Neonatal lethality of mouse A/J-7SM consomic strain is caused by an insertion mutation in the Dchs1 gene.

Homosomic mice of the A/J-7SM consomic mouse strain that introduced the entire chromosome 7 (Chr 7) of SM/J into the A/J strain exhibited neonatal lethality. We tentatively maintained segregating inbred strains (A/J-7ASM and A/J-7DSM) in which the central portion of Chr 7 was heterozygous for the A/J and SM/J strains, and the centromeric and telomeric sides of Chr 7 were homozygous for the SM/J strain, instead of the A/J-7SM strain. Based on the chromosomal constitution of Chr 7 in A/J-7ASM and A/J-7DSM mice, the causative gene for neonatal lethality in homosomic mice was suggested to be located within an approximately 1.620 Mb region between D7Mit125 (104.879 Mb) and D7Mit355 (106.499 Mb) on Chr 7. RT-PCR analysis revealed that homosomic mice lacked dachsous cadherin-related 1 (Dchs1), which is located within the D7Mit125 to D7Mit355 region and functions in the regulation of planar cell polarity. Screening for mutations in Dchs1 indicated that homosomic mice possessed an early transposable (ETn)-like sequence in intron 1 of Dchs1. Moreover, an allelism test between Dchs1 ETn-like-insertion alleles detected in homosomic mice and CRISPR/Cas9-induced Dchs1 deletion alleles revealed that Dchs1 is a causative gene for neonatal lethality in homosomic mice. Based on these results, we concluded that in the A/J-7SM strain, ETn-like elements were inserted into intron 1 of SM/J-derived Dchs1 during strain development, which dramatically reduced Dchs1 expression, thus resulting in neonatal lethality in homosomic mice. Additionally, it was suggested that the timing of lethality in Dchs1 mutant mice is influenced by the genetic background.

Type 2 diabetes susceptibility genes on mouse chromosome 11 under high sucrose environment.

BACKGROUND: Both genetic and environmental factors contribute to type 2 diabetes development. We used consomic mice established from an animal type 2 diabetes model to identify susceptibility genes that contribute to type 2 diabetes development under specific environments. We previously established consomic strains (C3H-Chr 11NSY and C3H-Chr 14NSY) that possess diabetogenic Chr 11 or 14 of the Nagoya-Shibata-Yasuda (NSY) mouse, an animal model of spontaneous type 2 diabetes, in the genetic background of C3H mice. To search genes contribute to type 2 diabetes under specific environment, we first investigated whether sucrose administration deteriorates type 2 diabetes-related traits in the consomic strains. We dissected loci on Chr 11 by establishing congenic strains possessing different segments of NSY-derived Chr 11 under sucrose administration. RESULTS: In C3H-Chr 11NSY mice, sucrose administration for 10 weeks deteriorated hyperglycemia, insulin resistance, and impaired insulin secretion, which is comparable to NSY mice with sucrose. In C3H-Chr 14NSY mice, sucrose administration induced glucose intolerance, but not insulin resistance and impaired insulin secretion. To dissect the gene(s) existing on Chr 11 for sucrose-induced type 2 diabetes, we constructed four novel congenic strains (R1, R2, R3, and R4) with different segments of NSY-derived Chr 11 in C3H mice. R2 mice showed marked glucose intolerance and impaired insulin secretion comparable to C3H-Chr 11NSY mice. R3 and R4 mice also showed impaired insulin secretion. R4 mice showed significant decreases in white adipose tissue, which is in the opposite direction from parental C3H-Chr 11NSY and NSY mice. None of the four congenic strains showed insulin resistance. CONCLUSIONS: Genes on mouse Chr 11 could explain glucose intolerance, impaired insulin secretion, insulin resistance in NSY mice under sucrose administration. Congenic mapping with high sucrose environment localized susceptibility genes for type 2 diabetes associated with impaired insulin secretion in the middle segment (26.0-63.4 Mb) of Chr 11. Gene(s) that decrease white adipose tissue were mapped to the distal segment of Chr 11. The identification of diabetogenic gene on Chr 11 in the future study will facilitate precision medicine in type 2 diabetes by controlling specific environments in targeted subjects with susceptible genotypes.

