Zinc finger transcription factors in skeletal development

The Role of Aryl Hydrocarbon Receptor in Bone Biology

Aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor, is crucial in maintaining the skeletal system. Our study focuses on encapsulating the role of AhR in bone biology and identifying novel signaling pathways in musculoskeletal pathologies using the GEO dataset. The GEO2R analysis identified 8 genes (CYP1C1, SULT6B1, CYB5A, EDN1, CXCR4B, CTGFA, TIPARP, and CXXC5A) involved in the AhR pathway, which play a pivotal role in bone remodeling. The AhR knockout in hematopoietic stem cells showed alteration in several novel bone-related transcriptomes (eg, Defb14, ZNF 51, and Chrm5). Gene Ontology Enrichment Analysis demonstrated 54 different biological processes associated with bone homeostasis. Mainly, these processes include bone morphogenesis, bone development, bone trabeculae formation, bone resorption, bone maturation, bone mineralization, and bone marrow development. Employing Functional Annotation and Clustering through DAVID, we further uncovered the involvement of the xenobiotic metabolic process, p450 pathway, oxidation-reduction, and nitric oxide biosynthesis process in the AhR signaling pathway. The conflicting evidence of current research of AhR signaling on bone (positive and negative effects) homeostasis may be due to variations in ligand binding affinity, binding sites, half-life, chemical structure, and other unknown factors. In summary, our study provides a comprehensive understanding of the underlying mechanisms of the AhR pathway in bone biology.

A novel GLI3 frameshift mutation in a Chinese pedigree with polydactyly: A case report

Background

GLI3 gene mutations can result in various forms of polysyndactyly, such as Greig cephalopolysyndactyly syndrome (GCPS, MIM: #175700), Pallister-Hall syndrome (PHS, MIM: #146510), and isolated polydactyly (IPD, MIM: #174200, #174700). Reports on IPD-associated GLI3 mutations are rare. In this study, a novel GLI3 mutation was identified in a Chinese family with IPD.

Results

We report a family with six members affected by IPD. The family members demonstrated several special phenotypes, including sex differences, abnormal finger joint development, and different polydactyly types. We identified a novel frameshift variant in the GLI3 gene (NM_000168.6: c.1820_1821del, NP_000159.3: p.Tyr607Cysfs*9) by whole-exome sequencing. Further analysis suggested that this mutation was the cause of polydactyly in this family.

Conclusions

The discovery of this novel frameshift variant in our study further solidifies the relationship between IPD and GLI3 and expands the previously established spectrum of GLI3 mutations and associated phenotypes.

The Distribution and Biogenic Origins of Zinc in the Mineralised Tooth Tissues of Modern and Fossil Hominoids: Implications for Life History, Diet and Taphonomy

Zinc is incorporated into enamel, dentine and cementum during tooth growth. This work aimed to distinguish between the processes underlying Zn incorporation and Zn distribution. These include different mineralisation processes, the physiological events around birth, Zn ingestion with diet, exposure to the oral environment during life and diagenetic changes to fossil teeth post-mortem. Synchrotron X-ray Fluorescence (SXRF) was used to map zinc distribution across longitudinal polished ground sections of both deciduous and permanent modern human, great ape and fossil hominoid teeth. Higher resolution fluorescence intensity maps were used to image Zn in surface enamel, secondary dentine and cementum, and at the neonatal line (NNL) and enamel-dentine-junction (EDJ) in deciduous teeth. Secondary dentine was consistently Zn-rich, but the highest concentrations of Zn (range 197-1743 ppm) were found in cuspal, mid-lateral and cervical surface enamel and were similar in unerupted teeth never exposed to the oral environment. Zinc was identified at the NNL and EDJ in both modern and fossil deciduous teeth. In fossil specimens, diagenetic changes were identified in various trace element distributions but only demineralisation appeared to markedly alter Zn distribution. Zinc appears to be tenacious and stable in fossil tooth tissues, especially in enamel, over millions of years.

