Morc3 mutant mice exhibit reduced cortical area and thickness, accompanied by altered haematopoietic stem cells niche and bone cell differentiation

Bacterial heat shock protein: A new crosstalk between T lymphocyte and macrophage via JAK2/STAT1 pathway in bloodstream infection

Bloodstream infection (BSI) refers to the infection of blood by pathogens. Severe immune response to BSI can lead to sepsis, a systemic infection leading to multiple organ dysfunction, coupled with drug resistance, mortality, and limited clinical treatment options. This work aims to further investigate the new interplay between bacterial exocrine regulatory protein and host immune cells in the context of highly drug-resistant malignant BSI. Whether interfering with related regulatory signaling pathways can reverse the inflammatory disorder of immune cells. In-depth analysis of single-cell sequencing results in Septic patients for potential immunodeficiency factors. Analysis of key proteins enriched by host cells and key pathways using proteomics. Cell models and animal models validate the pathological effects of DnaK on T cells, MAITs, macrophages, and osteoclasts. The blood of patients was analyzed for the immunosuppression of T cells and MAITs. We identified that S. maltophilia-DnaK was enriched in immunodeficient T cells. The activation of the JAK2/STAT1 axis initiated the exhaustion of T cells. Septic patients with Gram-negative bacterial infections exhibited deficiencies in MAITs, which correspond to IFN-γ. Cellular and animal experiments confirmed that DnaK could facilitate MAIT depletion and M1 polarization of macrophages. Additionally, Fludarabine mitigated M1 polarization of blood, liver, and spleen in mice. Interestingly, DnaK also repressed osteoclastogenesis of macrophages stimulated by RANKL. S.maltophilia-DnaK prompts the activation of the JAK2/STAT1 axis in T cells and the M1 polarization of macrophages. Targeting the DnaK's crosstalk can be a potentially effective approach for treating the inflammatory disorder in the broad-spectrum drug-resistant BSI.

Adaptive introgression reveals the genetic basis of a sexually selected syndrome in wall lizards

The joint expression of particular colors, morphologies, and behaviors is a common feature of adaptation, but the genetic basis for such "phenotypic syndromes" remains poorly understood. Here, we identified a complex genetic architecture associated with a sexually selected syndrome in common wall lizards, by capitalizing on the adaptive introgression of coloration and morphology into a distantly related lineage. Consistent with the hypothesis that the evolution of phenotypic syndromes in vertebrates is facilitated by developmental linkage through neural crest cells, most of the genes associated with the syndrome are involved in neural crest cell regulation. A major locus was a ~400-kb region, characterized by standing structural genetic variation and previously implied in the evolutionary innovation of coloration and beak size in birds. We conclude that features of the developmental and genetic architecture contribute to maintaining trait integration, facilitating the extensive and rapid introgressive spread of suites of sexually selected characters.

Structural and functional validation of a highly specific Smurf2 inhibitor

Smurf1 and Smurf2 are two closely related member of the HECT (homologous to E6AP carboxy terminus) E3 ubiquitin ligase family and play important roles in the regulation of various cellular processes. Both were initially identified to regulate transforming growth factor-β and bone morphogenetic protein signaling pathways through regulating Smad protein stability and are now implicated in various pathological processes. Generally, E3 ligases, of which over 800 exist in humans, are ideal targets for inhibition as they determine substrate specificity; however, there are few inhibitors with the ability to precisely target a particular E3 ligase of interest. In this work, we explored a panel of ubiquitin variants (UbVs) that were previously identified to bind Smurf1 or Smurf2. In vitro binding and ubiquitination assays identified a highly specific Smurf2 inhibitor, UbV S2.4, which was able to inhibit ligase activity with high potency in the low nanomolar range. Orthologous cellular assays further demonstrated high specificity of UbV S2.4 toward Smurf2 and no cross-reactivity toward Smurf1. Structural analysis of UbV S2.4 in complex with Smurf2 revealed its mechanism of inhibition was through targeting the E2 binding site. In summary, we investigated several protein-based inhibitors of Smurf1 and Smurf2 and identified a highly specific Smurf2 inhibitor that disrupts the E2-E3 protein interaction interface.

Asymmetric and parallel subgenome selection co-shape common carp domestication

BACKGROUND

The common carp (Cyprinus carpio) might best represent the domesticated allopolyploid animals. Although subgenome divergence which is well-known to be a key to allopolyploid domestication has been comprehensively characterized in common carps, the link between genetic architecture underlying agronomic traits and subgenome divergence is unknown in the selective breeding of common carps globally.

RESULTS

We utilized a comprehensive SNP dataset in 13 representative common carp strains worldwide to detect genome-wide genetic variations associated with scale reduction, vibrant skin color, and high growth rate in common carp domestication. We identified numerous novel candidate genes underlie the three agronomically most desirable traits in domesticated common carps, providing potential molecular targets for future genetic improvement in the selective breeding of common carps. We found that independently selective breeding of the same agronomic trait (e.g., fast growing) in common carp domestication could result from completely different genetic variations, indicating the potential advantage of allopolyploid in domestication. We observed that candidate genes associated with scale reduction, vibrant skin color, and/or high growth rate are repeatedly enriched in the immune system, suggesting that domestication of common carps was often accompanied by the disease resistance improvement.

