells, and multinucleated giant cell formation was evident.

Primary biliary cirrhosis, similar to that in human beings, in a male C57BL/6 mouse infected with Helicobacter pylori.

We report a case of primary biliary cirrhosis (PBC) that occurred in a 24-month-old male C57BL/6 mouse infected with Helicobacter pylori (H. pylori). Microscopically, the portal tract in the liver showed nonsuppurative destructive cholangitis with variable cytologic distortion of the epithelial cells and peribiliary lymphoplasmacytic infiltration. Immunohistochemistry using alpha-smooth muscle actin demonstrated fibrous bands associating with the wall of vasculature. The level of serum antivacuolating toxin IgG in this mouse showed the highest value (optical density=2.1470) of the H. pylori-infected group (n=13) (optical density=1.7168+/-0.1759, mean+/-SD). Spontaneously developed PBC-like lesions in C57BL/6 mice have been reported by several authors. However, this case strikingly resembles human PBC with its characterized histological features. Therefore, we propose that the increase in vacuolating toxin caused by H. pylori infection may be related to the development of PBC by molecular mimicry.

Discoid lupus erythematosus (DLE) in a Spitz dog.

A 3-year-old, female Spitz, was presented due to lack of response to therapies with a 6-month history of skin lesions characterized by diffuse erythema and scaling on the dorsal trunk. Physical examination revealed the dog was active and healthy. Skin culture isolated no fungus. Histological examination of skin biopsy specimens revealed interface dermatitis with hydropic degeneration of the basal layers, predominant plasmacytic perivascular accumulation in the dermis, and intensive plasma cell-rich interface mural folliculitis. Moderate CD3-positive lymphocytes infiltrated the superficial dermis. This report may provide unique information of canine discoid lupus erythematosus in an unusual breed with atypical cutaneous lesions.

Hepatoprotective effect of Arazyme on CCl4-induced acute hepatic injury in SMP30 knock-out mice.

Arazyme is a novel protease produced by the HY-3 strain of Aranicola proteolyticus, which is a Gram-negative aerobic bacterium that has been isolated from the intestine of the spider Nephila clavata. This study focused on the hepatoprotective effect of Arazyme on carbon tetrachloride (CCl4)-induced acute hepatic injury in senescence marker protein 30 (SMP30) knock-out (KO) mice and SMP30 wild-type (WT) mice. WT mice and SMP30 KO mice were divided into eight groups as follows: (i) two negative control groups (G1, G5) which were treated with a single intraperitoneal (i.p.) olive oil injection. (ii) Two positive control groups (G2, G6) which received a single i.p. CCl4 (0.4mL/kg) injection. (iii) Two vitamin C-treated groups (G3, G7) which received a single oral administration of vitamin C (100mg/kg) and were injected with a single i.p. CCl4 (0.4mL/kg). (iv) Two Arazyme-treated groups (G4, G8) which received a single oral administration of Arazyme (500mg/kg) and were injected with a single i.p. CCl4 (0.4mL/kg). Through present study, we could find that Arazyme-treated groups showed decreased degree of liver injury, increased expression of SMP30, decreased expression of phospho-Smad3 (p-Smad3), elevated expression of antioxidant proteins including sorbitol dehydrogenase, dihydropteridine reductase (DHPR), dehydrofolate reductase (DHFR), NADH dehydrogenase, glutathione S-transferase kappa 1 (GSTK1) and phospholipid hydroperoxide glutathione peroxidase (PHGPx) compared with non-Arazyme-treated groups. Therefore, it is concluded that Arazyme plays a significant role in protecting injured hepatocytes by increasing the expression of SMP30, inhibiting the transforming growth factor-beta (TGF-beta)/Smad pathway and elevating the expression of antioxidant proteins.

Differential regulation of ERK1/2 and p38 MAP kinases in VacA-induced apoptosis of gastric epithelial cells.