Improved technique for sheath supported contralateral limb gate cannulation in endovascular abdominal aortic aneurysm repair.

Background: To present a technique of sheath supported contralateral limb gate (CLG) cannulation of modular bifurcated stent-graft in endovascular abdominal aortic repair. Materials and methods: After totally percutaneous bilateral femoral access, the 9F introducer sheath is exchanged to a 30 cm 12 fr introducer sheath over a stiff wire contralateral to the intended main stent-graft insertion side and advanced into the aorta below the lowest renal artery. Parallel to the stiff wire within the sheath an additional standard J-tip guidewire with a 5 fr Pigtail angiographic catheter is advanced to the level of the renal arteries. After main body deployment, the 12 fr introducer sheath and J-tip wire with pigtail catheter are retracted until the CLG opening level, maintaining the stiff "buddy" wire in position to support the 12 fr sheath, maintaining its distal opening close to the contralateral gate opening to achieve easy cannulation. Results: Retrospective analysis of video archive from July 2016 to February 2018 evidenced 55 recorded EVAR cases. All CLG cannulations were obtained with Standard J-tip or Terumo Glidewire wires and with Pig-Tail or Berenstein catheters. Technical success was 100 %. Mean fluoroscopy time to accomplish CLG cannulation was 37.6 33 (range 1-105) seconds. The aortic carrefour angulation on coronal axis strongly correlates with cannulation time p = <.001, with longer cannulation time for higher carrefour angulations on coronal axis (Pearson correlation coefficient 0.47). Conclusions: The use of 12 fr sheath with parallel wire introduction technique, appears to be a safe and reliable tool to facilitate CLG cannulation during EVAR procedures.

Congenic mapping and candidate gene analysis for streptozotocin-induced diabetes susceptibility locus on mouse chromosome 11.

Streptozotocin (STZ) has been widely used to induce diabetes in rodents. Strain-dependent variation in susceptibility to STZ has been reported; however, the gene(s) responsible for STZ susceptibility has not been identified. Here, we utilized the A/J-11SM consomic strain and a set of chromosome 11 (Chr. 11) congenic strains developed from A/J-11SM to identify a candidate STZ-induced diabetes susceptibility gene. The A/J strain exhibited significantly higher susceptibility to STZ-induced diabetes than the A/J-11SM strain, confirming the existence of a susceptibility locus on Chr. 11. We named this locus Stzds1 (STZ-induced diabetes susceptibility 1). Congenic mapping using the Chr. 11 congenic strains indicated that the Stzds1 locus was located between D11Mit163 (27.72 Mb) and D11Mit51 (36.39 Mb). The Mpg gene, which encodes N-methylpurine DNA glycosylase (MPG), a ubiquitous DNA repair enzyme responsible for the removal of alkylated base lesions in DNA, is located within the Stzds1 region. There is a close relationship between DNA alkylation at an early stage of STZ action and the function of MPG. A Sanger sequence analysis of the Mpg gene revealed five polymorphic sites in the A/J genome. One variant, p.Ala132Ser, was located in a highly conserved region among rodent species and in the minimal region for retained enzyme activity of MPG. It is likely that structural alteration of MPG caused by the p.Ala132Ser mutation elicits increased recognition and excision of alkylated base lesions in DNA by STZ.

Genetic dissection of the fatty liver QTL Fl1sa by using congenic mice and identification of candidate genes in the liver and epididymal fat.