CONCLUSIONS

In common carp domestication, asymmetric subgenome selection is prevalent, while parallel subgenome selection occurs in selective breeding of common carps. This observation is not due to asymmetric gene retention/loss between subgenomes but might be better explained by reduced pleiotropy through transposable element-mediated expression divergence between ohnologs. Our results demonstrate that domestication benefits from polyploidy not only in plants but also in animals.

Similarities in the induction of the intracellular pathogen response in Caenorhabditis elegans and the type I interferon response in mammals

Although the type-I interferon (IFN-I) response is considered vertebrate-specific, recent findings about the Intracellular Pathogen Response (IPR) in nematode Caenorhabditis elegans indicate that there are similarities between these two transcriptional immunological programs. The IPR is induced during infection with natural intracellular fungal and viral pathogens of the intestine and promotes resistance against these pathogens. Similarly, the IFN-I response is induced by viruses and other intracellular pathogens and promotes resistance against infection. Whether the IPR and the IFN-I response evolved in a divergent or convergent manner is an unanswered and exciting question, which could be addressed by further studies of immunity against intracellular pathogens in C. elegans and other simple host organisms. Here we highlight similar roles played by RIG-I-like receptors, purine metabolism enzymes, proteotoxic stressors, and transcription factors to induce the IPR and IFN-I response, as well as the similar consequences of these defense programs on organismal development.

Craniofacial dysmorphology in Down syndrome is caused by increased dosage of Dyrk1a and at least three other genes

Down syndrome (DS), trisomy of human chromosome 21 (Hsa21), occurs in 1 in 800 live births and is the most common human aneuploidy. DS results in multiple phenotypes, including craniofacial dysmorphology, which is characterised by midfacial hypoplasia, brachycephaly and micrognathia. The genetic and developmental causes of this are poorly understood. Using morphometric analysis of the Dp1Tyb mouse model of DS and an associated mouse genetic mapping panel, we demonstrate that four Hsa21-orthologous regions of mouse chromosome 16 contain dosage-sensitive genes that cause the DS craniofacial phenotype, and identify one of these causative genes as Dyrk1a. We show that the earliest and most severe defects in Dp1Tyb skulls are in bones of neural crest (NC) origin, and that mineralisation of the Dp1Tyb skull base synchondroses is aberrant. Furthermore, we show that increased dosage of Dyrk1a results in decreased NC cell proliferation and a decrease in size and cellularity of the NC-derived frontal bone primordia. Thus, DS craniofacial dysmorphology is caused by an increased dosage of Dyrk1a and at least three other genes.

An intersectional analysis of LncRNAs and mRNAs reveals the potential therapeutic targets of Bi Zhong Xiao Decoction in collagen-induced arthritis rats

Background

Bi Zhong Xiao decoction (BZXD), a traditional Chinese herbal formula, has been used clinically for many years to treat rheumatoid arthritis (RA). Both clinical and experimental studies have revealed that BZXD is effective in treating RA, but the mechanism remains unclear. In this study, we aimed to explore the mechanism of efficacy of BZXD through transcriptomic analysis of lncRNA and mRNA.

Methods

The combination method of ultra-high performance liquid chromatography-mass spectrometry/mass spectrometry was used to assess the quality of BZXD. The efficacy of BZXD in treating collagen-induced arthritis (CIA) was evaluated by clinical assessment, weight changes, hematoxylin–eosin and safranin o-fast green staining, and Micro-CT. Arraystar rat lncRNA-mRNA chip technology was used to determine the lncRNA and mRNA expression profiles of the Control, CIA and BZXD groups, and to screen gene expression profiles related to the curative effect of BZXD. A lncRNA-mRNA co-expression network was constructed for the therapeutic efficacy genes. Through GO function and KEGG pathway enrichment analysis, the biological functions and signaling pathways of therapeutic efficacy genes were determined. Based on fold change and functional annotation, key differentially expressed lncRNAs and mRNAs were selected for reverse transcription-quantitative polymerase chain reaction (RT-qPCR) validation. The functions of lncRNAs targeting mRNAs were verified in vitro.

Results

We demonstrated that BZXD could effectively reverse bone erosion. After BZXD treatment, up to 33 lncRNAs and 107 mRNAs differentially expressed genes were reversely regulated by BZXD. These differentially expressed lncRNAs are mainly involved in the biological process of the immune response and are closely related to the ECM-receptor interaction, MAPK signaling pathway, Focal adhesion, Ras signaling pathway, Antigen processing and presentation, and Chemokine signaling pathway. We identified four lncRNAs (uc.361−, ENSRNOT00000092834, ENSRNOT00000089244, ENSRNOT00000084631) and three mRNAs (Acvr2a, Cbx2, Morc4) as potential therapeutic targets for BZXD and their microarray data consistent with the RT-qPCR. In vitro experiments confirmed that silencing the lncRNAs ENSRNOT00000092834 and ENSRNOT00000084631 reversed the expression of target mRNAs.

Conclusions

This study elucidates the possible mechanism of BZXD reversing bone erosion in CIA rats from the perspective of lncRNA and mRNA. To provide a basis and direction for further exploration of the mechanism of BZXD in treating RA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-022-00670-z.

