Calcium-binding protein 7 expressed in muscle negatively regulates age-related degeneration of neuromuscular junctions in mice

The neuromuscular junction (NMJ) forms centrally in myotubes and, as the only synapse between motor neuron and myotube, are indispensable for motor activity. The midmuscle formation of NMJs, including midmuscle-restricted expression of NMJ-related genes, is governed by the muscle-specific kinase (MuSK). However, mechanisms underlying MuSK-mediated signaling are unclear. Here, we find that the Calcium-binding protein 7 (Cabp7) gene shows midmuscle-restricted expression, and muscle-specific depletion of Cabp7 in mice accelerated age-related NMJ degeneration, muscle weakness/atrophy, and motor dysfunction. Surprisingly, forced expression in muscle of CIP, an inhibitory peptide of the negative regulator of NMJ formation cyclin-dependent kinase 5 (Cdk5), restored NMJ integrity and muscle strength, and healed muscle atrophy in muscle-specific Cabp7-deficient mice, which showed increased muscle expression of the Cdk5 activator p25. These findings together demonstrate that MuSK-mediated signaling induces muscle expression of Cabp7, which suppresses age-related NMJ degeneration likely by attenuating p25 expression, providing insights into prophylactic/therapeutic intervention against age-related motor dysfunction.

Multiple ageing effects on testicular/epididymal germ cells lead to decreased male fertility in mice

In mammals, females undergo reproductive cessation with age, whereas male fertility gradually declines but persists almost throughout life. However, the detailed effects of ageing on germ cells during and after spermatogenesis, in the testis and epididymis, respectively, remain unclear. Here we comprehensively examined the in vivo male fertility and the overall organization of the testis and epididymis with age, focusing on spermatogenesis, and sperm function and fertility, in mice. We first found that in vivo male fertility decreased with age, which is independent of mating behaviors and testosterone levels. Second, overall sperm production in aged testes was decreased; about 20% of seminiferous tubules showed abnormalities such as germ cell depletion, sperm release failure, and perturbed germ cell associations, and the remaining 80% of tubules contained lower number of germ cells because of decreased proliferation of spermatogonia. Further, the spermatozoa in aged epididymides exhibited decreased total cell numbers, abnormal morphology/structure, decreased motility, and DNA damage, resulting in low fertilizing and developmental rates. We conclude that these multiple ageing effects on germ cells lead to decreased in vivo male fertility. Our present findings are useful to better understand the basic mechanism behind the ageing effect on male fertility in mammals including humans.

Age-related decline in spermatogenic activity accompanied with endothelial cell senescence in male mice

Male fertility decreases with aging, with spermatogenic decline being one of its causes. Altered testis environment is suggested as a cause of the phenotype; however, the associated mechanisms remain unclear. Herein, we investigated the age-related changes in testicular somatic cells on spermatogenic activity. The number and proliferation of spermatogonia significantly reduced with aging in mice. Interestingly, senescence-associated β-galactosidase-positive cells appeared in testicular endothelial cell (EC) populations, but not in germ cell populations, with aging. Transcriptome analysis of ECs indicated that senescence occurred in the ECs of aged mice. Furthermore, the support capacity of ECs for spermatogonial proliferation significantly decreased with aging; however, the senolytic-induced removal of senescent cells from aged ECs restored their supporting capacity to a comparable level as that of young ECs. Our results suggest that the accumulation of senescent ECs in the testis is a potential factor contributing to the age-related decline in spermatogenic activity.

TLR7/8 stress response drives histiocytosis in SLC29A3 disorders

Loss-of-function mutations in the lysosomal nucleoside transporter SLC29A3 cause lysosomal nucleoside storage and histiocytosis: phagocyte accumulation in multiple organs. However, little is known about the mechanism by which lysosomal nucleoside storage drives histiocytosis. Herein, histiocytosis in Slc29a3-/- mice was shown to depend on Toll-like receptor 7 (TLR7), which senses a combination of nucleosides and oligoribonucleotides (ORNs). TLR7 increased phagocyte numbers by driving the proliferation of Ly6Chi immature monocytes and their maturation into Ly6Clow phagocytes in Slc29a3-/- mice. Downstream of TLR7, FcRγ and DAP10 were required for monocyte proliferation. Histiocytosis is accompanied by inflammation in SLC29A3 disorders. However, TLR7 in nucleoside-laden splenic monocytes failed to activate inflammatory responses. Enhanced production of proinflammatory cytokines was observed only after stimulation with ssRNAs, which would increase lysosomal ORNs. Patient-derived monocytes harboring the G208R SLC29A3 mutation showed enhanced survival and proliferation in a TLR8-antagonist-sensitive manner. These results demonstrated that TLR7/8 responses to lysosomal nucleoside stress drive SLC29A3 disorders.

Long-term outcomes of indocyanine green fluorescence imaging-guided laparoscopic lateral pelvic lymph node dissection for clinical stage II/III middle-lower rectal cancer: a propensity score-matched cohort study

BACKGROUND

We previously reported that indocyanine green fluorescence imaging (ICG-FI)-guided laparoscopic lateral pelvic lymph node dissection (LPLND) was able to increase the total number of harvested lateral pelvic lymph nodes without impairing functional preservation. However, the long-term outcomes of ICG-FI-guided laparoscopic LPLND have not been evaluated. The aim of the present study was to compare the long-term outcomes of ICG-FI-guided laparoscopic LPLND to conventional laparoscopic LPLND without ICG-FI.

METHODS

This was a retrospective, multi-institutional study with propensity score matching. The study population included consecutive patients with middle-low rectal cancer (clinical stage II to III) who underwent laparoscopic LPLND between January 2013 and February 2018. The main evaluation items in this study were the 3-year overall survival, relapse-free survival (RFS), local recurrence rate, and lateral local recurrence (LLR) rate.