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) is a multifactorial disease caused by interactions between environmental and genetic factors. The SMXA-5 mouse is a high-fat diet-induced fatty liver model established from SM/J and A/J strains. We have previously identified Fl1sa, a quantitative trait locus (QTL) for fatty liver on chromosome 12 (centromere-53.06 Mb) of SMXA-5 mice. However, the chromosomal region containing Fl1sa was too broad. The aim of this study was to narrow the Fl1sa region by genetic dissection using novel congenic mice and to identify candidate genes within the narrowed Fl1sa region. RESULTS: We established two congenic strains, R2 and R3, from parental A/J-12SM and A/J strains. R2 and R3 strains have genomic intervals of centromere-29.20 Mb and 29.20-46.75 Mb of chromosome 12 derived from SM/J, respectively. Liver triglyceride content in R2 and R3 mice was significantly lower than that in A/J mice fed with a high-fat diet for 7 weeks. This result suggests that at least one of the genes responsible for fatty liver exists within the two chromosomal regions centromere-29.20 Mb (R2) and 29.20-46.75 Mb (R3). We found that liver triglyceride accumulation is inversely correlated with epididymal fat weight among the parental and congenic strains. Therefore, the ectopic fat accumulation in the liver may be due to organ-organ interactions between the liver and epididymal fat. To identify candidate genes in Fl1sa, we performed a DNA microarray analysis using the liver and epididymal fat in A/J and A/J-12SM mice fed with a high-fat diet for 7 weeks. In epididymal fat, mRNA levels of Zfp125 (in R2) and Nrcam (in R3) were significantly different in A/J-12SM mice from those in A/J mice. In the liver, mRNA levels of Iah1 (in R2) and Rrm2 (in R2) were significantly different in A/J-12SM mice from those in A/J mice. CONCLUSIONS: In this study, using congenic mice analysis, we narrowed the chromosomal region containing Fl1sa to two regions of mouse chromosome 12. We then identified 4 candidate genes in Fl1sa: Iah1 and Rrm2 from the liver and Zfp125 and Nrcam from epididymal fat.

Detection of differentially expressed candidate genes for a fatty liver QTL on mouse chromosome 12.

BACKGROUND: The SMXA-5 mouse is an animal model of high-fat diet-induced fatty liver. The major QTL for fatty liver, Fl1sa on chromosome 12, was identified in a SM/J × SMXA-5 intercross. The SMXA-5 genome consists of the SM/J and A/J genomes, and the A/J allele of Fl1sa is a fatty liver-susceptibility allele. The existence of the responsible genes for fatty liver within Fl1sa was confirmed in A/J-12(SM) consomic mice. The aim of this study was to identify candidate genes for Fl1sa, and to investigate whether the identified genes affect the lipid metabolism. RESULTS: A/J-12(SM) mice showed a significantly lower liver triglyceride content compared to A/J mice when fed the high-fat diet for 7 weeks. We detected differences in the accumulation of liver lipids in response to the high-fat diet between A/J and A/J-12(SM) consomic mice. To identify candidate genes for Fl1sa, we performed DNA microarray analysis using the livers of A/J-12(SM) and A/J mice fed the high-fat diet. The mRNA levels of three genes (Iah1, Rrm2, Prkd1) in the chromosomal region of Fl1sa were significantly different between the strains. Iah1 mRNA levels in the liver, kidney, and lung were significantly higher in A/J-12(SM) mice than in A/J mice. The hepatic Iah1 mRNA level in A/J-12(SM) mice was 3.2-fold higher than that in A/J mice. To examine the effect of Iah1 on hepatic lipid metabolism, we constructed a stable cell line expressing the mouse Iah1 protein in mouse hepatoma Hepa1-6 cells. Overexpression of Iah1 in Hepa1-6 cells suppressed the mRNA levels of Cd36 and Dgat2, which play important roles in triglyceride synthesis and lipid metabolism. CONCLUSIONS: These results demonstrated that Fl1sa on the proximal region of chromosome 12 affected fatty liver in mice on a high-fat diet. Iah1 (isoamyl acetate-hydrolyzing esterase 1 homolog) was identified as one of the candidate genes for Fl1sa. This study revealed that the mouse Iah1 gene regulated the expression of genes related to lipid metabolism in the liver.