Microrchidia CW-Type Zinc Finger 2, a Chromatin Modifier in a Spectrum of Peripheral Neuropathies

Microrchidia CW-type zinc finger 2 (MORC2) gene encodes a protein expressed in all tissues and enriched in the brain. MORC2 protein is composed of a catalytic ATPase domain, three coil-coiled domains allowing dimerization or protein complex interaction, a zinc-finger CW domain allowing DNA interaction, and a CHROMO-like (CHRromatin Organization Modifier) domain. Recently, de novo or dominantly inherited heterozygous mutations have been associated with a spectrum of disorders affecting the peripheral nervous system such as the Charcot-Marie-Tooth disease, spinal muscular atrophy-like phenotype disorder, or a neurodevelopmental syndrome associated with developmental delay, impaired growth, dysmorphic facies, and axonal neuropathy (DIGFAN). In this review, we detail the various mutations of MORC2 and their consequences on clinical manifestations. Possible genotype-phenotype correlations as well as intra and inter-family variability are discussed. MORC2 molecular functions such as transcriptional modulation, DNA damage repair, and lipid metabolism are then reviewed. We further discuss the impact of MORC2 mutations on the epigenetic landscape in the neuromuscular system and hypothesize probable pathophysiological mechanisms underlying the phenotypic variability observed.

12-Deoxyphorbol-13-Hexadecanoate Abrogates OVX-Induced Bone Loss in Mice and Osteoclastogenesis via Inhibiting ROS Level and Regulating RANKL-Mediated NFATc1 Activation

Osteoporosis is a major health problem in the elderly. Almost every bone can fracture due to the increased bone fragility in osteoporosis, posing a major challenge to public health. 12-Deoxyphorbol-13-hexadecanoate (DHD), one of the main bioactive components of Stellera chamaejasme L. (Lang Du), is considered to have antitumor, antibacterial, and antifungal properties. However, the role of DHD in osteoporosis is still elusive. In this study, we demonstrated for the first time that DHD inhibits the receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis and bone resorption in a dose- and time-dependent manner without exhibiting cytotoxicity in vitro. Mechanistically, we found that DHD not only represses the expression of osteoclasts marker genes by suppressing RANKL-induced mitogen-activated protein kinase (MAPK) and calcium signaling pathways but also scavenges reactive oxygen species (ROS) through enhancing cytoprotective enzymes expression. Furthermore, DHD inhibits the activation of nuclear factor of activated T cells 1 (NFATc1) during RANKL-induced osteoclasts formation. Preclinical studies revealed that DHD protects against bone loss in ovariectomy (OVX) mice. In sum, our data confirmed that DHD could potentially inhibit osteoclastogenesis by abrogating RANKL-induced MAPK, calcium, and NFATc1 signaling pathways and promoting the expression of ROS scavenging enzymes, thereby preventing OVX-induced bone loss. Thus, DHD may act as a novel therapeutic agent to manage osteoporosis.

Structural and Functional Attributes of Microrchidia Family of Chromatin Remodelers

Chromatin remodelers affect the spatio-temporal dynamics of global gene-expression by structurally modulating and/or reorganizing the chromatin. Microrchidia (MORC) family is a relatively new addition to the four well studied families of chromatin remodeling proteins. In this review, we discuss the current understanding of the structural aspects of human MORCs as well as their epigenetic functions. From a molecular and systems-level perspective, we explore their participation in phase-separated structures, possible influence on various biological processes through protein-protein interactions, and potential extra-nuclear roles. We describe how dysregulation/dysfunction of MORCs can lead to various pathological conditions. We conclude by emphasizing the importance of undertaking integrated efforts to obtain a holistic understanding of the various biological roles of MORCs.

Self-guarding of MORC3 enables virulence factor-triggered immunity

Pathogens use virulence factors to inhibit the immune system1. The guard hypothesis2,3 postulates that hosts monitor (or 'guard') critical innate immune pathways such that their disruption by virulence factors provokes a secondary immune response1. Here we describe a 'self-guarded' immune pathway in human monocytes, in which guarding and guarded functions are combined in one protein. We find that this pathway is triggered by ICP0, a key virulence factor of herpes simplex virus type 1, resulting in robust induction of anti-viral type I interferon (IFN). Notably, induction of IFN by ICP0 is independent of canonical immune pathways and the IRF3 and IRF7 transcription factors. A CRISPR screen identified the ICP0 target MORC34 as an essential negative regulator of IFN. Loss of MORC3 recapitulates the IRF3- and IRF7-independent IFN response induced by ICP0. Mechanistically, ICP0 degrades MORC3, which leads to de-repression of a MORC3-regulated DNA element (MRE) adjacent to the IFNB1 locus. The MRE is required in cis for IFNB1 induction by the MORC3 pathway, but is not required for canonical IFN-inducing pathways. As well as repressing the MRE to regulate IFNB1, MORC3 is also a direct restriction factor of HSV-15. Our results thus suggest a model in which the primary anti-viral function of MORC3 is self-guarded by its secondary IFN-repressing function-thus, a virus that degrades MORC3 to avoid its primary anti-viral function will unleash the secondary anti-viral IFN response.