RESULTS

A total of 172 patients with middle-lower rectal cancer who had undergone laparoscopic LPLND were included in this study. After propensity score matching, 58 patients were matched in each of the ICG-FI and non-ICG-FI groups. There were no substantial differences in the baseline characteristics between the two groups. The ICG-FI group and non-ICG-FI group included 40 and 38 women and had a median age of 65 (IQR 60-72) and 66 (IQR 60-73) years, respectively. The median follow-up for all patients was 63.7 (IQR 51.3-76.8) months. The estimated respective 3-year overall survival, RFS, and local recurrence rates were 93.1%, 70.7%, and 5.2% in the ICG-FI group and 85.9%, 71.7%, and 12.8% in the non-ICG-FI group (p = 0.201, 0.653, 0.391). The 3-year cumulative LLR rate was 0% in the ICG-FI group and 9.3% in the non-ICG-FI group (p = 0.048).

CONCLUSIONS

This study revealed that laparoscopic LPLND combined with ICG-FI was able to decrease the LLR rate. It appears that ICG-FI could contribute to improving the quality of laparoscopic LPLND and strengthening local control of the lateral pelvis.

TRIALS REGISTRATION

This study was registered with the Japanese Clinical Trials Registry as UMIN000041372 ( http://www.umin.ac.jp/ctr/index.htm ).

LONRF2 is a protein quality control ubiquitin ligase whose deficiency causes late-onset neurological deficits

Protein misfolding is a major factor of neurodegenerative diseases. Post-mitotic neurons are highly susceptible to protein aggregates that are not diluted by mitosis. Therefore, post-mitotic cells may have a specific protein quality control system. Here, we show that LONRF2 is a bona fide protein quality control ubiquitin ligase induced in post-mitotic senescent cells. Under unperturbed conditions, LONRF2 is predominantly expressed in neurons. LONRF2 binds and ubiquitylates abnormally structured TDP-43 and hnRNP M1 and artificially misfolded proteins. Lonrf2-/- mice exhibit age-dependent TDP-43-mediated motor neuron (MN) degeneration and cerebellar ataxia. Mouse induced pluripotent stem cell-derived MNs lacking LONRF2 showed reduced survival, shortening of neurites and accumulation of pTDP-43 and G3BP1 after long-term culture. The shortening of neurites in MNs from patients with amyotrophic lateral sclerosis is rescued by ectopic expression of LONRF2. Our findings reveal that LONRF2 is a protein quality control ligase whose loss may contribute to MN degeneration and motor deficits.

Initial experience with the transanal approach for lateral pelvic lymph node dissection in rectal cancer

BACKGROUND

The efficacy and safety of transanal lateral pelvic lymph node dissection (TaLPLND) in rectal cancer has not yet been clarified. The aim of the present study was to evaluate the short-term results as an initial experience of TaLPLND.

METHODS

This retrospective study included patients with middle to lower rectal cancer who underwent TaLPLND from July 2018 to July 2021. Our institutions targeted lymph nodes in the internal iliac area and the obturator area for lateral pelvic lymph node dissection (LPLND).

RESULTS

A total of 30 consecutive patients with rectal cancer were included in this analysis. The median age was 60 years (range, 36-83 years), and the male-female ratio was 2:1. The median operative time was 362 min (IQR, 283-661 min), and the median intraoperative blood loss was 74 ml (IQR, 5-500 ml). Intraoperative blood transfusion was required in one case. No cases required conversion to laparotomy. TaLPLND was performed bilaterally in 13 patients (43.3%). Five patients (16.7%) underwent LPLND with combined resection of the internal iliac vessels. The median distance of the distal margin from the anal verge was 20 mm. The pathological radial margin (pRM) was positive in one case, and the negative pRM rate was 96.7%. Short-term postoperative complications (Clavien-Dindo classification grade ≥ II) were observed in nine cases (30.0%). There were no cases of reoperation or mortality. The median number of harvested lateral pelvic lymph nodes was 11 (range, 3-28). On pathological examination, lateral pelvic lymph nodes were positive for metastasis in seven cases (23.3%).

CONCLUSIONS

TaLPLND appeared to be beneficial from an oncological point of view because it was close to the upstream lymphatic drainage from the tumor. The short-term outcomes of this initial experience indicate that this novel approach is feasible.

The histone H3K36 demethylase Fbxl11 plays pivotal roles in the development of retinal late-born cell types

Histone methylation plays a vital role in retinal development. However, the role of histone H3K36 methylation in retinal development is not clear. We examined the role of H3K36 methylation by loss-of-function analysis of H3K36me1/2 demethylases, Fbxl10, and Fbxl11. We analyzed the effect of knockout of these genes in the developing and mature retina on retinal development. Knockout of Fbxl10 specifically in the developing retina did not result in gross developmental abnormalities. Although adult rod photoreceptor-specific knockout of Fbxl11 in mature retinas did not result in morphological abnormalities, Fbxl11 knockout in developing retinas increased apoptosis, suppressed the proliferation of retinal progenitor cells, and resulted in microphthalmia. Morphological analysis revealed perturbed differentiation of rod photoreceptor and bipolar cells. RNA-seq of retinas at P7 showed markedly decreased expression of genes characterizing rod photoreceptor and bipolar cells in Fbxl11-knockout retinas. In addition, perturbation of alternative splicing increased intron retention in Fbxl11-knockout retinas. Genome-wide evaluation of the H3K36 methylation status revealed that Fbxl11 knockout altered the distribution of H3K36me2/3 in genes important for rod photoreceptor development. Taken together, we show that Fbxl11 plays pivotal roles in the development of retinal late-born cell types and may contribute to tight control of H3K36 methylation during retinal development.

Gene Targeting in Mouse Embryonic Stem Cells via CRISPR/Cas9 Ribonucleoprotein (RNP)-Mediated Genome Editing

The CRISPR/Cas9-mediated genome-editing system enables the development of gene-modified mice using fertilized eggs. However, while the efficiency in developing gene knockout mice by inducing small indel mutations would be good enough, the successful ratio to create large side DNA knock-in (KI) by embryonic genome editing is still low. In contrast to the direct embryo KI method, gene targeting using embryonic stem cells (ESC) followed by chimeric mouse development by blastocyst injection still has several advantages, e.g., high-throughput in vitro targeting/screening or large-size DNA KI such as Cre, CreERT, TetON, and reporter fluorescent protein, or their fusion proteins can be carried out without serving animal lives. The ESC targeting can also be applied to strains such as BALB/c, of which embryos are known to be difficult to handle in vitro. This text describes the optimized method for either short- or large-size DNA KI in ESC by applying CRISPR/Cas9-mediated genome editing followed by chimera mice production to develop gene-manipulated mouse models.