Long-term results of simplified frozen elephant trunk technique in complicated acute type A aortic dissection: A case-control study.

AIM: To describe the long-term experience of a simplified frozen elephant trunk technique (sFETT) used in complicated acute type A aortic dissection (AAAD) treatment. METHODS AND RESULTS: Between January 2001 and December 2012, 34 patients (mean age 59.9 ± 11.0 years) with complicated AAAD (DeBakey I) underwent an emergency surgery including sFETT. sFETT consisted in gluing the dissected aortic arch wall layers with gelatine-resorcinol adhesive and video-assisted antegrade open arch aortic stent-graft deployment in the arch or proximal descending aorta. In addition to sFETT, the aortic root was addressed with standard techniques. A 30-day mortality was 14.7% (five patients) due to bleeding (1), multiple organ failure (2), and colon ischemia (2). Postoperative morbidity included neurological (2), renal (1) and cardio-pulmonary complications (4), as well as wound infection (1). Mean follow-up was 74.4 ± 45.0 months. Actual survival rates were 73.5% at 1 year, 70.2% at 5 years, and 58.5% at 13 years of follow-up. Six patients died during long-term follow-up from heart failure (1) and unknown reasons (5). Five patients required reoperation for aortic arch (3) or aorto-iliac (2) progression of aneurysm during the mid- and long-term follow-up. The remaining patients showed favorable evolution of the dissected aorta with false lumen occlusion in most cases and stable aortic diameters. CONCLUSIONS: In AAAD patients, sFETT as used in our series is an easy and safe technique to repair the aortic arch. Long-term results after sFETT showed false lumen occlusion and stable aortic diameter in up to 13 years of follow-up.

Genetic dissection of susceptibility genes for diabetes and related phenotypes on mouse chromosome 14 by means of congenic strains.

BACKGROUND: A susceptibility locus, Nidd2n, for type 2 diabetes has been mapped to mouse chromosome 14 (Chr 14) and confirmed using the consomic strain (C3H-Chr 14NSY) of the Nagoya-Shibata-Yasuda (NSY) mouse, an animal model of spontaneous type 2 diabetes. The aim of this study was to localize and characterize Nidd2n. RESULTS: We constructed two novel congenic strains homozygous for different segments of NSY-Chr 14 on the control C3H/HeNcrj (C3H) background: R1 (C3H.NSY-(D14Mit206-D14Mit5)) possesses the proximal and middle segment, and R2 (C3H.NSY-(D14Mit206-D14Mit186)) possesses the most proximal segment of NSY-Chr 14. Diabetes-related phenotypes were studied in comparison with those of consomic C3H-Chr 14NSY (R0) and parental NSY and C3H strains. Congenic R1 and R2 showed significantly higher post-challenge glucose than that in C3H mice. Fasting glucose, in contrast, was significantly lower in R1 and R2 than in C3H mice. Insulin sensitivity was significantly impaired in R1 and R2 compared to C3H mice. R2 showed significantly higher body weight and fat-pad weight than those in C3H and R1. Leptin level was significantly higher in R0, R1 and R2 than in C3H mice, with R2 showing the highest level, similar to that in NSY mice. Serum adiponectin level was significantly lower in R0, R1 and R2 than in C3H mice, while it was significantly higher in NSY than in C3H mice. CONCLUSIONS: These data indicate that Chr 14 harbors multiple genes for diabetes-related phenotypes. The original Nidd2n, which is located in the middle region of Chr 14, was divided into two segments; Nidd2.1n in proximal Chr 14 and Nidd2.2n in distal Chr 14. Nidd2.1n contributes to post-challenge hyperglycemia, insulin resistance and adiposity. Nidd2.2n contributes to fasting as well as post-challenge hyperglycemia and insulin resistance. Adp1n, which contributes to decreased adiposity and increased insulin sensitivity, rather than a diabetogenic gene, was mapped in the middle segment.

