Analysis of in vivo humeral rotation of reverse total shoulder arthroplasty patients during shoulder abduction on the scapular plane with a load.

BACKGROUND: Few studies have investigated the kinematics after reverse total shoulder arthroplasty (RTSA). This study aimed to compare the shoulder kinematics in RTSA patients during shoulder abduction on the scapular plane with and without a load and yield information regarding the function of stabilizing the joints against gravity for the functional assessment of the shoulder after RTSA, which could lead to changes in postoperative rehabilitation treatment. METHODS: Twenty RTSA patients (7 men, 13 women; mean age: 78.1 [64-90] years) were examined. First, active shoulder abduction in the scapular plane was captured using single-plane fluoroscopic X-ray images. Imaging was performed by stipulating that one shoulder abduction cycle should be completed in 6 s. Two trials were conducted: one under a load equivalent to 2% of body weight and one without a load. Next, a three-dimensional (3D) model of each humeral and scapular component was matched to the silhouette of the fluoroscopic image to estimate the 3D dynamics. By using the 3D dynamic model obtained, the kinematics of the glenosphere and humeral implant were calculated relative to the shoulder abduction angle on the scapular plane and were compared between groups with and without a load. A one-way analysis of variance and a post hoc paired t-test with a statistical significance level of 0.05 were performed. RESULTS: The humeral internal rotation decreased with a load at shoulder abduction between 40° and 90° on the scapular plane (P < 0.01, effect size: 0.15). No significant differences in scapular upward rotation (P = 0.57, effect size: 0.022), external rotation (P = 0.83, effect size: 0.0083) and posterior tilting (P = 0.74, effect size: 0.013) were observed between groups with and without a load. The main effect was not observed with and without a load (P = 0.86, effect size: 0.0072). However, the scapulohumeral rhythm was significantly greater without a load during shoulder joint abduction between 40° and 60° on the scapular plane. CONCLUSION: In RTSA patients, the glenohumeral joint was less internally rotated, and the scapulohumeral rhythm decreased under loaded conditions. It was stabilized against the load through the mechanical advantage of the deltoid muscle and other muscles.

E-cadherin-dependent coordinated epithelial rotation on a two-dimensional discoidal pattern.

In vivo, cells collectively migrate in a variety of developmental and pathological contexts. Coordinated epithelial rotation represents a unique type of collective cell migrations, which has been modeled in vitro under spatially confined conditions. Although it is known that the coordinated rotation depends on intercellular interactions, the contribution of E-cadherin, a major cell-cell adhesion molecule, has not been directly addressed on two-dimensional (2D) confined substrates. Here, using well-controlled fibronectin-coated surfaces, we tracked and compared the migratory behaviors of MDCK cells expressing or lacking E-cadherin. We observed that wild-type MDCK II cells exhibited persistent and coordinated rotations on discoidal patterns, while E-cadherin knockout cells migrated in a less coordinated manner without large-scale rotation. Our comparison of the collective dynamics between these two cell types revealed a series of changes in migratory behavior caused by the loss of E-cadherin, including a decreased global migration speed, less regularity in quantified coordination, and increased average density of topological defects. Taken together, these data demonstrate that spontaneous initiation of collective epithelial rotations depends on E-cadherin under 2D discoidal confinements.

Machine learning extracts oncogenic-specific γ-H2AX foci formation pattern upon genotoxic stress.

H2AX is a histone H2A variant that becomes phosphorylated upon genotoxic stress. The phosphorylated H2AX (γ-H2AX) plays an antioncogenic role in the DNA damage response and its foci patterns are highly variable, in terms of intensities and sizes. However, whether characteristic γ-H2AX foci patterns are associated with oncogenesis (oncogenic-specific γ-H2AX foci patterns) remains unknown. We previously reported that a defect in the acetyltransferase activity of TIP60 promotes cancer cell growth in human cell lines. In this study, we compared γ-H2AX foci patterns between TIP60 wild-type cells and TIP60 HAT mutant cells by using machine learning. When focused solely on the intensity and size of γ-H2AX foci, we extracted the TIP60 HAT mutant-like oncogenic-specific γ-H2AX foci pattern among all datasets of γ-H2AX foci patterns. Furthermore, by using the dimensionality reduction method UMAP, we also observed TIP60 HAT mutant-like oncogenic-specific γ-H2AX foci patterns in TIP60 wild-type cells. In summary, we propose the existence of an oncogenic-specific γ-H2AX foci pattern and the importance of a machine learning approach to extract oncogenic signaling among the γ-H2AX foci variations.