Efficient simultaneous double DNA knock-in in murine embryonic stem cells by CRISPR/Cas9 ribonucleoprotein-mediated circular plasmid targeting for generating gene-manipulated mice

Gene targeting of embryonic stem (ES) cells followed by chimera production has been conventionally used for developing gene-manipulated mice. Although direct knock-in (KI) using murine zygote via CRISPR/Cas9-mediated genome editing has been reported, ES cell targeting still has merits, e.g., high throughput work can be performed in vitro. In this study, we first compared the KI efficiency of mouse ES cells with CRISPR/Cas9 expression vector and ribonucleoprotein (RNP), and confirmed that KI efficiency was significantly increased by using RNP. Using CRISPR/Cas9 RNP and circular plasmid with homologous arms as a targeting vector, knock-in within ES cell clones could be obtained efficiently without drug selection, thus potentially shortening the vector construction or cell culture period. Moreover, by incorporating a drug-resistant cassette into the targeting vectors, double DNA KI can be simultaneously achieved at high efficiency by a single electroporation. This technique will help to facilitate the production of genetically modified mouse models that are fundamental for exploring topics related to human and mammalian biology.

Genetic loss of function of Ptbp1 does not induce glia-to-neuron conversion in retina

Direct reprogramming of glia into neurons is a potentially promising approach for the replacement of neurons lost to injury or neurodegenerative disorders. Knockdown of the polypyrimidine tract-binding protein Ptbp1 has been recently reported to induce efficient conversion of retinal Mϋller glia into functional neurons. Here, we use a combination of genetic lineage tracing, single-cell RNA sequencing (scRNA-seq), and electroretinogram analysis to show that selective induction of either heterozygous or homozygous loss-of-function mutants of Ptbp1 in adult retinal Mϋller glia does not lead to any detectable level of neuronal conversion. Only a few changes in gene expression are observed in Mϋller glia following Ptbp1 deletion, and glial identity is maintained. These findings highlight the importance of using genetic manipulation and lineage-tracing methods in studying cell-type conversion.

Abstract 516: Splice Factor Polypyrimidine Tract-binding Protein 1 (PTBP1) Primes Endothelial Inflammation In Atherogenic Disturbed Flow Conditions

NFκB mediated endothelial activation drives leukocyte recruitment and atherosclerosis, in part through upregulation of adhesion molecules Icam1 and Vcam. The endothelium is primed for cytokine activation of NFκB by exposure to low and disturbed blood flow (LDF). While priming leads to an exaggerated expression of Icam1 and Vcam following cytokine stimulation, the molecular underpinnings are not understood. In a model of LDF, platelets were required for the increased expression of several RNA-binding splice factors, including Polypyrimidine tract binding protein (Ptbp1). This was coordinated with changes in RNA splicing in the NFκB pathway in primed cells, leading us to examine splice factors as mediators of priming. Using Icam1 and Vcam induction by TNFα stimulation as a readout, we performed a CRISPR-Cas9 screen of these factors and identified a requirement for Ptbp1 in priming. Deletion of Ptbp1 had no obvious effect on cell proliferation or viability, but reversed LDF splicing patterns and inhibited NFκB nuclear translocation and transcriptional activation of nearly all downstream targets, including Icam1 and Vcam. In human coronary arteries, elevated PTBP1 correlates with expression of TNF pathway genes and plaque. In vivo , endothelial specific deletion of Ptbp1 reduced Icam1 expression and myeloid cell infiltration at regions of LDF in atherosclerotic mice and limited atherosclerosis. Together, our data show that Ptbp1, which is induced in a subset of the endothelium by innate immune cell recruitment at regions of LDF, is required for priming of the endothelium for subsequent NFκB activation, myeloid cell recruitment and atherosclerosis.

Handlebody decompositions of three-manifolds and polycontinuous patterns

We introduce the concept of a handlebody decomposition of a three-manifold, a generalization of a Heegaard splitting, or a trisection. We show that two handlebody decompositions of a closed orientable three-manifold are stably equivalent. As an application to materials science, we consider a mathematical model of polycontinuous patterns and discuss a topological study of microphase separation of a block copolymer melt.

MYCL-mediated reprogramming expands pancreatic insulin-producing cells

β cells have a limited capacity for regeneration, which predisposes towards diabetes. Here, we show that, of the MYC family members, Mycl plays a key role in proliferation of pancreatic endocrine cells. Genetic ablation of Mycl causes a reduction in the proliferation of pancreatic endocrine cells in neonatal mice. By contrast, the expression of Mycl in adult mice stimulates the proliferation of β and α cells, and the cells persist after withdrawal of Mycl expression. A subset of the expanded α cells give rise to insulin-producing cells after this withdrawal. Transient Mycl expression in vivo is sufficient to normalize the hyperglycaemia of diabetic mice. In vitro expression of Mycl similarly provokes active replication in islet cells, even in those from aged mice. Finally, we show that MYCL stimulates the division of human adult cadaveric islet cells. Our results demonstrate that the induction of Mycl alone expands the functional β-cell population, which may provide a regenerative strategy for β cells.

DMRT1-mediated reprogramming drives development of cancer resembling human germ cell tumors with features of totipotency

In vivo reprogramming provokes a wide range of cell fate conversion. Here, we discover that in vivo induction of higher levels of OSKM in mouse somatic cells leads to increased expression of primordial germ cell (PGC)-related genes and provokes genome-wide erasure of genomic imprinting, which takes place exclusively in PGCs. Moreover, the in vivo OSKM reprogramming results in development of cancer that resembles human germ cell tumors. Like a subgroup of germ cell tumors, propagated tumor cells can differentiate into trophoblasts. Moreover, these tumor cells give rise to induced pluripotent stem cells (iPSCs) with expanded differentiation potential into trophoblasts. Remarkably, the tumor-derived iPSCs are able to contribute to non-neoplastic somatic cells in adult mice. Mechanistically, DMRT1, which is expressed in PGCs, drives the reprogramming and propagation of the tumor cells in vivo. Furthermore, the DMRT1-related epigenetic landscape is associated with trophoblast competence of the reprogrammed cells and provides a therapeutic target for germ cell tumors. These results reveal an unappreciated route for somatic cell reprogramming and underscore the impact of reprogramming in development of germ cell tumors.

