Kentaro Katayama

Hyaloklossia Labbé ,1896 (Alveolata: Apicomplexa) is a monotypic genus of renal coccidia found in anurans, particularly in the edible frog Pelophylax kl. esculentus (Amphibia: Anura: Ranidae), distributed in different parts of Europe. Here we propose a new Hyaloklossia species from the Tokyo daruma pond frog, Pelophylax porosus porosus. The coccidium detected in the renal tissue of P. p. porosus shared some morphological characteristics with the type species, Hyaloklossia lieberkuehni (Labbé, 1894), reported from P. kl. esculentus. However, in addition to size differences in several oocyst and sporocyst features between these parasites, phylogenetic analysis of gene fragments from two nuclear ribosomal loci and the mitochondrial cytochrome c oxidase subunit 1, exposed distinct genetic differences between H. lieberkuehni and our new species. Although our analysis validated the monophyly of Hyaloklossia with some members of the Toxoplasmatinae Biocca, 1957, Cystoisosporinae Frenkel et al., 1987, and Eumonosporinae Chou et al., 2021 (Sarcocystidae Poche, 1913), comparison of genetic differences between Hyaloklossia species from P. p. porosus and H. lieberkuehni revealed the presence of a greater number of polymorphisms than that observed when comparing inter-species (Heydornia spp., Besnoisita spp.) or inter-genus (Toxoplasma vs. Neospora, Neospora vs. Hammondia, and Neospora vs. Heydornia) variabilities among members of the Sarcocystidae. This indicates that Hyaloklossia, as re-erected and defined by Modrý et al. (2001, Int. J. Syst. Evol. Microbiol. 51, 767-772), with its homoxenous life cycle, requires placement in its own subfamily. Thus, we propose a new subfamily, Hyaloklossiinae n. subfam., to accommodate two species, H. lieberkuehni from Europe and Hyaloklossia kasumienesis n. sp. which we describe here from P. p. porosus in Japan.

The kidneys participate in the regulation of systemic glucose metabolism via gluconeogenesis, insulin degradation, and the tubular reabsorption of glucose. The present study characterized rats from a strain of a novel type 2 diabetes model with enlarged kidneys (DEK). Histological and biochemical analyses of DEK rats were performed to assess the relationships between their kidneys and hyperglycemia. The kidney weight of diabetic DEK (DEK-DM) gradually increased over time from the onset of diabetes, with the glomerular number being higher in DEK-DM than in normal DEK (DEK-cont). A positive correlation between blood glucose level and kidney weight was observed in DEK-DM. The similar glomerular size and single glomerular creatinine clearance in DEK-cont and DEK-DM indicated that glomerular hypertrophy and hyperfiltration were not involved in the renal enlargement. Uninephrectomy (1/2Nx) in DEK-DM resulted in a reduction in blood glucose level at 7-28 post-operation days, with this concentration remaining lower than in Sham group until 84 days post-operation. 1/2Nx also improved systemic conditions, including reduced body weight gain, polyuria, polydipsia, and hyperphagia. Plasma concentrations of Na, total cholesterol, albumin, and total protein were higher, and urinary excretion of glucose, urea nitrogen, and proteins were lower, in the 1/2Nx than in the Sham group. Remnant kidney weight was two-fold higher in the 1/2Nx than in the Sham group 84 days later. In addition, 1/2Nx resulted in renal tubular dilatation but not in the progression of fibrosis or glomerular lesions. Taken together, these findings indicate that enlarged kidneys were associated with the onset of diabetes and with the resistance to diabetic nephropathy in DEK-DM.

A well-known putative tumor suppressor WW domain-containing oxidoreductase (Wwox) is highly expressed in hormonally regulated tissues and is considered important for the normal development and function of reproductive organs. In this study, we investigated the cellular and subcellular localization of Wwox in normal testes during postnatal days 0-70 using Western blotting and immunohistochemistry. Wwox is expressed in testes at all ages. Immunohistochemistry showed that fetal-type and adult-type Leydig cells, immature and mature Sertoli cells, and germ cells (from gonocytes to step 17 spermatids) expressed Wwox except peritubular myoid cells, step 18-19 spermatids, and mature sperm. Wwox localized diffusely in the cytoplasm with focal intense signals in all testicular cells. These signals gradually condensed in germ cells with their differentiation and colocalized with giantin for cis-Golgi marker and partially with golgin-97 for trans-Golgi marker. Biochemically, Wwox was detected in isolated Golgi-enriched fractions. But Wwox was undetectable in the nucleus. This subcellular localization pattern of Wwox was also confirmed in single-cell suspension. These findings indicate that Wwox is functional in most cell types of testis and might locate into Golgi apparatus via interaction with Golgi proteins. These unique localizations might be related to the function of Wwox in testicular development and spermatogenesis.

BACKGROUND: Sodium-glucose cotransporter 2 (SGLT2) inhibitors are widely used to reduce hyperglycemia. The present study investigated the effects of a SGLT2 inhibitor, empagliflozin, on hyperglycemia in a novel rat model of non-obesity type 2 diabetes with enlarged kidney (DEK). METHODS: Male DEK rats with non-fasting blood glucose concentrations ≤300 mg/dl and >300 mg/dl were classified as nondiabetic and diabetic, respectively. Groups of nondiabetic (control) and diabetic (DM-cont) rats were fed standard chow for 12 weeks, whereas another group of diabetic (DM-empa) rats was fed standard chow containing empagliflozin (300 mg/kg/day) for 12 weeks. Blood glucose, body weight, glucose tolerance, food and water intake, urinary volume, plasma and urinary biochemical parameters, and bone mineral density were measured, and their kidneys and pancreas histologically analyzed. RESULTS: Treatment with empagliflozin reduced blood glucose concentration and food intake in diabetic rats, but inhibited loss of adeps renis and led to body weight gain. Empagliflozin attenuated polyuria and polydipsia but increased plasma concentrations of total cholesterol, sodium and total protein toward normal level. Empagliflozin also significantly reduced urinary excretion of proteins and electrolytes and restored bone mineral density and plasma concentrations of valine and isoleucine to normal levels. Moreover, dilation of renal tubules and kidney enlargement were not attenuated in the DM-empa group. CONCLUSION: The response of DEK rats to empagliflozin differed from that of other diabetic animal models, suggesting that DEK rats have unique characters for studying and evaluating the multiple biological effects of SGLT2 inhibitors. These findings also indicted that empagliflozin could ameliorate systemic metabolism and improve renal tubule function in diabetic condition.