PTH regulates osteogenesis and suppresses adipogenesis through Zfp467 in a feed-forward, PTH1R-cyclic AMP-dependent manner

Conditional deletion of the PTH1R in mesenchymal progenitors reduces osteoblast differentiation, enhances marrow adipogenesis, and increases zinc finger protein 467 (Zfp467) expression. In contrast, genetic loss of Zfp467 increased Pth1r expression and shifts mesenchymal progenitor cell fate toward osteogenesis and higher bone mass. PTH1R and ZFP467 could constitute a feedback loop that facilitates PTH-induced osteogenesis and that conditional deletion of Zfp467 in osteogenic precursors would lead to high bone mass in mice. Prrx1Cre; Zfp467fl/fl but not AdipoqCre; Zfp467fl/fl mice exhibit high bone mass and greater osteogenic differentiation similar to the Zfp467-/- mice. qPCR results revealed that PTH suppressed Zfp467 expression primarily via the cyclic AMP/PKA pathway. Not surprisingly, PKA activation inhibited the expression of Zfp467 and gene silencing of Pth1r caused an increase in Zfp467 mRNA transcription. Dual fluorescence reporter assays and confocal immunofluorescence demonstrated that genetic deletion of Zfp467 resulted in higher nuclear translocation of NFκB1 that binds to the P2 promoter of the Pth1r and increased its transcription. As expected, Zfp467-/- cells had enhanced production of cyclic AMP and increased glycolysis in response to exogenous PTH. Additionally, the osteogenic response to PTH was also enhanced in Zfp467-/- COBs, and the pro-osteogenic effect of Zfp467 deletion was blocked by gene silencing of Pth1r or a PKA inhibitor. In conclusion, our findings suggest that loss or PTH1R-mediated repression of Zfp467 results in a pathway that increases Pth1r transcription via NFκB1 and thus cellular responsiveness to PTH/PTHrP, ultimately leading to enhanced bone formation.

Regulation of human ZNF687, a gene associated with Paget's disease of bone

Mutations in Zinc finger 687 (ZNF687) were associated with Paget's disease of bone (PDB), a disease characterized by increased bone resorption and excessive bone formation. It was suggested that ZNF687 plays a role in bone differentiation and development. However, the mechanisms involved in ZNF687 regulation remain unknown. This study aimed to obtain novel knowledge regarding ZNF687 transcriptional and epigenetic regulation. Through in silico analysis, we hypothesized three ZNF687 promoter regions located upstream exon 1 A, 1B, and 1 C and denominated promoter regions 1, 2, and 3, respectively. Their functionality was confirmed by luciferase activity assays and positive/negative regulatory regions were identified using promoter deletions constructs. In silico analysis revealed a high density of CpG islands in these promoter regions and in vitro methylation suppressed promoters' activity. Using bioinformatic approaches, bone-associated transcription factor binding sites containing CpG dinucleotides were identified, including those for NFκB, PU.1, DLX5, and SOX9. By co-transfection in HEK293 and hFOB cells, we found that DLX5 specifically activated ZNF687 promoter region 1, and its methylation impaired DLX5-driven promoter stimulation. NFκB repressed and activated promoter regions 1 and 2, respectively, and these activities were affected by methylation. PU.1 induced ZNF687 promoter region 1 which was affected by methylation. SOX9 differentially regulated ZNF687 promoters in HEK293 and hFOB cells that were impaired after methylation. In conclusion, this study provides novel insights into ZNF687 regulation by demonstrating that NFκB, PU.1, DLX5, and SOX9 are regulators of ZNF687 promoters, and DNA methylation influences their activity. The contribution of the dysregulation of these mechanisms in PDB should be further elucidated.

Severe Zinc Deficiency Impairs Accrual of Bone in Rapidly Growing Rats That Is Partially Corrected Following Short-term Zinc Repletion