Rubicon prevents autophagic degradation of GATA4 to promote Sertoli cell function

Autophagy degrades unnecessary proteins or damaged organelles to maintain cellular function. Therefore, autophagy has a preventive role against various diseases including hepatic disorders, neurodegenerative diseases, and cancer. Although autophagy in germ cells or Sertoli cells is known to be required for spermatogenesis and male fertility, it remains poorly understood how autophagy participates in spermatogenesis. We found that systemic knockout mice of Rubicon, a negative regulator of autophagy, exhibited a substantial reduction in testicular weight, spermatogenesis, and male fertility, associated with upregulation of autophagy. Rubicon-null mice also had lower levels of mRNAs of Sertoli cell–related genes in testis. Importantly, Rubicon knockout in Sertoli cells, but not in germ cells, caused a defect in spermatogenesis and germline stem cell maintenance in mice, indicating a critical role of Rubicon in Sertoli cells. In mechanistic terms, genetic loss of Rubicon promoted autophagic degradation of GATA4, a transcription factor that is essential for Sertoli cell function. Furthermore, androgen antagonists caused a significant decrease in the levels of Rubicon and GATA4 in testis, accompanied by elevated autophagy. Collectively, we propose that Rubicon promotes Sertoli cell function by preventing autophagic degradation of GATA4, and that this mechanism could be regulated by androgens.

Androgens, known as “male” hormones, stimulate and activate their receptors in various tissues, including testicular cells and skeletal muscle cells, thereby maintaining spermatogenesis and muscle mass. Notably, androgens-dependent maintenance of male reproduction is of particular interest because the incidence of male infertility has increased in recent decades. Previous studies revealed that Androgen receptor knockout in Sertoli cells causes defective spermatogenesis, indicating a crucial role of androgens in Sertoli cells. Another study suggested that fatherhood-dependent downregulation of androgens could decrease male fertility, leading the male to concentrate on parenting existing offspring. However, it remains largely unknown how androgen regulates Sertoli cell function for male reproduction. In the present study, our results suggest that androgens regulate testicular levels of Rubicon, a negative regulator of autophagy, to control autophagic degradation of GATA4 that is required for Sertoli cell function. Because autophagy and androgens participate in various cellular processes, we anticipate that this study will provide a solid evidence for understanding such processes.

Skewed endosomal RNA responses from TLR7 to TLR3 in RNase T2-deficient macrophages

RNase T2, a ubiquitously expressed RNase, degrades RNAs in the endosomal compartments. RNA sensors, double-stranded RNA (dsRNA)-sensing TLR3 and single-stranded RNA (ssRNA)-sensing TLR7, are localized in the endosomal compartment in mouse macrophages. We here studied the role of RNase T2 in TLR3 and TLR7 responses in macrophages. Macrophages expressed RNase T2 and a member of the RNase A family RNase 4. RNase T2 was also expressed in plasmacytoid and conventional dendritic cells. Treatment with dsRNAs or type I interferon (IFN) upregulated expression of RNase T2 but not RNase 4. RNase T2-deficiency in macrophages upregulated TLR3 responses but impaired TLR7 responses. Mechanistically, RNase T2 degraded both ds- and ssRNAs in vitro, and its mutants showed a positive correlation between RNA degradation and the rescue of altered TLR3 and TLR7 responses. H122A and C188R RNase T2 mutations, not H69A and E118V mutations, impaired both RNA degradation and the rescue of altered TLR3 and TLR7 responses. RNase T2 in bone marrow-derived macrophages was broadly distributed from early endosomes to lysosomes, and colocalized with the internalized TLR3 ligand poly(I:C). These results suggest that RNase T2-dependent RNA degradation in endosomes/lysosomes negatively and positively regulates TLR3 and TLR7 responses, respectively, in macrophages.

RNA-binding protein Ptbp1 regulates alternative splicing and transcriptome in spermatogonia and maintains spermatogenesis in concert with Nanos3

PTBP1, a well-conserved RNA-binding protein, regulates cellular development by tuning posttranscriptional mRNA modification such as alternative splicing (AS) or mRNA stabilization. We previously revealed that the loss of Ptbp1 in spermatogonia causes the dysregulation of spermatogenesis, but the molecular mechanisms by which PTBP1 regulates spermatogonium homeostasis are unclear. In this study, changes of AS or transcriptome in Ptbp1-knockout (KO) germline stem cells (GSC), an in vitro model of proliferating spermatogonia, was determined by next generation sequencing. We identified more than 200 differentially expressed genes, as well as 85 genes with altered AS due to the loss of PTBP1. Surprisingly, no differentially expressed genes overlapped with different AS genes in Ptbp1-KO GSC. In addition, we observed that the mRNA expression of Nanos3, an essential gene for normal spermatogenesis, was significantly decreased in Ptbp1-KO spermatogonia. We also revealed that PTBP1 protein binds to Nanos3 mRNA in spermatogonia. Furthermore, Nanos3^+/−;Ptbp1^+/− mice exhibited abnormal spermatogenesis, which resembled the effects of germ cell-specific Ptbp1 KO, whereas no significant abnormality was observed in mice heterozygous for either gene alone. These data implied that PTBP1 regulates alternative splicing and transcriptome in spermatogonia under different molecular pathways, and contributes spermatogenesis, at least in part, in concert with NANOS3.