MORC protein family-related signature within human disease and cancer

The microrchidia (MORC) family of proteins is a highly conserved nuclear protein superfamily, whose members contain common domain structures (GHKL-ATPase, CW-type zinc finger and coiled-coil domain) yet exhibit diverse biological functions. Despite the advancing research in previous decades, much of which focuses on their role as epigenetic regulators and in chromatin remodeling, relatively little is known about the role of MORCs in tumorigenesis and pathogenesis. MORCs were first identified as epigenetic regulators and chromatin remodelers in germ cell development. Currently, MORCs are regarded as disease genes that are involved in various human disorders and oncogenes in cancer progression and are expected to be the important biomarkers for diagnosis and treatment. A new paradigm of expanded MORC family function has raised questions regarding the regulation of MORCs and their biological role at the subcellular level. Here, we systematically review the progress of researching MORC members with respect to their domain architectures, diverse biological functions, and distribution characteristics and discuss the emerging roles of the aberrant expression or mutation of MORC family members in human disorders and cancer development. Furthermore, the illustration of related mechanisms of the MORC family has made MORCs promising targets for developing diagnostic tools and therapeutic treatments for human diseases, including cancers.

The role of MORC3 in silencing transposable elements in mouse embryonic stem cells

BACKGROUND

Microrchidia proteins (MORCs) are involved in epigenetic gene silencing in a variety of eukaryotic organisms. Deletion of MORCs result in several developmental abnormalities and their dysregulation has been implicated in developmental disease and multiple cancers. Specifically, mammalian MORC3 mutations are associated with immune system defects and human cancers such as bladder, uterine, stomach, lung, and diffuse large B cell lymphomas. While previous studies have shown that MORC3 binds to H3K4me3 in vitro and overlaps with H3K4me3 ChIP-seq peaks in mouse embryonic stem cells, the mechanism by which MORC3 regulates gene expression is unknown.

RESULTS

In this study, we identified that mutation in Morc3 results in a suppressor of variegation phenotype in a Modifiers of murine metastable epialleles Dominant (MommeD) screen. We also find that MORC3 functions as an epigenetic silencer of transposable elements (TEs) in mouse embryonic stem cells (mESCs). Loss of Morc3 results in upregulation of TEs, specifically those belonging to the LTR class of retrotransposons also referred to as endogenous retroviruses (ERVs). Using ChIP-seq we found that MORC3, in addition to its known localization at H3K4me3 sites, also binds to ERVs, suggesting a direct role in regulating their expression. Previous studies have shown that these ERVs are marked by the repressive histone mark H3K9me3 which plays a key role in their silencing. However, we found that levels of H3K9me3 showed only minor losses in Morc3 mutant mES cells. Instead, we found that loss of Morc3 resulted in increased chromatin accessibility at ERVs as measured by ATAC-seq.

CONCLUSIONS

Our results reveal MORC3 as a novel regulator of ERV silencing in mouse embryonic stem cells. The relatively minor changes of H3K9me3 in the Morc3 mutant suggests that MORC3 acts mainly downstream of, or in a parallel pathway with, the TRIM28/SETDB1 complex that deposits H3K9me3 at these loci. The increased chromatin accessibility of ERVs in the Morc3 mutant suggests that MORC3 may act at the level of chromatin compaction to effect TE silencing.

Morc3 silences endogenous retroviruses by enabling Daxx-mediated histone H3.3 incorporation

Endogenous retroviruses (ERVs) comprise a significant portion of mammalian genomes. Although specific ERV loci feature regulatory roles for host gene expression, most ERV integrations are transcriptionally repressed by Setdb1-mediated H3K9me3 and DNA methylation. However, the protein network which regulates the deposition of these chromatin modifications is still incompletely understood. Here, we perform a genome-wide single guide RNA (sgRNA) screen for genes involved in ERV silencing and identify the GHKL ATPase protein Morc3 as a top-scoring hit. Morc3 knock-out (ko) cells display de-repression, reduced H3K9me3, and increased chromatin accessibility of distinct ERV families. We find that the Morc3 ATPase cycle and Morc3 SUMOylation are important for ERV chromatin regulation. Proteomic analyses reveal that Morc3 mutant proteins fail to interact with the histone H3.3 chaperone Daxx. This interaction depends on Morc3 SUMOylation and Daxx SUMO binding. Notably, in Morc3 ko cells, we observe strongly reduced histone H3.3 on Morc3 binding sites. Thus, our data demonstrate Morc3 as a critical regulator of Daxx-mediated histone H3.3 incorporation to ERV regions.

Endogenous retroviruses (ERVs) compose a significant portion of mammalian genomes; however, how ERVs are regulated is not well known. Here the authors performed a genome-wide sgRNA screen to identify Morc3 as a mediator of ERV silencing. They show Morc3 associates with the H3.3 chaperone Daxx, and that loss of Morc3 leads to reduced H3.3 at ERVs.

Clinical features, treatments and outcomes of calcinosis in adult patients with dermatomyositis: a single cohort study

OBJECTIVE

The occurrence of calcinosis cutis as a clinical feature of dermatomyositis in adult patients is not well understood. Cohort studies of adult patients with calcinosis are rare. We systematically describe the clinical features, treatments and outcomes of adult patients with calcinosis.

METHODS

We initially enrolled 627 adult DM patients. Of those enrolled, 35 (5.6%) were found to have calcinosis. We analysed the clinical features associated with calcinosis in this subgroup. The risk factors associated with calcinosis were analysed using the Poisson regression model.