Impact of Nuclear De Novo NAD+ Synthesis via Histone Dynamics on DNA Repair during Cellular Senescence To Prevent Tumorigenesis.

NAD+ synthesis is a fundamental process in living cells. The effects of local metabolite production on chromatin influence the epigenetic status of chromatin in DNA metabolism. We have previously shown that K5 acetylation of H2AX by TIP60 is required for the ADP ribosylation activity of PARP-1, for histone H2AX exchange at DNA damage sites. However, the detailed molecular mechanism has remained unclear. Here, we identified de novo NAD synthetase 1 (NAD syn1) as a novel binding partner to H2AX. The enzymatic activity of NAD syn1 is crucial for the ADP ribosylation activity of PARP-1 for the H2AX dynamics at sites of DNA damage. Inhibition of the NAD synthetase activity in the cell nucleus decreased the overall cellular NAD+ concentration, leading to cellular senescence. Accordingly, the acetylation-dependent H2AX dynamics and homologous recombination repair were suppressed, leading to increased tumorigenesis. Our findings have revealed the importance of de novo NAD+ production in the cell nucleus for protection against the decreased DNA repair capacity caused by cellular senescence and thus against tumorigenesis.

Epigenetic interplays between DNA demethylation and histone methylation for protecting oncogenesis.

Epigenetic systems are organized by different types of modifications on histones and DNA. To determine how epigenetic systems can produce variable, yet stable cellular outcomes, understanding the collaboration between these modifications is the key. A recent study by Yamagata and Kobayashi revealed the direct interplay between the regulation of two epigenetic modifications: DNA de-methylation by TET2 and histone H3-K36 methylation. Mechanistically, this finding could explain how cells are protected from oncogenesis by maintaining the integrity of active transcription. The recent identification of epigenetic modifier mutations in leukaemia suggested that it is not just the turning 'on' and 'off' of particular transcriptional events that causes disease occurrence, but rather it is the aberration in epigenetic regulation, i.e. the timing and duration of the activation/inactivation of these transcripts. Thus, a comprehensive understanding of how epigenetic interplays tune transcription will be the new perspective for disease research.

The Ras1-Cdc42 pathway is involved in hyphal development of Schizosaccharomyces japonicus.

Dimorphic yeasts transform into filamentous cells or hyphae in response to environmental cues. The mechanisms for the hyphal transition of dimorphic yeasts have mainly been studied in Candida albicans, an opportunistic human fungal pathogen. The Ras1-MAPK pathway is a major signal transduction pathway for hyphal transition in C. albicans. Recently, the non-pathogenic dimorphic yeast Schizosaccharomyces japonicus has also been used for genetic analyses of hyphal induction. We confirmed that Ras1-MAPK and other MAPK pathways exist in Sz. japonicus. To examine how hyphal transition is induced by environmental stress-triggered signal transduction, we studied the hyphal transition of deletion mutants of MAPK pathways in Sz. japonicus. We found that the MAPK pathways are not involved in hyphal induction, although the mating response is dependent on these pathways. However, only Ras1 deletion caused a severe defect in hyphal development via both DNA damage and environmental stressors. In fact, genes on the Cdc42 branch of the Ras1 (Ras1-Cdc42) pathway, efc25Sj, scd1Sj and scd2Sj, are required for hyphal development. Cell morphology analysis indicated that the apical growth of hyphal cells was inhibited in Ras1-Cdc42-pathway deletion mutants. Thus, the control of cell polarity by the Ras1-Cdc42 pathway is crucial for hyphal development.

The CDK-PLK1 axis targets the DNA damage checkpoint sensor protein RAD9 to promote cell proliferation and tolerance to genotoxic stress.