NELL2-mediated lumicrine signaling through OVCH2 is required for male fertility

The lumicrine system is a postulated signaling system in which testis-derived (upstream) secreted factors enter the male reproductive tract to regulate epididymal (downstream) pathways required for sperm maturation. Until now, no lumicrine factors have been identified. We demonstrate that a testicular germ-cell-secreted epidermal growth factor-like protein, neural epidermal growth factor-like-like 2 (NELL2), specifically binds to an orphan receptor tyrosine kinase, c-ros oncogene 1 (ROS1), and mediates the differentiation of the initial segment (IS) of the caput epididymis. Male mice in which Nell2 had been knocked out were infertile. The IS-specific secreted proteases, ovochymase 2 (OVCH2) and A disintegrin and metallopeptidase 28 (ADAM28), were expressed upon IS maturation, and OVCH2 was required for processing of the sperm surface protein ADAM3, which is required for sperm fertilizing ability. This work identifies a lumicrine system essential for testis-epididymis-spermatozoa (NELL2-ROS1-OVCH2-ADAM3) signaling and male fertility.

RNA-binding protein Ptbp1 is essential for BCR-mediated antibody production

The RNA-binding protein polypyrimidine tract-binding protein-1 (Ptbp1) binds to the pyrimidine-rich sequence of target RNA and controls gene expression via post-transcriptional regulation such as alternative splicing. Although Ptbp1 is highly expressed in B lymphocytes, its role to date is largely unknown. To clarify the role of Ptbp1 in B-cell development and function, we generated B-cell-specific Ptbp1-deficient (P1BKO) mice. B-cell development in the bone marrow, spleen and peritoneal cavity of the P1BKO mice was nearly normal. However, the P1BKO mice had significantly lower levels of natural antibodies in serum compared with those of the control mice. To investigate the effect of Ptbp1 deficiency on the immune response in vivo, we immunized the P1BKO mice with T-cell-independent type-2 (TI-2) antigen NP-Ficoll and T-cell-dependent (TD) antigen NP-CGG. We found that B-cell-specific Ptbp1 deficiency causes an immunodeficiency phenotype due to defective production of antibody against both TI-2 and TD antigen. This immunodeficiency was accompanied by impaired B-cell receptor (BCR)-mediated B-cell activation and plasmablast generation. These findings demonstrate that Ptbp1 is essential for the humoral immune response.

Trends in the serovar and antimicrobial resistance in clinical isolates of Salmonella enterica from cattle and pigs between 2002 and 2016 in Japan

AIMS

Given the significance of Salmonella enterica in both human and animal health, and a recent global dissemination of Salmonella 4,[5],12:i:-, changes in the prevalent serovars and antimicrobial resistance in clinical isolates of Salmonella from cattle and pigs were investigated in Japan.

METHODS AND RESULTS

The serovars and antimicrobial susceptibilities of 1605 Salmonella enterica isolated from cattle (n = 894) and swine (n = 711) between 2002 and 2016 were examined. The most common serovar among all samples was Salmonella Typhimurium. However, its monophasic variant with antigenic structure S. 4,[5],12:i:-, which was first detected in cattle in 2006 and swine in 2010, has been rapidly increasing in incidence and resistance. Resistance rates to cefotaxime and ciprofloxacin were generally low (<10% in the cattle isolates and <5% in the swine isolates); however, isolates resistant to more than five antimicrobials, which often include these antimicrobials, were recently detected in Salmonella Dublin, S. 4,[5],12:i:-, S. Typhimurium, Salmonella Newport, Salmonella Choleraesuis and Salmonella 6,7:c:-. Among them, two S. 4,[5],12:i:- isolates possessed extended-spectrum β-lactamase-encoding genes; bla_SHV-12 or bla_CTX-M-55 , respectively, while all the five S. Typhimurium isolates possessed AmpC-type β-lactamase gene of bla_CMY-2 .

CONCLUSIONS

S. 4,[5],12:i:- has been rapidly increasing and exhibiting a remarkable change in antimicrobial resistance in Japan. Considering certain serovars are characterized by multidrug resistance including medically important antimicrobials, continuous monitoring and appropriate measures are required to protect public health and veterinary husbandry.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study presents a trend in the serovars and antimicrobial resistance in clinical isolates of Salmonella from cattle and pigs in Japan, and showed that there were certain types of Salmonella serovars depending on the animal origin which needs more attention.

PTBP1 contributes to spermatogenesis through regulation of proliferation in spermatogonia

Polypyrimidine tract-binding protein 1 (PTBP1) is a highly conserved RNA-binding protein that is a well-known regulator of alternative splicing. Testicular tissue is one of the richest tissues with respect to the number of alternative splicing mRNA isoforms, but the molecular role(s) of PTBP1 in the regulation of these isoforms during spermatogenesis is still unclear. Here, we developed a germ cell–specific Ptbp1 conditional knockout (cKO) mouse model by using the Cre-loxP system to investigate the role of PTBP1 in spermatogenesis. Testis weight in Ptbp1 cKO mice was comparable to that in age-matched controls until 3 weeks of age; at ≥ 2 months old, testis weight was significantly lighter in cKO mice than in age-matched controls. Sperm count in Ptbp1 cKO mice at 2 months old was comparable to that in controls, whereas sperm count significantly decreased at 6 months old. Seminiferous tubules that exhibited degeneration in spermatogenic function were more evident in the 2-month-old Ptbp1 cKO mice than in controls. In addition, the early neonatal proliferation of spermatogonia, during postnatal days 1–5, was significantly retarded in Ptbp1 cKO mice compared with that in controls. An in vitro spermatogonia culture model (germline stem cells) revealed that hydroxytamoxifen-induced deletion of PTBP1 from germline stem cells caused severe proliferation arrest accompanied by an increase of apoptotic cell death. These data suggest that PTBP1 contributes to spermatogenesis through regulation of spermatogonia proliferation.

Mid-term results of alumina ceramic unlinked total elbow arthroplasty with cement fixation for patients with rheumatoid arthritis

Aims

The aim of this study was to report the mid-term clinical outcome of cemented unlinked J-alumina ceramic elbow (JACE) arthroplasties when used in patients with rheumatoid arthritis (RA).

Patients and Methods

We retrospectively reviewed 87 elbows, in 75 patients with RA, which was replaced using a cemented JACE total elbow arthroplasty (TEA) between August 2003 and December 2012, with a follow-up of 96%. There were 72 women and three men, with a mean age of 62 years (35 to 79). The mean follow-up was nine years (2 to 14). The clinical condition of each elbow before and after surgery was assessed using the Mayo Elbow Performance Index (MEPI, 0 to 100 points). Radiographic loosening was defined as a progressive radiolucent line of >1 mm that was completely circumferential around the prosthesis.