RESULTS

Multivariate analysis showed that a younger age at disease onset [odds ratio (OR) = 0.945, 95% CI 0.925, 0.966, P < 0.001], dysphagia (OR = 2.609, 95% CI 1.189, 5.728, P = 0.017), skin ulcer (OR = 5.705, 95% CI 3.041, 10.705, P < 0.001) and the presence of anti-nuclear matrix protein 2 antibody (OR = 5.917, 95% CI 2.754, 12.714, P < 0.001) were independently associated with calcinosis. In both the low- and high-dose prednisone treatment groups, no difference in treatment response was seen between the bisphosphonate treatment group and the group not receiving bisphosphonate treatment (P = 1.000 and P = 0.375, respectively). A follow-up study revealed that the mortality rate of the calcinosis group was 5.7%. Additionally, 60.6% of the cases had a chronic polycyclic disease course and 17.1% had mild complications secondary to calcinosis.

CONCLUSION

Calcinosis is an uncommon, but significant clinical feature in adult patients with DM. Bisphosphonates were not found to effectively treat calcinosis, however, the overall health outcomes of adult DM patients with calcinosis were favourable.

Integrating Transcriptome-Wide Association Study and mRNA Expression Profiling Identifies Novel Genes Associated With Osteonecrosis of the Femoral Head

Objective

This study aims to identify novel candidate genes associated with osteonecrosis of the femoral head (ONFH).

Methods

A transcriptome-wide association study (TWAS) was performed by integrating the genome-wide association study dataset of osteonecrosis (ON) in the UK Biobank with pre-computed mRNA expression reference weights of muscle skeleton (MS) and blood. The ON-associated genes identified by TWAS were further subjected to gene ontology (GO) analysis by the DAVID tool. Finally, a trans-omics comparative analysis of TWAS and genome-wide mRNA expression profiling was conducted to identify the common genes and the GO terms shared by both DNA-level TWAS and mRNA-level expression profile for ONFH.

Results

TWAS totally identified 564 genes that were with P_TWAS value <0.05 for MS and blood, such as CBX1 (P_TWAS = 0.0001 for MS), SRPK2 (P_TWAS = 0.0002 for blood), and MYO5A (P_TWAS = 0.0005 for blood). After comparing the genes detected by TWAS with the differentially expressed genes identified by mRNA expression profiling, we detected 59 overlapped genes, such as STEAP4 [P_TWAS = 0.0270, FC (fold change)_mRNA = 7.03], RABEP1 (P_TWAS = 0.010, FC_mRNA = 2.22), and MORC3 (P_TWAS = 0.0053, FC_mRNA = 2.92). The GO analysis of TWAS-identified genes discovered 53 GO terms for ON. Further comparing the GO results of TWAS and mRNA expression profiling identified four overlapped GO terms, including cysteine-type endopeptidase activity (P_TWAS = 0.0006, P_mRNA = 0.0227), extracellular space (P_TWAS = 0.0342, P_mRNA = 0.0012), protein binding (P_TWAS = 0.0112, P_mRNA = 0.0106), and ATP binding (P_TWAS = 0.0464, P_mRNA = 0.0033).

Conclusion

Several ONFH-associated genes and GO terms were identified by integrating TWAS and mRNA expression profiling. It provides novel clues to reveal the pathogenesis of ONFH.

PKC-δ deficiency in B cells displays osteopenia accompanied with upregulation of RANKL expression and osteoclast-osteoblast uncoupling

PKC-δ is an important molecule for B-cell proliferation and tolerance. B cells have long been recognized to play a part in osteoimmunology and pathological bone loss. However, the role of B cells with PKC-δ deficiency in bone homeostasis and the underlying mechanisms are unknown. We generated mice with PKC-δ deletion selectively in B cells by crossing PKC-δ-loxP mice with CD19-Cre mice. We studied their bone phenotype using micro-CT and histology. Next, immune organs were obtained and analyzed. Western blotting was used to determine the RANKL/OPG ratio in vitro in B-cell cultures, ELISA assay and immunohistochemistry were used to analyze in vivo RANKL/OPG balance in serum and bone sections respectively. Finally, we utilized osteoclastogenesis to study osteoclast function via hydroxyapatite resorption assay, and isolated primary calvaria osteoblasts to investigate osteoblast proliferation and differentiation. We also investigated osteoclast and osteoblast biology in co-culture with B-cell supernatants. We found that mice with PKC-δ deficiency in B cells displayed an osteopenia phenotype in the trabecular and cortical compartment of long bones. In addition, PKC-δ deletion resulted in changes of trabecular bone structure in association with activation of osteoclast bone resorption and decrease in osteoblast parameters. As expected, inactivation of PKC-δ in B cells resulted in changes in spleen B-cell number, function, and distribution. Consistently, the RANKL/OPG ratio was elevated remarkably in B-cell culture, in the serum and in bone specimens after loss of PKC-δ in B cells. Finally, in vitro analysis revealed that PKC-δ ablation suppressed osteoclast differentiation and function but co-culture with B-cell supernatant reversed the suppression effect, as well as impaired osteoblast proliferation and function, indicative of osteoclast–osteoblast uncoupling. In conclusion, PKC-δ plays an important role in the interplay between B cells in the immune system and bone cells in the pathogenesis of bone lytic diseases.