Zinc (Zn) deficiency impairs bone growth. However, the precise skeletal effects of varying levels of Zn deficiency and response to subsequent Zn repletion on the growing skeleton are incompletely understood. To address this gap in knowledge, we investigated the effects of dietary Zn ((severe deficiency (< 0.5 mg Zn/kg diet) and short-term Zn repletion (30 mg/kg diet), marginal deficiency (6 mg Zn/kg diet)) on bone mass, density, and cortical and cancellous bone microarchitecture in growing male Sprague Dawley rats. Marginal Zn intake for 42 days had no effect on bone mass or cortical and cancellous bone microarchitecture. Twenty-one days of severe Zn deficiency lowered serum osteocalcin and C terminal telopeptide of type I collagen (CTX-1), decreased tibial bone mineral content and density, and lowered cross-sectional volume, cortical volume, and cortical thickness in tibial diaphysis as compared to both Zn-adequate (30 mg/kg diet) and pair-fed controls. Severe Zn deficiency similarly lowered cancellous bone volume in proximal tibial metaphysis. Zn repletion (10 days) accelerated weight gain, indicative of catch-up growth, normalized CTX-1 and osteocalcin, but did not normalize bone mass (unadjusted and adjusted for body weight) or cortical and cancellous bone microarchitecture. In summary, severe but not marginal Zn deficiency in rapidly growing rats impaired acquisition of cortical and cancellous bone, resulting in abnormalities in bone microarchitecture. Zn repletion accelerated weight gain compared to Zn-adequate controls but absence of a compensatory increase in serum osteocalcin or bone mass suggests Zn repletion may be insufficient to fully counteract the detrimental effects of prior Zn deficiency on skeletal growth.

Genome-wide association study identifying genetic variants associated with carcass backfat thickness, lean percentage and fat percentage in a four-way crossbred pig population using SLAF-seq technology

Background

Carcass backfat thickness (BFT), carcass lean percentage (CLP) and carcass fat percentage (CFP) are important to the commercial pig industry. Nevertheless, the genetic architecture of BFT, CLP and CFP is still elusive. Here, we performed a genome-wide association study (GWAS) based on specific-locus amplified fragment sequencing (SLAF-seq) to analyze seven fatness-related traits, including five BFTs, CLP, and CFP on 223 four-way crossbred pigs.

Results

A total of 227, 921 highly consistent single nucleotide polymorphisms (SNPs) evenly distributed throughout the genome were used to perform GWAS. Using the mixed linear model (MLM), a total of 20 SNP loci significantly related to these traits were identified on ten Sus scrofa chromosomes (SSC), of which 10 SNPs were located in previously reported quantitative trait loci (QTL) regions. On SSC7, two SNPs (SSC7:29,503,670 and rs1112937671) for average backfat thickness (ABFT) exceeded 1% and 10% Bonferroni genome-wide significance levels, respectively. These two SNP loci were located within an intron region of the COL21A1 gene, which was a protein-coding gene that played an important role in the porcine backfat deposition by affecting extracellular matrix (ECM) remodeling. In addition, based on the other three significant SNPs on SSC7, five candidate genes, ZNF184, ZNF391, HMGA1, GRM4 and NUDT3 were proposed to influence BFT. On SSC9, two SNPs for backfat thickness at 6–7 ribs (67RBFT) and one SNP for CLP were in the same locus region (19 kb interval). These three SNPs were located in the PGM2L1 gene, which encoded a protein that played an indispensable role in glycogen metabolism, glycolysis and gluconeogenesis as a key enzyme. Finally, one significant SNP on SSC14 for CLP was located within the PLBD2 gene, which participated in the lipid catabolic process.

Conclusions

A total of two regions on SSC7 and SSC9 and eight potential candidate genes were found for fatness-related traits in pigs. The results of this GWAS based on SLAF-seq will greatly advance our understanding of the genetic architecture of BFT, CLP, and CFP traits. These identified SNP loci and candidate genes might serve as a biological basis for improving the important fatness-related traits of pigs.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08827-8.

The role of Zfp467 in mediating the pro-osteogenic and anti-adipogenic effects on bone and bone marrow niche