Genotoxic stress causes proliferating cells to activate the DNA damage checkpoint, to assist DNA damage recovery by slowing cell cycle progression. Thus, to drive proliferation, cells must tolerate DNA damage and suppress the checkpoint response. However, the mechanism underlying this negative regulation of checkpoint activation is still elusive. We show that human Cyclin-Dependent-Kinases (CDKs) target the RAD9 subunit of the 9-1-1 checkpoint clamp on Thr292, to modulate DNA damage checkpoint activation. Thr292 phosphorylation on RAD9 creates a binding site for Polo-Like-Kinase1 (PLK1), which phosphorylates RAD9 on Thr313. These CDK-PLK1-dependent phosphorylations of RAD9 suppress checkpoint activation, therefore maintaining high DNA synthesis rates during DNA replication stress. Our results suggest that CDK locally initiates a PLK1-dependent signaling response that antagonizes the ability of the DNA damage checkpoint to detect DNA damage. These findings provide a mechanism for the suppression of DNA damage checkpoint signaling, to promote cell proliferation under genotoxic stress conditions.

Mating, Spore Dissection, and Selection of Diploid Cells in Schizosaccharomyces japonicus.

Haploid yeast cells mate to form heterozygotes and subsequently undergo meiosis to form spores. This process can be used to produce gene combinations and variants that are useful for genetic analysis. For example, these spores can be used to generate double mutants or to measure genetic distances in a mutational analysis. Here, we describe mating and spore dissection procedures for Schizosaccharomyces japonicus cells. Although the overall procedures resemble those used in Schizosaccharomyces pombe, some differences exist, including the use of EMM2 medium without nitrogen (EMM-N) for mating and the shorter incubation time of 16-20 h for S. japonicus cells. Furthermore, the S. japonicus zygotes produce eight spores and thus require an "octad" analysis.

Schizosaccharomyces japonicus: A Distinct Dimorphic Yeast among the Fission Yeasts.

Genomic sequencing data and morphological properties demonstrate evolutionary relationships among groups of the fission yeast, Schizosaccharomyces Phylogenetically, S. japonicus is the furthest removed from other species of fission yeast. The basic characteristics of cell proliferation are shared among all fission yeast, including the process of binary fission during vegetative growth, conjugation and karyogamy with horsetail movement, mating-type switching, and sporulation. However, S. japonicus also exhibits characteristics that are unique to filamentous fungi. S. japonicus is a nonpathogenic yeast that exhibits dimorphism. Depending on the environmental conditions, S. japonicus transforms from yeast cells into filamentous cells (hyphae), and blue light triggers synchronous septation of hyphal cells. A rough version of the whole-genome sequence is now available, facilitating genetic manipulation of S. japonicus. Furthermore, the extensive genetic knowledge available for S. pombe is aiding the development of genetic tools for analyzing S. japonicus. S. japonicus will help shed light on the evolutionary relationships among the fission yeast.

Coordinated Regulation of TIP60 and Poly(ADP-Ribose) Polymerase 1 in Damaged-Chromatin Dynamics.

The dynamic exchange of histones alleviates the nucleosome barrier and simultaneously facilitates various aspects of cellular DNA metabolism, such as DNA repair and transcription. In response to DNA damage, the acetylation of Lys5 in the histone variant H2AX, catalyzed by TIP60, plays a key role in promoting histone exchange; however, the detailed molecular mechanism still is unclear. Here, we show that the TIP60 complex includes poly(ADP-ribose) polymerase 1 (PARP-1). PARP-1 is required for the rapid exchange of H2AX on chromatin at DNA damage sites. It is known that PARP-1 binds dynamically to damaged chromatin and is crucial for the subsequent recruitment of other repair factors, and its auto-poly(ADP-ribosyl)ation is required for the dynamics. We also show that the acetylation of histone H2AX at Lys5 by TIP60, but not the phosphorylation of H2AX, is required for the ADP-ribosylation activity of PARP-1 and its dynamic binding to damaged chromatin. Our results indicate the reciprocal regulation of K5 acetylation of H2AX and PARP-1, which could modulate the chromatin structure to facilitate DNA metabolism at damage sites. This could explain the rather undefined roles of PARP-1 in various DNA damage responses.

Eribulin upregulates miR-195 expression and downregulates Wnt3a expression in non-basal-like type of triple-negative breast cancer cell MDA-MB-231.