A 5-Gene Stemness Score for Rapid Determination of Risk in Multiple Myeloma

Purpose

Risk stratification in patients with multiple myeloma (MM) remains a challenge. As clinicopathological characteristics have been demonstrated insufficient for exactly defining MM risk, and molecular biomarkers have become the focuses of interests. Prognostic predictions based on gene expression profiles (GEPs) have been the most accurate to this day. The purpose of our study was to construct a risk score based on stemness genes to evaluate the prognosis in MM.

Materials and Methods

Bioinformatics studies by ingenuity pathway analyses in side population (SP) and non-SP (MP) cells of MM patients were performed. Firstly, co-expression network was built to confirm hub genes associated with the top five Kyoto Encyclopedia of Genes and Genomes pathways. Functional analyses of hub genes were used to confirm the biologic functions. Next, these selective genes were utilized for construction of prognostic model, and this model was validated in independent testing sets. Finally, five stemness genes (ROCK1, GSK3B, BRAF, MAPK1 and MAPK14) were used to build a MM side population 5 (MMSP5) gene model, which was demonstrated to be forcefully prognostic compared to usual clinical prognostic parameters by multivariate cox analysis. MM patients in MMSP5 low-risk group were significantly related to better prognosis than those in high-risk group in independent testing sets.

Conclusion

Our study provided proof-of-concept that MMSP5 model can be adopted to evaluate recurrence risk and clinical outcome for MM. The MMSP5 model evaluated in different databases clearly indicated novel risk stratification for personalized anti-MM treatments.

Advanced Genetic Approaches in Discovery and Characterization of Genes Involved With Osteoporosis in Mouse and Human

Osteoporosis is a complex condition with contributions from, and interactions between, multiple genetic loci and environmental factors. This review summarizes key advances in the application of genetic approaches for the identification of osteoporosis susceptibility genes. Genome-wide linkage analysis (GWLA) is the classical approach for identification of genes that cause monogenic diseases; however, it has shown limited success for complex diseases like osteoporosis. In contrast, genome-wide association studies (GWAS) have successfully identified over 200 osteoporosis susceptibility loci with genome-wide significance, and have provided most of the candidate genes identified to date. Phenome-wide association studies (PheWAS) apply a phenotype-to-genotype approach which can be used to complement GWAS. PheWAS is capable of characterizing the association between osteoporosis and uncommon and rare genetic variants. Another alternative approach, whole genome sequencing (WGS), will enable the discovery of uncommon and rare genetic variants in osteoporosis. Meta-analysis with increasing statistical power can offer greater confidence in gene searching through the analysis of combined results across genetic studies. Recently, new approaches to gene discovery include animal phenotype based models such as the Collaborative Cross and ENU mutagenesis. Site-directed mutagenesis and genome editing tools such as CRISPR/Cas9, TALENs and ZNFs have been used in functional analysis of candidate genes in vitro and in vivo. These resources are revolutionizing the identification of osteoporosis susceptibility genes through the use of genetically defined inbred mouse libraries, which are screened for bone phenotypes that are then correlated with known genetic variation. Identification of osteoporosis-related susceptibility genes by genetic approaches enables further characterization of gene function in animal models, with the ultimate aim being the identification of novel therapeutic targets for osteoporosis.

Mechanism for autoinhibition and activation of the MORC3 ATPase

Microrchidia 3 (MORC3) is a human protein linked to autoimmune disorders, Down syndrome, and cancer. It is a member of a newly identified family of human ATPases with an uncharacterized mechanism of action. Here, we elucidate the molecular basis for inhibition and activation of MORC3. The crystal structure of the MORC3 region encompassing the ATPase and CW domains in complex with a nonhydrolyzable ATP analog demonstrates that the two domains are directly coupled. The extensive ATPase:CW interface stabilizes the protein fold but inhibits the catalytic activity of MORC3. Enzymatic, NMR, mutational, and biochemical analyses show that in the autoinhibited, off state, the CW domain sterically impedes binding of the ATPase domain to DNA, which in turn is required for the catalytic activity. MORC3 autoinhibition is released by disrupting the intramolecular ATPase:CW coupling through the competitive interaction of CW with histone H3 tail or by mutating the interfacial residues. Binding of CW to H3 leads to a marked rearrangement in the ATPase-CW cassette, which frees the DNA-binding site in active MORC3 (on state). We show that ATP-induced dimerization of the ATPase domain is strictly required for the catalytic activity and that the dimeric form of ATPase-CW might cooperatively bind to dsDNA. Together, our findings uncovered a mechanism underlying the fine-tuned regulation of the catalytic domain of MORC3 by the epigenetic reader, CW.

Differential Clinical Associations of Anti-Nuclear Matrix Protein 2 Autoantibodies in Patients With Idiopathic Inflammatory Myopathies

OBJECTIVE

To investigate the associations between anti-nuclear matrix protein 2 (anti-NXP-2) autoantibody levels and disease activity as well as calcinosis severity in patients with idiopathic inflammatory myopathies (IIMs).