Ascorbic acid deficiency decreases hepatic cytochrome P-450, especially CYP2B1/2B2, and simultaneously induces heme oxygenase-1 gene expression in scurvy-prone ODS rats.

The mechanisms underlying the decrease in hepatic cytochrome P-450 (CYP) content in ascorbic acid deficiency was investigated in scurvy-prone ODS rats. First, male ODS rats were fed a diet containing sufficient ascorbic acid (control) or a diet without ascorbic acid (deficient) for 18 days, with or without the intraperitoneal injection of phenobarbital. Ascorbic acid deficiency decreased hepatic microsomal total CYP content, CYP2B1/2B2 protein, and mitochondrial cytochrome oxidase (COX) complex IV subunit I protein, and simultaneously increased heme oxygenase-1 protein in microsomes and mitochondria. Next, heme oxygenase-1 inducers, that is lipopolysaccharide and hemin, were administered to phenobaribital-treated ODS rats fed sufficient ascorbic acid. The administration of these inducers decreased hepatic microsomal total CYP content, CYP2B1/2B2 protein, and mitochondrial COX complex IV subunit I protein. These results suggested that the stimulation of hepatic heme oxygenase-1 expression by ascorbic acid deficiency caused the decrease in CYP content in liver.

FcRY is a key molecule controlling maternal blood IgY transfer to yolks during egg development in avian species.

Maternal immunoglobulin transfer plays a key role in conferring passive immunity to neonates. Maternal blood immunoglobulin Y (IgY) in avian species is transported to newly-hatched chicks in two steps: 1) IgY is transported from the maternal circulation to the yolk of maturing oocytes, 2) the IgY deposited in yolk is transported to the circulation of the embryo via the yolk sac membrane. An IgY-Fc receptor, FcRY, is involved in the second step, but the mechanism of the first step is still unclear. We determined whether FcRY was also the basis for maternal blood IgY transfer to the yolk in the first step during egg development. Immunohistochemistry revealed that FcRY was expressed in the capillary endothelial cells in the internal theca layer of the ovarian follicle. Substitution of the amino acid residue in Fc region of IgY substantially changed the transport efficiency of IgY into egg yolks when intravenously-injected into laying quail; the G365A mutant had a high transport efficiency, but the Y363A mutant lacked transport ability. Binding analyses of IgY mutants to FcRY indicated that the mutant with a high transport efficiency (G365A) had a strong binding activity to FcRY; the mutants with a low transport efficiency (G365D, N408A) had a weak binding activity to FcRY. One exception, the Y363A mutant had a remarkably strong binding affinity to FcRY, with a small dissociation rate. The injection of neutralizing FcRY antibodies in laying quail markedly reduced IgY uptake into egg yolks. The neutralization also showed that FcRY was engaged in prolongation of half-life of IgY in the blood; FcRY is therefore a multifunctional receptor that controls avian immunity. The pattern of the transport of the IgY mutants from the maternal blood to the egg yolk was found to be identical to that from the fertilized egg yolk to the newly-hatched chick blood circulation, via the yolk sac membrane. FcRY is therefore a critical IgY receptor that regulates the IgY uptake from the maternal blood circulation into the yolk of avian species, further indicating that the two steps of maternal-newly-hatched IgY transfer are controlled by a single receptor.

Carboxylation of alkynylsilanes with carbon dioxide mediated by cesium fluoride in DMSO.

The facile syntheses of a variety functionalized propiolic acids were achieved by carboxylation of alkynylsilanes with carbon dioxide mediated by cesium fluoride under ambient conditions.

Usefulness of endocytoscopy in evaluating transbronchial biopsy specimens.