Conditional deletion of the PTH receptor (Pth1r) in mesenchymal progenitors reduces osteoblast differentiation and bone mass while enhancing adipogenesis and bone marrow adipose tissue. Mechanistically, PTH suppresses the expression of Zfp467, a pro-adipogenic zinc finger transcription factor. Consequently, Pth1r deficiency in mesenchymal progenitors leads to increased Zfp467 expression. Based on these observations, we hypothesized that genetic loss of Zfp467 would lead to a shift in marrow progenitor cell fate towards osteogenesis and increased bone mass. To test this hypothesis, we generated Zfp467-/- mice. Zfp467-/- mice (-/-) were significantly smaller than Zfp467+/+ mice (+/+). μCT showed significantly higher trabecular bone and cortical bone area in -/- vs. +/+, and histomorphometry showed higher structural and dynamic formation parameters in -/- mice vs. +/+. Femoral gene expression including Alpl, Sp7, and Acp5 were increased in -/-mice, whereas Adiponectin, Cebpa, Lepr, and Ppraγ mRNA were lower in -/- mice. Similarly, Fabp4 and Lep in the inguinal depot were also decreased in -/- mice. Moreover, marrow adipocyte numbers were reduced in -/- vs +/+ mice (p<0.007). In vitro, COBs and BMSCs-/- showed more positive ALP and Alizarin Red staining and a decrease in ORO droplets. Pth1r mRNA and protein levels were increased in COBs and BMSCs from -/- mice vs +/+ (p<0.02 for each parameter, -/- vs. +/+). -/- cells also exhibited enhanced endogenous levels of cAMP vs. control cells. Moreover, in an ovariectomy (OVX) mouse model, Zfp467-/- mice had significantly lower fat mass but similar bone mass compared to OVX +/+ mice. In contrast, in a high fat diet (HFD) mouse model, in addition to reduced adipocyte volume and adipogenesis related gene expression in both peripheral and bone marrow fat tissue, greater osteoblast number and higher osteogenesis related gene expression were also observed in -/- HFD mice vs. +/+ HFD mice. Taken together, these results demonstrate that ZFP467 negatively influences skeletal homeostasis and favors adipogenesis. Global deletion of Zfp467 increases PTHR1, cAMP and bone turnover, hence its repression is a component of PTH signaling and its regulation. These data support a critical role for Zfp467 in early lineage allocation and provide a novel potential mechanism by which PTH acts in an anabolic manner on the bone remodeling unit.

Mechanoadaptive strain and functional osseointegration of dental implants in rats

Spatiotemporal implant-bone biomechanics and mechanoadaptive strains in peri-implant tissue are poorly understood. Physical and chemical characteristics of an implant-bone complex (IBC) were correlated in three-dimensional space (along the length and around a dental implant) to gather insights into time related integration of the implant with the cortical portion of a jaw bone in a rat. Rats (N = 9) were divided into three experimental groups with three rats per time point; 3-, 11-, and 24-day. All rats were fed crumbled hard pellets mixed with water (soft-food diet) for the first 3 days followed by a hard-food diet with intact hard-food pellets (groups of 11- and 24-day only). Biomechanics of the IBCs harvested from rats at each time point was evaluated by performing mechanical testing in situ in tandem with X-ray imaging. The effect of physical association (contact area) of a loaded implant with adapting peri-implant tissue, and resulting strain within was mapped by using digital volume correlation (DVC) technique. The IBC stiffness at respective time points was correlated with mechanical strain in peri-implant tissue. Results illustrated that IBC stiffness at 11-day was lower than that observed at 3-day. However, at 24-day, IBC stiffness recovered to that which was observed at 3-day. Correlative microscopy and spectroscopy illustrated that the lower IBC stiffness was constituted by softer and less mineralized peri-implant tissue that contained varying expressions of osteoconductive elements. Lower IBC stiffness observed at 11-day was constituted by less mineralized peri-implant tissue with osteoconductive elements that included phosphorus (P) which was co-localized with higher expression of zinc (Zn), and lower expression of calcium (Ca). Higher IBC stiffness at 24-day was constituted by mineralized peri-implant tissue with higher expressions of osteoconductive elements including Ca and P, and lower expressions of Zn. These spatiotemporal correlative maps of peri-implant tissue architecture, heterogeneous distribution of mineral density, and elemental colocalization underscore mechanoadaptive physicochemical properties of peri-implant tissue that facilitate functional osseointegration of an implant. These results provided insights into 1) plausible "prescription" of mechanical loads as an osteoinductive "therapeutic dose" to encourage osteoconductive elements in the peri-implant tissue that would facilitate functional osseointegration of the implant; 2) a "critical temporal window" between 3 and 11 days, and perhaps it is this acute phase during which key candidate regenerative molecules can be harnessed to accelerate osseointegration of an implant under load.