Helicobacter pylori vacuolating cytotoxin A (VacA) has been considered as an apoptosis-inducing factor. Here, we investigated the mechanism of VacA-induced apoptosis in relation to the defense mechanism and MAP kinases pathway in gastric epithelial cells. AGS cells exposed to enriched VacA extracts affected the level of SOD-1 and villin. We further investigated the role of VacA in those inductions using a functional recombinant VacA (rVacA). Activation of p38 MAPK and Bax dimerization by rVacA were increased in a dose-dependent manner. rVacA-induced ERK1/2 MAPK activation was maximal at 30 min and 4 h and 1-4 microg/ml of rVacA. rVacA-induced SOD-1 expression was considerably diminished by inhibiting ERK1/2 MAPK and it was slightly increased by inhibiting p38 MAPK. rVacA increased or decreased villin expression depending on dose and exposure time and its expression was mainly appeared in the contractile actin ring of the dividing cells. Despite its cytoprotective effect, SB-203580, a p38 inhibitor, was unlikely to reduce VacA-induced Bax dimerization and rather inhibited villin and Bcl2 expression, indicating that p38 may also play a role in cell proliferation or differentiation for survival after VacA intoxication. Furthermore, p38 inhibitor accelerated rVacA-induced cell death after exposure of AGS cells to H(2)O(2) but ERK1/2 inhibitor protected cells from H(2)O(2) insult. These results suggest that SOD-1 and villin are expressed differentially upon VacA insult depending on dose and exposure time via ERK and p38 MAP kinases; decrease in SOD-1 and villin expression coupled with Bax dimerization leads to apoptosis of gastric epithelial cells.

Cytotoxic effects of the conjugated linoleic acid isomers t10c12, c9t11-CLA and mixed form on rat hepatic stellate cells and CCl4-induced hepatic fibrosis.

Rat hepatic stellate cells (HSC-T6) were incubated for 24 h with 10-180 microM of t10c12 (98%), c9t11 (96%) and a mixed form (c9,t11:t10,c12; 41%:44%) of conjugated linoleic acid (CLA). The MTS dye reduction was measured to verify cell viability in a dose-dependent manner. Among the three CLAs, c9,t11-CLA exhibited the most intense cytotoxic effect on HSCs, the survival rate of which was reduced to 60% under 80 microM of treatment, while cell survival was slightly affected by the mixed form. Three CLA-induced cell deaths were determined by measuring DNA fragmentation using 4',6-diamidino-2-phenylindole staining. The degrees of DNA fragmentation were the most severe in HSC treated with 80 microM of c9,t11-CLA. The mitogen-activated protein kinase/extracellular signal-regulated kinase-kinase and mitogen-activated or extracellular signal-regulated protein kinase (MEK) 1 and 2 were not activated in the t10,c12-CLA treatment. This suggests that the MEK-dependent apoptosis signal is crucial in HSC, which is induced by c9,t11 and mixed CLA. In order to evaluate the protective effect of CLA on carbon tetrachloride (CCl4)-induced hepatic fibrosis in vivo, animals were treated with 10% CCl4 to induce hepatic fibrosis during all experimental periods. Rats were divided into two treatment groups: (1) control diet with tap water ad libitum (n=15) and (2) 1% CLA diet with tap water ad libitum (n=15). In the CLA-supplemented rat livers, alpha-smooth muscle actin-positive cells were significantly reduced around the portal vein. In addition, collagen fibers were not detected in the CLA-treated group. These results suggest that 9c,11t-CLA influences cytotoxic effect on HSC in an MEK-dependent manner and preserving liver from fibrosis.

Multiple intestinal lymphomatous polyposis in a Jindo dog.

A male, 5-year-old Jindo dog underwent enterectomy and enteroanastomosis due to ileus of the intestine at a local veterinary hospital. Grossly, the excised intestine showed markedly thickened multinodular masses in the serosal layer of the upper part, and soft-to-firm, cream-colored neoplastic masses that displayed extensive nodular mucosal protuberances into the lumen. The neoplastic masses were filled with large round cells that were ovoid in shape and they had pale and/or hyperchromatic nuclei. The neoplastic cells had mainly infiltrated into the mucosal and submucosal layers, and they had diffusely invaded the muscular and serosal layers. Therefore, the diagnosis of canine multiple intestinal malignant lymphomatous polyposis was made based on the gross and histopathological findings. The origin of these tumor cells was determined to be B-cells since they were positive for anti-CD20.

Kinetics of MMP-1 and MMP-3 produced by mast cells and macrophages in liver fibrogenesis of rat.