BACKGROUND: Endocytoscopy (ECS) provides a magnification of approximately 450× for real-time observation of lesion nuclei. Using ECS, we aimed to evaluate whether sufficient samples for diagnosis can be obtained during bronchoscopy. We also investigated whether ECS can enable two-class diagnosis of malignant or non-malignant transbronchial biopsy specimens in real-time during bronchoscopy. METHODS: This was a single-facility, prospective, observational, ex vivo study. Forty cases with localized peripheral pulmonary lesions underwent transbronchial biopsy with endobronchial ultrasonography using a guide sheath. Each biopsy specimen was immediately observed and evaluated endocytoscopically after the collection by the bronchoscopic procedure. RESULTS: Thirty-seven cases were enrolled. The diagnostic accuracy achieved by ECS was 91.9% (34/37). The agreement rate between the endocytoscopic evaluation and pathological diagnosis of each specimen (170 specimens) was 65.3% (111/170). The median time required for endocytoscopic evaluation per specimen was 70 s. When we judged a specimen to be malignant a second time on ECS evaluations of five specimens in one case, pathologically malignant specimens were collected in 26 of 27 cases (96.3%). CONCLUSIONS: ECS with methylene blue staining may aid in the two-class diagnosis of malignant or non-malignant transbronchial biopsy specimens during bronchoscopy. This may reduce the number of tissue biopsies.

Novel loci for hyperglycemia identified by QTL mapping of longitudinal phenotypes and congenic analysis.

We previously reported that four hyperglycemia loci are located on three chromosomes in the Nagoya-Shibata-Yasuda (NSY) mouse model, commonly used to study type 2 diabetes. However, we did not search for hyperglycemia loci across all chromosomes. In this study, we performed quantitative trait loci (QTLs) mapping of longitudinal phenotypes from crosses between NSY (hyperglycemic) and C3H (normoglycemic) mice. We identified four new QTLs for hyperglycemia, namely Nidd5nsy, Nidd6nsy, Nidd1c3h, and Nidd2c3h, on Chromosome 1, 4, 10, and 13, respectively. These QTLs were associated with hyperglycemia in young mice and had attenuated effects in older mice. Nidd5nsy and Nidd6nsy were hyperglycemic with NSY alleles, and Nidd1c3h and Nidd2c3h were hyperglycemic with C3H alleles. We further bred Nidd5nsy congenic mice and demonstrated that Nidd5nsy has a strong effect on hyperglycemia when young, accompanied by insulin resistance and visceral fat accumulation. These results showed that the effects of individual QTLs strengthened or weakened with age, and that the sum of the effects of QTLs captured the age-related deterioration of glucose tolerance in individuals. Our results support the importance of longitudinal phenotypes in the genetic analysis of polygenic traits and have implications for the genetic basis and pathogenesis of type 2 diabetes in humans.

Comparison of Ultra-Magnifying Endocytoscopic and Hematoxylin-Eosin-Stained Images of Lung Specimens.

Endocytoscopy enables real-time observation of lesions at ultra-magnification. In the gastrointestinal and respiratory fields, endocytoscopic images are similar to hematoxylin-eosin-stained images. This study aimed to compare the nuclear features of pulmonary lesions in endocytoscopic and hematoxylin-eosin-stained images. We performed an endocytoscopy to observe resected specimens of normal lung tissue and lesions. Nuclear features were extracted using ImageJ. We analyzed five nuclear features: nuclear number per area, mean nucleus area, median circularity, coefficient of variation of roundness, and median Voronoi area. We conducted dimensionality reduction analyses for these features, followed by assessments of the inter-observer agreement among two pathologists and two pulmonologists to evaluate endocytoscopic videos. We analyzed the nuclear features of hematoxylin-eosin-stained and endocytoscopic images from 40 and 33 cases, respectively. Endocytoscopic and hematoxylin-eosin-stained images displayed a similar tendency for each feature, despite there being no correlation. Conversely, the dimensionality reduction analyses demonstrated similar distributions of normal lung and malignant clusters in both images, thus differentiating between the clusters. The diagnostic accuracy of the pathologists was 58.3% and 52.8% (κ-value 0.38, fair), and that of the pulmonologists was 50% and 47.2% (κ-value 0.33, fair). The five nuclear features of pulmonary lesions were similar in the endocytoscopic and hematoxylin-eosin-stained images.