Zinc concentrations in teeth of female walruses reflect the onset of reproductive maturity

Age at maturity is an important parameter in many demographic models and, for some species, can be difficult to obtain using traditional methods. Incremental growth structures act as biological archives, recording information throughout an organism's life and possibly allowing for the reconstruction of life history events. Concentrations of zinc (Zn) in animal tissues are known to be linked to life history, physiology and reproduction and may be retained in incremental growth structures. This study reconstructed lifetime Zn concentrations in teeth (n = 93) of female Pacific walruses (Odobenus rosmarus divergens) collected from 1932-2016. Zn displayed a characteristic pattern of accumulation, with a change point marking the beginning of a lifelong, linear increase in Zn concentrations. We hypothesized that this change point marks the onset of reproductive maturity. The age at which the change point occurred (age_cp) was estimated by counting tooth cementum growth layers. These estimates closely matched literature values of timing of first ovulation in female walruses. Total number of ovulations (estimated from ovary corpora counts from paired tooth/ovary specimens) was closely related to reproductive lifespan (total lifespan - age_cp; R² = 0.70). Further, age_cp tracked changes in Pacific walrus population size as a proportion of carrying capacity, decreasing when the population was depleted by commercial hunting and peaking when carrying capacity was exceeded. This novel approach will aid walrus management, and is likely applicable to other species, offering a potentially powerful tool for research, management and conservation of wildlife populations.

TMT-labeled quantitative proteomic analyses on the longissimus dorsi to identify the proteins underlying intramuscular fat content in pigs

The Laiwu pig is famous for its excessively extremely high level of intramuscular fat content (IMF), however, the exact regulatory mechanism underlying intramuscular fat deposition in skeletal muscle is still unknown. As an economically important trait in pigs, IMF is controlled by multiple genes and biological pathways. In this study, we performed an integrated transcriptome-assisted TMT-labeled quantitative proteomic analysis of the longissimus dorsi (LD) muscle in Laiwu pigs at the fastest IMF deposition stage and identified 5074 unique proteins and 52 differentially abundant proteins (DAPs) (>1.5-fold cutoff, p < .05). These DAPs were hierarchically clustered in the LD muscle over two developmental stages from 120 d to 240 d. A comparison between transcriptomic (mRNA) and proteomic data revealed two differentially expressed genes corresponding to the DAPs. Changes in the levels of the nine proteins were further analyzed using RT-qPCR and parallel reaction monitoring (PRM). The proteins identified in this study could serve as candidates for elucidating the molecular mechanism of IMF deposition in pigs. SIGNIFICANCE: The intramuscular fat content (IMF) refers to the amount of fat within muscles and plays an important role in meat quality by affecting meat quality-related traits, such as tenderness, juiciness and flavor. Using the integrated transcriptome-assisted TMT-labeled quantitative proteomic approach to characterize changes in the proteomic profile of the longissimus dorsi muscle, we identified differentially abundant proteins, such as ALDH1B1, OTX2, AnxA6 and Zfp512, that are associated with intramuscular fat deposition and fat biosynthesis in pigs. These proteins could serve as candidates for elucidating the molecular mechanism of IMF deposition in pigs.

Zinc finger protein transcription factors: Integrated line of action for plant antimicrobial activity

The plants resist/tolerate unfavorable conditions in their natural habitats by using different but aligned and integrated defense mechanisms. Such defense responses include not only morphological and physiological adaptations but also the genomic and transcriptomic reconfiguration. Microbial attack on plants activates multiple pro-survival pathways such as transcriptional reprogramming, hypersensitive response (HR), antioxidant defense system and metabolic remodeling. Up-regulation of these processes during biotic stress conditions directly relates with plant survival. Over the years, hundreds of plant transcription factors (TFs) belonging to diverse families have been identified. Zinc finger protein (ZFP) TFs have crucial role in phytohormone response, plant growth and development, stress tolerance, transcriptional regulation, RNA binding and protein-protein interactions. Recent research progress has revealed regulatory and biological functions of ZFPs in incrementing plant resistance to pathogens. Integration of transcriptional activity with metabolic modulations has miniaturized plant innate immunity. However, the precise roles of different zinc finger TFs in plant immunity to pathogens have not been thoroughly analyzed. This review consolidates the pivotal functioning of zinc finger TFs and proposes the integrative understanding as foundation for the plant growth and development including the stress responses.