Results

The mean MEPI scores significantly improved from 40 (10 to 75) points preoperatively to 95 (30 to 100) points at final follow-up (p < 0.0001). Complications were noted in ten elbows (ten patients; 11%). Two had an intraoperative humeral fracture which was treated by fixation and united. One had a postoperative fracture of the olecranon which united with conservative treatment and one had a radial neuropathy which resolved. Further surgery was required for one with a dislocation, three with an ulnar neuropathy and one with a postoperative humeral fracture. Revision with removal of the components was performed in one elbow due to deep infection. There was no radiographic evidence of loosening around the components.With any revision surgery or revision with implant removal as the endpoint, the rates of survival up to 14 years were 93% (95% confidence interval (CI), 83.9 to 96.6) and 99% (95% CI 91.9 to 99.8), respectively, as determined by Kaplan-Meier analysis.

Conclusion

With the appropriate indications, the mid-term clinical performance of the cemented JACE TEA is reliable and comparable to other established TEAs in the management of the elbow in patients with RA.

Cite this article: Bone Joint J 2018;100-B:1066–73.

Distribution of gene segments of the pandemic A(H1N1) 2009 virus lineage in pig populations

Swine influenza viruses (SIVs) are important not only for pig farming, but also for public health. In fact, pandemic A(H1N1) 2009 viruses [A(H1N1)pdm09] were derived from SIVs. Therefore, timely characterization of locally circulating SIVs is necessary for understanding the global status of SIVs. To genetically characterize SIVs circulating in Japanese pig populations, we isolated 24 SIVs of three subtypes (17 H1N1, four H1N2 and three H3N2 strains) from 14 pig farms in Japan from 2013 to 2016. Genetic analyses revealed that the haemagglutinin (HA) and neuraminidase (NA) genes of the 17 H1N1 and the HA gene of one H1N2, A/swine/Aichi/02/2016 (H1N2), SIVs belonged to the A(H1N1)pdm09 lineage. More importantly, all of the remaining six gene segments (i.e., PB1, PB1, PA, NP, M and NS) of the 24 SIVs, regardless of the HA and NA subtype, were also classified as belonging to the A(H1N1)pdm09 lineage. These results indicate that gene segments of A(H1N1)pdm09 lineage are widely distributed in SIVs circulating in Japanese pig populations In addition, the NA gene of A/swine/Aichi/02/2016 (H1N2) shared less than 88.5% nucleotide identity with that of the closest relative A/swine/Miyagi/5/2003 (H1N2), which was isolated in Japan in 2003. These results indicate the sustained circulation of classical H1N2-derived SIVs with remarkable diversity in the NA genes in Japanese pig populations. These findings highlight the necessity of both intensive biosecurity systems and active SIV surveillance in pig populations worldwide for both animal and public health.

WNT regulation of embryonic development likely involves pathways independent of nuclear CTNNB1

The bovine was used to examine the potential for WNT signaling to affect the preimplantation embryo. Expression of seven key genes involved in canonical WNT signaling declined to a nadir at the morula or blastocyst stage. Expression of 80 genes associated with WNT signaling in the morula and inner cell mass (ICM) and trophectoderm (TE) of the blastocyst was also evaluated. Many genes associated with WNT signaling were characterized by low transcript abundance. Seven genes were different between ICM and TE, and all of them were overexpressed in TE as compared to ICM, including WNT6, FZD1, FZD7, LRP6, PORCN, APC and SFRP1 Immunoreactive CTNNB1 was localized primarily to the plasma membrane at all stages examined from the 2-cell to blastocyst stages of development. Strikingly, neither CTNNB1 nor non-phospho (i.e., active) CTNNB1 was observed in the nucleus of blastomeres at any stage of development even after the addition of WNT activators to culture. In contrast, CTNNB1 associated with the plasma membrane was increased by activators of WNT signaling. The planar cell polarity pathway (PCP) could be activated in the embryo as indicated by an experiment demonstrating an increase in phospho-JNK in the nucleus of blastocysts treated with the non-canonical WNT11. Furthermore, WNT11 improved development to the blastocyst stage. In conclusion, canonical WNT signaling is attenuated in the preimplantation bovine embryo but WNT can activate the PCP component JNK. Thus, regulation of embryonic development by WNT is likely to involve activation of pathways independent of nuclear actions of CTNNB1.

Distribution of Glycoconjugates in the Kidney Studied by Use of Labeled Lectins

Distribution of glycoconjugates in different areas of the rat kidney was studied by light and electron microscopy using six different horseradish peroxidase-labeled lectins. Glomeruli and brush borders of the proximal tubules reacted differently to these lectins, which indicated differences in the carbohydrate compositions of those regions. The ascending limb of Henle's loop (ALH) had strong binding sites for peanut agglutinin (PNA) and soybean agglutinin (SBA). Dolichos biflorus agglutinin (DBA) did not stain the cells of ALH but did stain those of distal convoluted tubules (DCT). DBA is a good marker for distinguishing ALH from DCT. DBA, PNA, and SBA were also good markers of the collecting duct. Ricinus communis agglutinin (RCA-1) and wheat germ agglutinin (WGA) diffusely stained the various components of different parts of the kidney.

Regulation of gene expression in the bovine blastocyst by colony stimulating factor 2

Background

Colony stimulating factor 2 can have multiple effects on the function of the preimplantation embryo that include increased potential to develop to the blastocyst stage, reduced apoptosis, and enhanced ability of inner cell mass (ICM) to remain pluripotent after culture. The objective of the current experiment was to identify genes regulated by CSF2 in the ICM and trophectoderm (TE) of the bovine blastocyst with the goal of identifying possible molecular pathways by which CSF2 increases developmental competence for survival. Embryos were produced in vitro and cultured from Day 6 to 8 in serum-free medium containing 10 ng/ml recombinant bovine CSF2 or vehicle. Blastocysts were harvested at Day 8 and ICM separated from TE by magnetic-activated cell sorting. RNA was purified and used to prepare amplified cDNA, which was then subjected to high-throughput sequencing using the SOLiD 4.0 system. Three pools of amplified cDNA were analyzed per treatment.