BACKGROUND: The involvement of whether macrophages and mast cells in the kinetics of matrix metalloproteinases-1 (MMP-1), MMP-3 and MMP-9, tissue inhibitors of metalloproteinases-1 (TIMP-1) and TIMP-2 in hepatic fibrosis/cirrhosis was examined. MATERIALS AND METHODS: The MMPs and TIMPs were examined by histopathology, immunohistochemistry and immunoblotting using carbon tetrachloride-induced fibrotic rat liver. RESULTS: MMP-1 increased in proportion to the development of fibrosis and reached maximum at week 14. In the first four weeks, MMP-3 expression was mainly observed in many hepatocytes. At week 8, the macrophages in the fibrous septa, as well as hepatocytes, expressed MMP-3. TIMP-1 and -2 progressively increased throughout the experimental periods. The MMP-1 expression in the mast cells, however, did not decrease the degree of liver cirrhosis. CONCLUSION: MMP-1, TIMP-1 and -2 expressions increased in the late stages of fibrosis and cirrhosis. During recovery, the MMP-3 expression of macrophages greatly increased in the unresolved fibrous septa.

Canine renal failure syndrome in three dogs.

Three dead dogs were brought to the College of Veterinary Medicine, Kyungpook National University for study. Clinically, all the dogs showed emaciation, anorexia, depression, hemorrhagic vomiting and diarrhea for 7-10 days before death. All the clinical signs were first noted for about one month after feeding the dogs with commercial diets. At necropsy, all 3 dogs had severe renal damage with the same green-yellowish colored nephroliths in the renal pelvis. They also showed systemic hemorrhage and calcification of several organs, which might have been induced by uremia. Microscopically, necrosis, calcification and calculi were detected in the renal tubules, and especially in the proximal convoluted tubules and collecting ducts of the kidney. These findings were supportive of a mycotoxic effect, and especially on their kidneys. However, the precise cause of the toxic effect in these cases of canine renal failure could not be determined.

Expression of cytokeratins 8 and 18 on Mallory body and oval cell in rats during hepatic fibrosis.

BACKGROUND: The aim of this study was to determine the induction and distribution of Mallory body (MB) and oval cells in carbon-tetrachloride (CCl4)-induced rat liver fibrosis. MATERIALS AND METHODS: MBs and oval cells expressing cytokeratins (CKs) 8 and 18 were monitored by immuno-histochemistry and immunoblotting. RESULTS: MBs were mainly detected within hepatocytes near the fibrotic areas, and oval cells were located along or in the fibrotic areas. Both MBs and oval cells increased in size and number in the development of fibrosis. At cirrhotic liver, most of the oval cells were located in the fibrous septa and around newly formed bile ductules. Moreover, as hepatic injuries developed into fibrosis, a much more prominent single band of CK18 was detected. CONCLUSION: The occurrence and distribution of MB and oval cells in CCl4-induced rat liver fibrosis are reported. This represents the first CCl4 experimental in vivo model of MB induction, which will be useful for further investigations on the pathogenesis of MB.

Alterations of mast cells and TGF-beta1 on the silymarin treatment for CCl(4)-induced hepatic fibrosis.

AIM: Silymarin is a potent antioxidant, antiinflammatory and anti-fibrogenic agent in the liver, which is mediated by alteration of hepatic Kupffer cell function, lipid peroxidation, and collagen production. Especially, in hepatic fibrogenesis, mast cells are expressed in chronic inflammatory conditions, and promote fibroblast growth and stimulate production of the extracellular matrix by hepatic stellate cells. METHODS: We examined the inhibitory mechanism of silymarin on CCl(4)-induced hepatic cirrhosis in rats. At 4, 8, and 12 wk, liver tissues were examined histopathologically for fibrotic changes produced by silymarin treatment. RESULTS: In the silymarin with CCl(4)-treated group, increase of hepatic stellate cells and TGF-beta1 production were lower than in the CCl(4)-treated group at early stages. Additionally, at the late fibrogenic stage, expressions of TGF-beta1 were weaker and especially not expressed in hepatocytes located in peripheral areas. Moreover, the number of mast cell in portal areas gradually increased and was dependent on the fibrogenic stage, but those of CCl(1)+silymarin-treated group decreased significantly. CONCLUSION: Anti-fibrotic and antiinflammatory effects of silymarin were associated with activation of hepatic stellate cells through the expression of TGF-beta1 and stabilization of mast cells. These results suggest that silymarin prevent hepatic fibrosis through suppression of inflammation and hypoxia in the hepatic fibrogenesis.