The Prevalence and Implication of Zinc Deficiency in Patients With Chronic Liver Disease

Background

Patients with liver cirrhosis often exhibit zinc deficiency. Although zinc is involved in many bioactivities, many aspects of clinical implications of zinc deficiency in liver cirrhosis remain unclear. We aimed to reveal the prevalence and implications of zinc deficiency in liver cirrhosis by assessing associations with parameters such as clinical symptoms and laboratory data.

Methods

In 235 cirrhosis patients enrolled at multiple medical institutions in 2009, we assessed how blood zinc levels were associated with their clinical symptoms, patients characteristics, and liver function test results.

Results

Blood zinc levels were most strongly correlated with blood albumin levels among the study parameters (r = 0.587, P < 0.0001). When blood albumin levels were ≤ 3.5 g/dL, blood zinc levels were < 70 μg/dL in 88% of patients. Additionally, significant correlations were observed with age (r = -0.253, P = 0.0014), aspartate aminotransferase levels (r = -0.254, P = 0.0020), total bilirubin levels (r = -0.222, P = 0.0053), prothrombin time (r = -0.255, P = 0.0029), branched-chain amino acid to tyrosine ratio (r = 0.357, P < 0.0001), Child-Pugh score (r = 0.469, P < 0.0001), ammonia levels (r = -0.246, P = 0.0028), and total cholesterol levels (r = 0.314, P < 0.0001). Blood zinc levels were significantly lower in patients with edema/ascites (P < 0.0001), those with hepatic encephalopathy (P = 0.0215), those receiving oral diuretics (P = 0.0045), and those receiving oral branched-chain amino acids (P < 0.0001) than in those without these conditions.

Conclusions

Zinc deficiency is prevalent in cirrhosis patients, whereas nitrogen metabolic disorders, particularly hypoalbuminemia, can be an indicator of zinc deficiency. Thus, cirrhosis patients exhibiting a nitrogen metabolic disorder should be examined for the presence of zinc deficiency.

Transcriptional signature of lymphoblastoid cell lines of BRCA1, BRCA2 and non-BRCA1/2 high risk breast cancer families

Approximately 25% of hereditary breast cancer cases are associated with a strong familial history which can be explained by mutations in BRCA1 or BRCA2 and other lower penetrance genes. The remaining high-risk families could be classified as BRCAX (non-BRCA1/2) families.

Gene expression involving alternative splicing represents a well-known mechanism regulating the expression of multiple transcripts, which could be involved in cancer development. Thus using RNA-seq methodology, the analysis of transcriptome was undertaken to potentially reveal transcripts implicated in breast cancer susceptibility and development.

RNA was extracted from immortalized lymphoblastoid cell lines of 117 women (affected and unaffected) coming from BRCA1, BRCA2 and BRCAX families. Anova analysis revealed a total of 95 transcripts corresponding to 85 different genes differentially expressed (Bonferroni corrected p-value <0.01) between those groups. Hierarchical clustering allowed distinctive subgrouping of BRCA1/2 subgroups from BRCAX individuals. We found 67 transcripts, which could discriminate BRCAX from BRCA1/BRCA2 individuals while 28 transcripts discriminate affected from unaffected BRCAX individuals.

To our knowledge, this represents the first study identifying transcripts differentially expressed in lymphoblastoid cell lines from major classes of mutation-related breast cancer subgroups, namely BRCA1, BRCA2 and BRCAX. Moreover, some transcripts could discriminate affected from unaffected BRCAX individuals, which could represent potential therapeutic targets for breast cancer treatment.