Results

The number of genes whose expression was regulated by CSF2, using P < 0.05 and >1.5-fold difference as cut-offs, was 945 in the ICM (242 upregulated by CSF2 and 703 downregulated) and 886 in the TE (401 upregulated by CSF2 and 485 downregulated). Only 49 genes were regulated in a similar manner by CSF2 in both cell types. The three significant annotation clusters in which genes regulated by ICM were overrepresented were related to membrane signaling. Genes downregulated by CSF2 in ICM were overrepresented in several pathways including those for ERK and AKT signaling. The only significant annotation cluster containing an overrepresentation of genes regulated by CSF2 in TE was for secreted or extracellular proteins. In addition, genes downregulated in TE were overrepresented in TGFβ and Nanog pathways.

Conclusions

Differentiation of the blastocyst is such that, by Day 8 after fertilization, the ICM and TE respond differently to CSF2. Analysis of the genes regulated by CSF2 in ICM and TE are suggestive that CSF2 reinforces developmental fate and function of both cell lineages.

Electronic supplementary material

The online version of this article (doi:10.1186/s13104-016-2038-y) contains supplementary material, which is available to authorized users.

The Histone Demethylase FBXL10 Regulates the Proliferation of Spermatogonia and Ensures Long-Term Sustainable Spermatogenesis in Mice

The F-box and leucine-rich repeat protein 10 (Fbxl10) gene encodes a protein that catalyzes demethylation of H3K4 and H3K36. In this study, we show the important roles of FBXL10 as a histone demethylase in sustainable sperm production using mice in which the JmjC domain of Fbxl10 was deleted (Fbxl10(DeltaJ/DeltaJ)). In histological analysis, testis sections from 10-wk-old Fbxl10(DeltaJ/DeltaJ) mice appeared normal. On the other hand, testes from 7-mo-old Fbxl10(DeltaJ/DeltaJ) mice contained a greater ratio of seminiferous tubules exhibiting degeneration of spermatogenesis. Further analysis using an in vitro spermatogonia culture system, that is, germline stem cells (GSCs), revealed that Fbxl10(DeltaJ/DeltaJ) GSCs expressed a significantly higher level of P21 and P19 mRNA, cyclin-dependent kinase inhibitors and also known as cellular senescence markers, than wild-type (WT) GSCs. Furthermore, the ratio of Fbxl10(DeltaJ/DeltaJ) GSCs in G0/G1 phase was higher and the ratios in S and G2/M phases were lower than the corresponding ratios of WT GSCs, and the doubling speed of Fbxl10(DeltaJ/DeltaJ) GSCs was significantly slower than that of WT GSCs. In addition to these in vitro results, an in vivo study indicated that recovery of spermatogenesis after a transient reduction in the number of testicular germ cells by busulfan treatment was significantly slower in Fbxl10(DeltaJ/DeltaJ) mice than in WT mice. These data suggest that Fbxl10 plays important roles in long-term sustainable spermatogenesis via regulating cell cycle.

Synthesis of highly refractive and highly fluorescent rigid cyanuryl polyimines with polycyclic aromatic hydrocarbon pendants

A series of rigid cyanuryl polyimines, polyguanamines (PGs) bearing polycyclic aromatic hydrocarbon pendants were successfully synthesized from 2-substituted 4,6-dichloro-1,3,5-triazine and aromatic diamine monomers.

The requirement for protein kinase C delta (PRKCD) during preimplantation bovine embryo development

Protein kinase C (PKC) delta (PRKCD) is a member of the novel PKC subfamily that regulates gene expression in bovine trophoblast cells. Additional functions for PRKCD in early embryonic development in cattle have not been fully explored. The objectives of this study were to describe the expression profile of PRKCD mRNA in bovine embryos and to examine its biological roles during bovine embryo development. Both PRKCD mRNA and protein are present throughout early embryo development and increases in mRNA abundance are evident at morula and blastocyst stages. Phosphorylation patterns are consistent with detection of enzymatically active PRKCD in bovine embryos. Exposure to a pharmacological inhibitor (rottlerin) during early embryonic development prevented development beyond the eight- to 16-cell stage. Treatment at or after the 16-cell stage reduced blastocyst development rates, total blastomere numbers and inner cell mass-to-trophoblast cell ratio. Exposure to the inhibitor also decreased basal interferon tau (IFNT) transcript abundance and abolished fibroblast growth factor-2 induction of IFNT expression. Furthermore, trophoblast adhesion and proliferation was compromised in hatched blastocysts. These observations provide novel insights into PRKCD mRNA expression profiles in bovine embryos and provide evidence for PRKCD-dependent regulation of embryonic development, gene expression and post-hatching events.

Genetic diversity of highly pathogenic H5N8 avian influenza viruses at a single overwintering site of migratory birds in Japan, 2014/15

We isolated eight highly pathogenic H5N8 avian influenza viruses (H5N8 HPAIVs) in the 2014/15 winter season at an overwintering site of migratory birds in Japan. Genetic analyses revealed that these isolates were divided into three groups, indicating the co-circulation of three genetic groups of H5N8 HPAIV among these migratory birds. These results also imply the possibility of global redistribution of the H5N8 HPAIVs via the migration of these birds next winter.

The histone demethylase Fbxl11/Kdm2a plays an essential role in embryonic development by repressing cell-cycle regulators

Methylation and de-methylation of histone lysine residues play pivotal roles in mammalian early development; these modifications influence chromatin architecture and regulate gene transcription. Fbxl11 (F-box and leucine-rich repeat 11)/Kdm2a is a histone demethylase that selectively removes mono- and di-methylation from histone H3K36. Previously, two other histone H3K36 demethylases (Jmjd5 or Fbxl10) were analyzed based on the phenotypes of the corresponding knockout (KO) mice; the results of those studies implicated H3K36 demethylases in cell proliferation, apoptosis, and senescence (Fukuda et al., 2011; Ishimura et al., 2012). To elucidate the physiological role of Fbxl11, we generated and examined Fbxl11 KO mice. Fbxl11 was expressed throughout the body during embryogenesis, and the Fbxl11 KO mice exhibited embryonic lethality at E10.5-12.5, accompanied with severe growth defects leading to reduced body size. Furthermore, knockout of Fbxl11 decreased cell proliferation and increased apoptosis. The lack of Fbxl11 resulted in downregulation of the Polycomb group protein (PcG) Ezh2, PcG mediated H2A ubiquitination and upregulation of the cyclin-dependent kinase inhibitor p21Cip1. Taken together, our findings suggest that Fbxl11 plays an essential role in embryonic development and homeostasis by regulating cell proliferation and survival.