Cytokine Release Syndrome More than Two Years after Pembrolizumab Introduction: A Case Report.

A 71-year-old man with advanced lung adenocarcinoma was treated with carboplatin, pemetrexed, and pembrolizumab in June 2020. Pemetrexed and pembrolizumab maintenance therapy were continued until November 2022. A fever and severe fatigue occurred in December 2022; however, the cause of the infection was inconclusive based on the patient's symptoms, imaging findings, and culture tests. Although the patient was administered antibiotics, his general condition worsened. Considering the possible diagnosis of immune-related cytokine release syndrome (CRS), the patient was administered prednisolone (1 mg/kg/day) and showed improvement. In conclusion, CRS can occur even long after the initial administration of immune checkpoint inhibitor therapy.

Prognosis of frail older patients treated with intubation and artificial ventilation for respiratory failure.

BACKGROUND: Older patients with severe respiratory failure have higher mortality rates and are more likely to experience impairments in activities of daily living (ADL). METHODS: We retrospectively reviewed patients (??75 years) who received intubation and artificial ventilation for respiratory failure at Shimane University Hospital between November 2014 and December 2020. We compared the outcomes of frail patients with those of self-sufficient patients. RESULTS: Thirty-two patients were included. ADL ability before respiratory failure was rated self-sufficient in 18 patients (self-sufficient group) and not self-sufficient in 14 patients (frail group). None of the patients in either group underwent advanced care planning prior to the onset of respiratory failure. In the self-sufficient and frail groups, the in-hospital mortality rates were 33% and 50%, and the incidence of bedridden patients at discharge was 6% and 43%, respectively. Most patients in the frail group (93%) died or were bedridden. The median hospitalization cost was JPY 2,984,000 for the self-sufficient group and JPY 3,008,000 for the frail group. CONCLUSION: The overall prognosis of frail older patients who underwent intubation and artificial ventilation was poor. When providing intensive care to such patients, it is important to carefully consider their suitability for the treatment. J. Med. Invest. 70 : 494-498, August, 2023.

C3H/HeNSlc mouse with low phospholipid transfer protein expression showed dyslipidemia.

High serum levels of triglycerides (TG) and low levels of high-density lipoprotein cholesterol (HDL-C) increase the risk of coronary heart disease in humans. Herein, we first reported that the C3H/HeNSlc (C3H-S) mouse, a C3H/HeN-derived substrain, is a novel model for dyslipidemia. C3H-S showed hypertriglyceridemia and low total cholesterol (TC), HDL-C, and phospholipid (PL) concentrations. To identify the gene locus causing dyslipidemia in C3H-S, we performed genetic analysis. In F2 intercrosses between C3H-S mice and strains with normal serum lipids, the locus associated with serum lipids was identified as 163-168 Mb on chromosome 2. The phospholipid transfer protein (Pltp) gene was a candidate gene within this locus. Pltp expression and serum PLTP activity were markedly lower in C3H-S mice. Pltp expression was negatively correlated with serum TG and positively correlated with serum TC and HDL-C in F2 mice. Genome sequencing analysis revealed that an endogenous retrovirus (ERV) sequence called intracisternal A particle was inserted into intron 12 of Pltp in C3H-S. These results suggest that ERV insertion within Pltp causes aberrant splicing, leading to reduced Pltp expression in C3H-S. This study demonstrated the contribution of C3H-S to our understanding of the relationship between TG, TC, and PL metabolism via PLTP.