METHODS

Serum levels of anti-NXP-2 autoantibodies were determined in 709 patients with IIMs and also serially measured in the patients' sera with an in-house enzyme-linked immunosorbent assay using MORC3 recombinant protein. Patients with anti-NXP-2 autoantibodies were divided into 2 subgroups: those with and those without calcinosis. Associations of anti-NXP-2 autoantibody levels with organ-specific disease activity (using 10-cm visual analog scale [VAS] scores), serum creatine kinase (CK) levels, and calcinosis severity were investigated in cross-sectional and longitudinal analyses.

RESULTS

A cross-sectional analysis of 56 IIM patients with anti-NXP-2 autoantibodies (38 without calcinosis and 18 with calcinosis) showed that in patients without calcinosis, the levels of anti-NXP-2 autoantibodies were positively correlated with the physician's global assessment of disease activity and muscle VAS scores and serum CK levels, whereas no such association was found in patients with calcinosis. Results of the longitudinal study revealed strong correlations of anti-NXP-2 antibody levels with the physician's global assessment and constitutional, cutaneous, gastrointestinal, and muscle VAS scores and serum CK levels in patients without calcinosis, but in patients with calcinosis, only a moderate correlation was observed between anti-NXP-2 antibody levels and the physician's global VAS and constitutional VAS scores. Of note, in patients without calcinosis, anti-NXP-2 autoantibodies were found to disappear during periods of clinical remission, but reappeared with disease relapse. No association between anti-NXP-2 antibody levels and the severity of calcinosis was observed.

CONCLUSION

These findings indicate that anti-NXP-2 autoantibodies serve as a useful marker for disease activity in patients with IIMs, especially in the absence of calcinosis. The differential associations observed between anti-NXP-2 autoantibody levels and disease activity suggest that there may be a phenotypic difference between patients with and those without calcinosis.

Shape-Shifted Red Blood Cells: A Novel Red Blood Cell Stage?

Primitive nucleated erythroid cells in the bloodstream have long been suggested to be more similar to nucleated red cells of fish, amphibians, and birds than the red cells of fetal and adult mammals. Rainbow trout Ficoll-purified red blood cells (RBCs) cultured in vitro undergo morphological changes, especially when exposed to stress, and enter a new cell stage that we have coined shape-shifted RBCs (shRBCs). We have characterized these shRBCs using transmission electron microscopy (TEM) micrographs, Wright–Giemsa staining, cell marker immunostaining, and transcriptomic and proteomic evaluation. shRBCs showed reduced density of the cytoplasm, hemoglobin loss, decondensed chromatin in the nucleus, and striking expression of the B lymphocyte molecular marker IgM. In addition, shRBCs shared some features of mammalian primitive pyrenocytes (extruded nucleus surrounded by a thin rim of cytoplasm and phosphatidylserine (PS) exposure on cell surface). These shRBCs were transiently observed in heat-stressed rainbow trout bloodstream for three days. Functional network analysis of combined transcriptomic and proteomic studies resulted in the identification of proteins involved in pathways related to the regulation of cell morphogenesis involved in differentiation, cellular response to stress, and immune system process. In addition, shRBCs increased interleukin 8 (IL8), interleukin 1 β (IL1β), interferon ɣ (IFNɣ), and natural killer enhancing factor (NKEF) protein production in response to viral hemorrhagic septicemia virus (VHSV). In conclusion, shRBCs may represent a novel cell stage that participates in roles related to immune response mediation, homeostasis, and the differentiation and development of blood cells.

MORC2B is essential for meiotic progression and fertility

The microrchidia (MORC) family proteins are chromatin-remodelling factors and function in diverse biological processes such as DNA damage response and transposon silencing. Here, we report that mouse Morc2b encodes a functional germ cell-specific member of the MORC protein family. Morc2b arose specifically in the rodent lineage through retrotransposition of Morc2a during evolution. Inactivation of Morc2b leads to meiotic arrest and sterility in both sexes. Morc2b-deficient spermatocytes and oocytes exhibit failures in chromosomal synapsis, blockades in meiotic recombination, and increased apoptosis. Loss of MORC2B causes mis-regulated expression of meiosis-specific genes. Furthermore, we find that MORC2B interacts with MORC2A, its sequence paralogue. Our results demonstrate that Morc2b, a relatively recent gene, has evolved an essential role in meiosis and fertility.

In sexually reproducing organisms, meiosis, a process unique to germ cells, produces haploid gametes. Abnormalities in meiosis can lead to infertility, loss of pregnancy, or genetic diseases such as Down syndrome. The meiotic processes are tightly regulated by a large number of genes including many meiosis-specific ones. The majority of meiosis-specific factors are conserved, however, species-specific factors have evolved. Here we report functional studies of a rodent lineage–specific gene named Morc2b. Morc2b belongs to a family of chromatin-remodelling factors. Morc2b is specifically expressed in germ cells. Disruption of Morc2b causes meiotic arrest and infertility in both sexes. Notably, MORC2B regulates the expression of a number of meiosis-specific genes. Interestingly, MORC2B interacts with its sequence homologue MORC2A. These functional studies have uncovered a new protein complex in the regulation of key meiotic processes and suggested the presence of continued selection pressure for evolution of new meiosis-specific factors.