Triple-negative breast cancer (TNBC), which does not show hormone sensitivity, is a poor prognosis disease without an established targeted treatment, so that establishing a therapeutic target for each subtype is desired. In addition, microRNA (miRNA), a non-cording RNA 19-25 nucleotide-longs in length, is known to be involved in regulating gene expression. We examined miRNA expression after exposure to eribulin, MDA-MB-231 cells, non-basal-like type of TNBC cell lines, and HCC1143 cells, basal-like type of TNBC cell lines. The activity of caspase-3 significantly increased compared to the control in MDA-MB-231, whereas no significant difference was observed in HCC1143. The expression level of 20-miRNAs significantly increased compared to the control in MDA-MB-231 after exposure to eribulin. The expression level of 6-miRNAs also significantly increased compared to the control in HCC1143. In these 2 cell types, miR-125b-1 and miR-195 were commonly expressed. While the expression level of miR-125b-1 decreased in both cells, the expression level of miR-195 increased in MDA-MB-231 and decreased in HCC1143. The expression level of miR-195 targeting Wnt3a significantly decreased compared to the control in MDA-MB-231, whereas it significantly increased in HCC1143. These results showed that exposure to eribulin highly increased the expression of miR-195 while it decreased the expression of Wnt3a in non-basal-like type of TNBC. Some miRNAs are known to regulate other signaling pathways involved in human pathogenesis by regulating the Wnt signaling pathway, and miRNA can act as a tumor-suppressing gene; therefore, miR-195 may serve as a therapeutic target in non-basal-like type of TNBC.

Acetylation of Histone H2AX at Lys 5 by the TIP60 Histone Acetyltransferase Complex Is Essential for the Dynamic Binding of NBS1 to Damaged Chromatin.

The association and dissociation of DNA damage response (DDR) factors with damaged chromatin occurs dynamically, which is crucial for the activation of DDR signaling in a spatiotemporal manner. We previously showed that the TIP60 histone acetyltransferase complex acetylates histone H2AX, to facilitate H2AX exchange at sites of DNA damage. However, it remained unclear how the acetylation of histone H2AX by TIP60 is related to the DDR signaling. We found that the acetylation but not the phosphorylation of H2AX is essential for the turnover of NBS1 on damaged chromatin. The loss of H2AX acetylation at Lys 5 by TIP60 in cells disturbed the accumulation of NBS1 at sites of DNA damage. Although the phosphorylation of H2AX is also reportedly required for the retention of NBS1 at damage sites, our data indicated that the acetylation-dependent NBS1 turnover by TIP60 on damaged chromatin restricts the dispersal of NBS1 foci from the sites of DNA damage. These findings indicate the importance of the acetylation-dependent dynamic binding of NBS1 to damaged chromatin, created by histone H2AX exchange, for the proper accumulation of NBS1 at DNA damage sites.

Absolute quantification of acetylation and phosphorylation of the histone variant H2AX upon ionizing radiation reveals distinct cellular responses in two cancer cell lines.

Histone modifications change upon the cellular response to ionizing radiation, and their cellular amounts could reflect the DNA damage response activity. We previously reported a sensitive and reliable method for the absolute quantification of γH2AX within cells, using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The technique has broad adaptability to a variety of biological systems and can quantitate different modifications of histones. In this study, we applied it to quantitate the levels of γH2AX and K5-acetylated H2AX, and to compare the radiation responses between two cancer cell lines: HeLa and U-2 OS. The two cell lines have distinct properties in terms of their H2AX modifications. HeLa cells have relatively high γH2AX (3.1 %) against the total H2AX even in un-irradiated cells, while U-2 OS cells have an essentially undetectable level (nearly 0 %) of γH2AX. In contrast, the amounts of acetylated histones are lower in HeLa cells (9.3 %) and higher in U-2 OS cells (24.2 %) under un-irradiated conditions. Furthermore, after ionizing radiation exposure, the time-dependent increases and decreases in the amounts of histone modifications differed between the two cell lines, especially at the early time points. These results suggest that each biological system has distinct kinase/phosphatase and/or acetylase/deacetylase activities. In conclusion, for the first time, we have succeeded in simultaneously monitoring the absolute amounts of phosphorylated and acetylated cellular H2AX after ionizing radiation exposure. This multi-criteria assessment enables precise comparisons of the effects of radiation between any biological systems.