Development of FGF2-dependent pluripotent stem cells showing naive state characteristics from murine preimplantation inner cell mass

Two distinct types of embryonic pluripotent stem cells can be established from either the inner cell mass (ICM) of preimplantation blastocyst (leukemia inhibitory factor (LIF)-dependent embryonic stem cell, ESC, called naive state) or the epiblast of postimplantation fetuses (fibroblast growth factor 2 (FGF2)-dependent epiblast stem cells, EpiSC, called primed state). Here, we report that naive pluripotent stem cell was established from the ICM, but maintained its self-renewal by treatment with FGF2 and mouse embryonic fibroblasts (MEFs) when they were exposed FGF2 during establishment. This cell line is competent to contribute to chimeric animals, including germ cells, at high efficiency. The ERK1/2, SMAD2/3, and JAK/STAT3 pathways are essential to maintain self-renewal. Inhibition of ERK1/2 or SMAD2/3 initiates transition to a naive state ESC-like state, whereas inhibition of JAK/STAT3 promotes a primed EpiSC-like character. Our present results could provide novel insights into understanding the growth factor environment and ICM plasticity, and mechanisms which orchestrate the pluripotency of embryonic stem cells and the capacity for chimeric contributions.

Delay in cleavage of porcine embryos after intracytoplasmic sperm injection (ICSI) shows poorer embryonic development

In pigs, the embryonic developmental ability after intracytoplasmic sperm injection (ICSI) is inferior to that resulting from in vitro fertilization (IVF). We evaluated the timing of cell division up to blastocyst formation on embryonic development after ICSI using either whole sperm (w-ICSI) or the sperm head alone (h-ICSI) and IVF as a control. At 10 h after ICSI or IVF, we selected only zygotes, and each of the zygotes/embryos was evaluated for cleavage every 24 h until 168 h. We then observed a delay in the 1st and 2nd cleavages of h-ICSI embryos and also in blastocoele formation by w-ICSI embryos in comparison with IVF embryos. The rate of blastocyst formation and the quality of blastocysts in both ICSI groups were inferior to those in the IVF group. In conclusion, the delay in cleavage of porcine ICSI embryos shows poorer embryonic development.

Regulation of pluripotency of inner cell mass and growth and differentiation of trophectoderm of the bovine embryo by colony stimulating factor 2

Colony-stimulating factor 2 (CSF2) enhances competence of the bovine embryo to establish and maintain pregnancy after the embryo is transferred into a recipient. Mechanisms involved could include regulation of lineage commitment, growth, or differentiation of the inner cell mass (ICM) and trophectoderm (TE). Experiments were conducted to evaluate regulation by CSF2 of pluripotency of the ICM and differentiation and growth of the TE. Embryos were cultured with 10 ng/ml recombinant bovine CSF2 or a vehicle control from Days 5 to 7 or 6 to 8 postinsemination. CSF2 increased the number of putative zygotes that developed to blastocysts when the percent of embryos becoming blastocysts in the control group was low but decreased blastocyst yield when blastocyst development in controls was high. ICM isolated from blastocysts by lysing the trophectoderm using antibody and complement via immunosurgery were more likely to survive passage when cultured on mitomycin C-treated fetal fibroblasts if derived from blastocysts treated with CSF2 than if from control blastocysts. There was little effect of CSF2 on characteristics of TE outgrowths from blastocysts. The exception was a decrease in outgrowth size for embryos treated with CSF2 from Days 5 to 7 and an increase in expression of CDX2 when treatment was from Days 6 to 8. Expression of the receptor subunit gene CSF2RA increased from the zygote stage to the 9-16 cell stage before decreasing to the blastocyst stage. In contrast, CSF2RB was undetectable at all stages. In conclusion, CSF2 improves competence of the ICM to survive in a pluripotent state and alters TE outgrowths. Actions of CSF2 occur through a signaling pathway that is likely to be independent of CSF2RB.

Magnesium intake decreases Type 2 diabetes risk through the improvement of insulin resistance and inflammation: the Hisayama Study

AIMS

Early studies have shown that magnesium intake decreases the risk of Type 2 diabetes, but the results are still inconsistent. We prospectively examined the association between magnesium intake and incidence of Type 2 diabetes in a general Japanese population.

METHODS

A total of 1999 subjects without diabetes aged 40-79 years who underwent a 75-g oral glucose tolerance test were followed up prospectively for a mean of 15.6 years.

RESULTS

During the follow-up, 417 subjects developed Type 2 diabetes. The age- and sex-adjusted incidence of Type 2 diabetes significantly decreased with increasing magnesium intake quartile levels (≤ 148.5, 148.6-171.5, 171.6-195.5 and ≥ 195.6 mg/day, P for trend = 0.01). In multivariate analyses, after adjusting for comprehensive risk factors and other dietary factors, the hazard ratio of Type 2 diabetes was 0.67 (95% CI 0.49-0.92; P = 0.01) in the third quartile and 0.63 (95% CI 0.44-0.90; P = 0.01) in the highest quartile compared with the first quartile. In addition, the risk of Type 2 diabetes was 14% lower (P = 0.04) for a 1-sd increment of log-transformed magnesium intake in the multivariate-adjusted model. In stratified analysis, there were statistically significant interactions between magnesium intake and levels of homeostasis model assessment of insulin resistance, high-sensitivity C-reactive protein or alcohol intake on the risk of Type 2 diabetes (all P < 0.05).

CONCLUSIONS

Our findings suggest that increased magnesium intake was a significant protective factor for the incidence of Type 2 diabetes in the general Japanese population, especially among subjects with insulin resistance, low-grade inflammation and a drinking habit.