Dermatomyositis and Immune-Mediated Necrotizing Myopathies: A Window on Autoimmunity and Cancer

Autoimmune myopathies (myositides) are strongly associated with malignancy. The link between myositis and cancer, originally noticed by Bohan and Peter in their classification in 1975 (1), has been evidenced by large population-based cohort studies and a recent meta-analysis. The numerous reports of cases in which the clinical course of myositis reflects that of cancer and the short delay between myositis and cancer onset support the notion that myositis may be an authentic paraneoplastic disorder. Thus, cancer-associated myositis raises the question of cancer as a cause rather than a consequence of autoimmunity. Among myositides, dermatomyositis and more recently, although to a lesser extent, immune-mediated necrotizing myopathies are the most documented forms associated with cancer. Interestingly, the current diagnostic approach for myositis is based on the identification of specific antibodies where each antibody determines specific clinical features and outcomes. Recent findings have shown that the autoantibodies anti-TIF1γ, anti-NXP2 and anti-HMGCR are associated with cancers in the course of myositis. Herein, we highlight the fact that the targets of these three autoantibodies involve cellular pathways that intervene in tumor promotion and we discuss the role of cancer mutations as autoimmunity triggers in adult myositis.

The Role of MicroRNA-143-5p in the Differentiation of Dental Pulp Stem Cells into Odontoblasts by Targeting Runx2 via the OPG/RANKL Signaling Pathway

This study aims to elucidate the mechanisms by which microRNA-143-5p (miR-143-5p) targets runt-related transcription factor 2 (Runx2) in the differentiation of dental pulp stem cells (DPSCs) into odontoblasts, through regulating the osteoprotegerin receptor activator of the nuclear factor-κB ligand (OPG/RANKL) signaling pathway. Following transfection, DPSCs were divided into blank, control, miR-143-5p mimics, miR-143-5p inhibitors, miR-143-5p inhibitors + siRunx2 and siRunx2 groups. Alkaline phosphatase (ALP) activity and mineralized nodules were detected using ALP kit and alizarin red staining. Quantitative reverse transcriptase real time PCR (qRT-PCR) was conducted to measure mRNA expressions of miR-143-5p, Runx2, OPG, and RANKL. Western blotting was used to assess protein expression of odontoblast differentiation-related proteins. Transwell assay and an extracellular matrix (ECM) adhesion cell assay were employed to examine cell migration and cell adhesion. Compared with the blank group, the miR-143-5p mimics and siRunx2 groups showed decreased ALP activity, decreased mineralized nodules and displays of calcium. Fewer migrated cells, weakened cell adhesion, decreased protein expression of dentin phosphoprotein (DPP), dentin sialoprotein (DSP), dentin matrix protein 1 (DMP1), osteopontin (OPN), bone sialoprotein (BSP), osteocalcin (OCN), OPG and Runx2, and increased RANKL protein expressions were observed. Additionally, opposite results were observed in the miR-143-5p inhibitors group, demonstrating that down-regulated miR-143-5p promotes the differentiation of DPSCs into odontoblasts by enhancing Runx2 expression via the OPG/RANKL signaling pathway. Based on findings in this study, it is postulated that the enhancement of Runx2 expression via the regulation of the OPG/RANKL signaling pathway could be a beneficial approach for dental pulp regeneration. J. Cell. Biochem. 119: 536-546, 2018. © 2017 Wiley Periodicals, Inc.

MORC Proteins: Novel Players in Plant and Animal Health

Microrchidia (MORC) proteins comprise a family of proteins that have been identified in prokaryotes and eukaryotes. They are defined by two hallmark domains: a GHKL-type ATPase and an S5 fold. MORC proteins in plants were first discovered via a genetic screen for Arabidopsis mutants compromised for resistance to a viral pathogen. Subsequent studies expanded their role in plant immunity and revealed their involvement in gene silencing and transposable element repression. Emerging data suggest that MORC proteins also participate in pathogen-induced chromatin remodeling and epigenetic gene regulation. In addition, biochemical analyses recently demonstrated that plant MORCs have topoisomerase II (topo II)-like DNA modifying activities that may be important for their function. Interestingly, animal MORC proteins exhibit many parallels with their plant counterparts, as they have been implicated in disease development and gene silencing. In addition, human MORCs, like plant MORCs, bind salicylic acid and this inhibits some of their topo II-like activities. In this review, we will focus primarily on plant MORCs, although relevant comparisons with animal MORCs will be provided.

The Emerging Role of MORC Family Proteins in Cancer Development and Bone Homeostasis

Microrchidia (MORC or MORC family CW-type zinc finger protein), a highly conserved nuclear protein superfamily, is an interesting new player in signaling-dependent chromatin remodeling and epigenetic regulation. MORC family proteins consist of MORC1, MORC2, MORC3, and MORC4 which display common structural determinants such as CW-type zinc finger and coiled-coil domains. They also exhibit unique structural motifs and tissue-specific expression profiles. MORC1 was first discovered as a key regulator for male meiosis and spermatogenesis. Accumulating biochemical and functional analyses unveil MORC proteins as key regulators for cancer development. More recently, using an ENU mutagenesis mouse model, MORC3 was found to play a role in regulating bone and calcium homeostasis. Here we discuss recent research progress on the emerging role of MORC proteins in cancer development and bone metabolism. Unravelling the cellular and molecular mechanisms by which MORC proteins carry out their functions in a tissue specific manner are important subjects for future investigation. J. Cell. Physiol. 232: 928-934, 2017. © 2016 Wiley Periodicals, Inc.