Synchronous activation of cell division by light or temperature stimuli in the dimorphic yeast Schizosaccharomyces japonicus.

Many fungi respond to light and regulate fungal development and behavior. A blue light-activated complex has been identified in Neurospora crassa as the product of the wc-1 and wc-2 genes. Orthologs of WC-1 and WC-2 have hitherto been found only in filamentous fungi and not in yeast, with the exception of the basidiomycete pathogenic yeast Cryptococcus. Here, we report that the fission yeast Schizosaccharomyces japonicus responds to blue light depending on Wcs1 and Wcs2, orthologs of components of the WC complex. Surprisingly, those of ascomycete S. japonicus are more closely related to those of the basidiomycete. S. japonicus reversibly changes from yeast to hyphae in response to environmental stresses. After incubation at 30°C, a colony of yeast was formed, and then hyphal cells extended from the periphery of the colony. When light cycles were applied, distinct dark- and bright-colored hyphal cell stripes were formed because the growing hyphal cells had synchronously activated cytokinesis. In addition, temperature cycles of 30°C for 12 h and 35°C for 12 h or of 25°C for 12 h and 30°C for 12 h during incubation in the dark induced a response in the hyphal cells similar to that of light. The stripe formation of the temperature cycles was independent of the wcs genes. Both light and temperature, which are daily external cues, have the same effect on growing hyphal cells. A dual sensing mechanism of external cues allows organisms to adapt to daily changes of environmental alteration.

Ethanol-induced apoptosis in human liver adenocarcinoma cells (SK-Hep1): Fas- and mitochondria-mediated pathways and interaction with MAPK signaling system.

For studying molecular mechanisms regulating the fate of ethanol-treated hepatocytes, involvement of Fas in ethanol-induced apoptosis was examined in human liver adenocarcinoma (SK-Hep1) cells in which the function of Fas-associated death domain (FADD) protein was knocked down by transfection. In FADD-knocked down cells, while ethanol-induced increase in generation of reactive oxygen species (ROS) was unaffected, apoptosis was significantly suppressed, demonstrating the involvement of Fas in ethanol-induced hepatocyte apoptosis more directly than in the past reports. On the other hand, effects of mitogen-activated protein kinase (MAPK), which is well known to determine the fate of various cells, on ethanol-induced apoptosis have not been examined in SK-Hep1 cells. Of three major MAPKs, only p38 MAPK and JNK were found activated by 200 mM ethanol treatment. When cells were incubated with inhibitors of p38 MAPK and JNK, ethanol-induced apoptosis was decreased while ROS generation was unaffected, and examination of pro-apoptotic Bax and anti-apoptotic Bcl-2 levels showed decrease of the former and increase of the latter. We concluded that oxidative stress inflicted by ROS triggered Fas-mediated and mitochondria-mediated apoptotic pathways in ethanol-treated SK-Hep1 cells, and that p38 MAPK and JNK were promoting mitochondrial pathway, suggesting interaction between apoptosis and MAPK signaling systems.

Hyphal differentiation induced via a DNA damage checkpoint-dependent pathway engaged in crosstalk with nutrient stress signaling in Schizosaccharomyces japonicus.