Ternatin, a cyclic peptide isolated from mushroom, and its derivative suppress hyperglycemia and hepatic fatty acid synthesis in spontaneously diabetic KK-A(y) mice.

(-)-Ternatin is a highly methylated cyclic heptapeptide isolated from mushroom Coriolus versicolor. Ternatin has an inhibitory effect on fat accumulation in 3T3-L1 adipocytes. [D-Leu(7)]ternatin, a ternatin derivative, also inhibited fat accumulation in 3T3-L1 cells, although the effectiveness of [D-Leu(7)]ternatin was lower than that of ternatin. In this study, we investigated the effects of ternatin and [D-Leu(7)]ternatin on obesity and type 2 diabetes in KK-A(y) mice, an animal model for spontaneously developed type 2 diabetes. We continuously administered ternatin (8.5 or 17 nmol/day) or [D-Leu(7)]ternatin (68 nmol/day) to mice via a subcutaneous osmotic pump. Unexpectedly, neither ternatin nor [D-Leu(7)]ternatin affected body weight or adipose tissue weight in KK-A(y) mice. In contrast, it was demonstrated that both ternatin and [D-Leu(7)]ternatin suppress the development of hyperglycemia. In liver, the SREBP-1c mRNA level tended to be lower or significantly decreased in mice treated with ternatin or [D-Leu(7)]ternatin, respectively. Moreover, we found that ternatin directly lowered the SREBP-1c mRNA level in Hepa1-6 hepatocyte cells. This study showed that ternatin and [D-Leu(7)]ternatin each had a preventive effect on hyperglycemia and a suppressive effect on fatty acid synthesis in KK-A(y) mice.

Establishment of consomic strains derived from A/J and SM/J mice for genetic analysis of complex traits.

Consomic strains, in which one chromosome is derived from a donor strain and the other chromosomes are derived from the recipient strain, provide a powerful tool for the dissection of complex genetic traits. In this study we established ten consomic strains (A-2(SM), A-6(SM), A-11(SM), A-12(SM), A-13(SM), A-15(SM), A-17(SM), A-18(SM), A-19(SM), A-Y(SM)) using the SM/J strain as the donor and the A/J strain as the recipient; these are the parental strains of a set of SMXA recombinant inbred (RI) strains that we had developed previously. We analyzed body weights and blood lipid levels in the consomic and parental strains. The mean values for each trait showed a continuous range of variation in the consomic strains suggesting that they are controlled by multiple genes. We previously identified suggestive QTLs for body weight on chromosome 6 in SMXA RI strains and (SM/J × A/J)F(2) mice. The observation that the A-6(SM) consomic strain had a significantly lower mean body weight than the A/J strain supports the presence of this QTL on chromosome 6. Similarly, the higher blood triglyceride level in the A-11(SM) strain shows the existence of a previously mapped QTL on chromosome 11, and the A-12(SM) strain provides evidence of a QTL for blood total cholesterol level on chromosome 12. These consomic strains, along with the previously developed set of SMXA RI strains from A/J and SM/J mice, offer an invaluable and powerful resource for the analysis of complex genetic traits in mice.

Multiple Mass Lesions in Pneumocystis Pneumonia.

We encountered a case of pneumocystis pneumonia (PCP) presenting with multiple mass lesions in a human immunodeficiency virus (HIV)-negative patient. Diagnosis of PCP before bronchoscopy was difficult because chest computed tomography (CT) findings were atypical of PCP and a serum (1,3)-ß-D-glucan concentration was within normal limits. Bronchoscopic biopsy and Grocott's staining enabled the diagnosis of PCP. PCP can show various patterns on chest CT images, depending on the immune status of the host. In high-risk patients, such as those who are immunocompromised, bronchoscopy should be performed with suspected cases of PCP, even if CT imaging does not show typical ground-glass opacity.