DNA damage response includes DNA repair, nucleotide metabolism and even a control of cell fates including differentiation, cell death pathway or some combination of these. The responses to DNA damage differ from species to species. Here we aim to delineate the checkpoint pathway in the dimorphic fission yeast Schizosaccharomyces japonicus, where DNA damage can trigger a differentiation pathway that is a switch from a bidirectional yeast growth mode to an apical hyphal growth mode, and the switching is regulated via a checkpoint kinase, Chk1. This Chk1-dependent switch to hyphal growth is activated with even low doses of agents that damage DNA; therefore, we reasoned that this switch may depend on other genes orthologous to the components of the classical Sz. pombe Chk1-dependent DNA checkpoint pathway. As an initial test of this hypothesis, we assessed the effects of mutations in Sz. japonicus orthologs of Sz. pombe checkpoint genes on this switch from bidirectional to hyphal growth. The same set of DNA checkpoint genes was confirmed in Sz. japonicus. We tested the effect of each DNA checkpoint mutants on hyphal differentiation by DNA damage. We found that the Sz. japonicus hyphal differentiation pathway was dependent on Sz. japonicus orthologs of Sz. pombe checkpoint genes-(SP)rad3, (SP)rad26, (SP)rad9, (SP)rad1, (SP)rad24, (SP)rad25, (SP)crb2, and (SP)chk1-that function in the DNA damage checkpoint pathway, but was not dependent on orthologs of two Sz. pombe genes-(SP)cds1 or (SP)mrc1-that function in the DNA replication checkpoint pathway. These findings indicated that although the role of each component of the DNA damage checkpoint and DNA replication checkpoint is mostly same between the two fission yeasts, the DNA damage checkpoint was the only pathway that governed DNA damage-dependent hyphal growth. We also examined whether DNA damage checkpoint signaling engaged in functional crosstalk with other hyphal differentiation pathways because hyphal differentiation can also be triggered by nutritional stress. Here, we discovered genetic interactions that indicated that the cAMP pathway engaged in crosstalk with Chk1-dependent signaling.

Construction of an insertion marker collection of Sz. japonicus (IMACS) for genetic mapping and a fosmid library covering its genome.

Measuring relative genetic distances is one of the best ways to locate genetic loci. Here we report the construction of a strains set for genetic mapping in Schizosaccharomyces japonicus, which belongs to the genus Schizosaccharomyces together with the well-studied fission yeast Sz. pombe. We constructed 29 strains that bear a positive-negative selection marker at different loci. The marker was inserted every 500 kb in the genome of Sz. japonicus. Each marker thus becomes a 'scale mark' of a chromosome that behaves like a yardstick. By determining the genetic distances from the inserted markers, the relative location of a genomic mutation can be determined. We also constructed a fosmid library that covers an entire genome of Sz. japonicus. These tools together would facilitate identification and cloning of the gene.

Construction of diploid zygotes by interallelic complementation of ade6 in Schizosaccharomyces japonicus.

The construction of diploid cells eases genetic analysis in haploid genetic systems because diploid cells allow for the characterization of essential genes. Here, we report the construction of diploid cells using ade6 point mutants that suppress each other via interallelic complementation in the fission yeast Schizosaccharomyces japonicus var japonicus (Sz. japonicus). We constructed an ade6-domK mutant in addition to the previously described ade6-domE. Phenotypes of both mutants exhibited adenine auxotrophy and red colonies. The mutations complemented the phenotypes in a mutually dependent manner. Diploid zygotes, in which the two mutations were introduced simultaneously into the same cells, were isolated by selecting for adenine independence. Such diploid cells are apparently larger in size than haploid cells, yet have a similar nuclear/cytoplasmic ratio, and thus the nuclear size control that has been reported in Sz. pombe is also present in Sz. japonicus.

Breakage of the nuclear envelope by an extending mitotic nucleus occurs during anaphase in Schizosaccharomyces japonicus.

During open mitosis in higher eukaryotic cells, the nuclear envelope completely breaks down and then mitotic chromosomes are exposed in the cytoplasm. By contrast, mitosis in lower eukaryotes, including fungi, proceeds with the nucleus enclosed in an intact nuclear envelope. The mechanism of mitosis has been studied extensively in yeast, a closed mitosis organism. Here, we describe a form of mitosis in which the nuclear envelope is torn by elongation of the nucleus in the fission yeast Schizosaccharomyces japonicus. The mitotic nucleus of Sz. japonicus adopted a fusiform shape in anaphase, and its following extension caused separation. Finally, a tear in the nuclear envelope occurred in late anaphase. At the same time, a polarized-biased localization of nuclear pores was seen in the fusiform-shaped nuclear envelope, suggesting a compromise in the mechanical integrity of the lipid membrane. It has been known that nuclear membrane remains intact in some metazoan mitosis. We found that a similar tear of the nuclear envelope was also observed in late mitosis of the Caenorhabditis elegans embryo. These findings provide insight into the diversity of mitosis and the biological significance of breakdown of the nuclear envelope.