Association of human height-related genetic variants with familial short stature in Han Chinese in Taiwan

Human height can be described as a classical and inherited trait model. Genome-wide association studies (GWAS) have revealed susceptible loci and provided insights into the polygenic nature of human height. Familial short stature (FSS) represents a suitable trait for investigating short stature genetics because disease associations with short stature have been ruled out in this case. In addition, FSS is caused only by genetically inherited factors. In this study, we explored the correlations of FSS risk with the genetic loci associated with human height in previous GWAS, alone and cumulatively. We systematically evaluated 34 known human height single nucleotide polymorphisms (SNPs) in relation to FSS in the additive model (p < 0.00005). A cumulative effect was observed: the odds ratios gradually increased with increasing genetic risk score quartiles (p < 0.001; Cochran-Armitage trend test). Six affected genes-ZBTB38, ZNF638, LCORL, CABLES1, CDK10, and TSEN15-are located in the nucleus and have been implicated in embryonic, organismal, and tissue development. In conclusion, our study suggests that 13 human height GWAS-identified SNPs are associated with FSS risk both alone and cumulatively.

Gene Expression Profiling of Muscle Stem Cells Identifies Novel Regulators of Postnatal Myogenesis

Skeletal muscle growth and regeneration require a population of muscle stem cells, the satellite cells, located in close contact to the myofiber. These cells are specified during fetal and early postnatal development in mice from a Pax3/7 population of embryonic progenitor cells. As little is known about the genetic control of their formation and maintenance, we performed a genome-wide chronological expression profile identifying the dynamic transcriptomic changes involved in establishment of muscle stem cells through life, and acquisition of muscle stem cell properties. We have identified multiple genes and pathways associated with satellite cell formation, including set of genes specifically induced (EphA1, EphA2, EfnA1, EphB1, Zbtb4, Zbtb20) or inhibited (EphA3, EphA4, EphA7, EfnA2, EfnA3, EfnA4, EfnA5, EphB2, EphB3, EphB4, EfnBs, Zfp354c, Zcchc5, Hmga2) in adult stem cells. Ephrin receptors and ephrins ligands have been implicated in cell migration and guidance in many tissues including skeletal muscle. Here we show that Ephrin receptors and ephrins ligands are also involved in regulating the adult myogenic program. Strikingly, impairment of EPHB1 function in satellite cells leads to increased differentiation at the expense of self-renewal in isolated myofiber cultures. In addition, we identified new transcription factors, including several zinc finger proteins. ZFP354C and ZCCHC5 decreased self-renewal capacity when overexpressed, whereas ZBTB4 increased it, and ZBTB20 induced myogenic progression. The architectural and transcriptional regulator HMGA2 was involved in satellite cell activation. Together, our study shows that transcriptome profiling coupled with myofiber culture analysis, provides an efficient system to identify and validate candidate genes implicated in establishment/maintenance of muscle stem cells. Furthermore, tour de force transcriptomic profiling provides a wealth of data to inform for future stem cell-based muscle therapies.

Nutrigenomics and Beef Quality: A Review about Lipogenesis

The objective of the present review is to discuss the results of published studies that show how nutrition affects the expression of genes involved in lipid metabolism and how diet manipulation might change marbling and composition of fat in beef. Several key points in the synthesis of fat in cattle take place at the molecular level, and the association of nutritional factors with the modulation of this metabolism is one of the recent targets of nutrigenomic research. Within this context, special attention has been paid to the study of nuclear receptors associated with fatty acid metabolism. Among the transcription factors involved in lipid metabolism, the peroxisome proliferator-activated receptors (PPARs) and sterol regulatory element-binding proteins (SREBPs) stand out. The mRNA synthesis of these transcription factors is regulated by nutrients, and their metabolic action might be potentiated by diet components and change lipogenesis in muscle. Among the options for dietary manipulation with the objective to modulate lipogenesis, the use of different sources of polyunsaturated fatty acids, starch concentrations, forage ratios and vitamins stand out. Therefore, special care must be exercised in feedlot feed management, mainly when the goal is to produce high marbling beef.

Comprehensive transcriptomic and proteomic characterization of human mesenchymal stem cells reveals source specific cellular markers

Mesenchymal stem cells (MSC) are multipotent cells with great potential in therapy, reflected by more than 500 MSC-based clinical trials registered with the NIH. MSC are derived from multiple tissues but require invasive harvesting and imply donor-to-donor variability. Embryonic stem cell-derived MSC (ESC-MSC) may provide an alternative, but how similar they are to ex vivo MSC is unknown. Here we performed an in depth characterization of human ESC-MSC, comparing them to human bone marrow-derived MSC (BM-MSC) as well as human embryonic stem cells (hESC) by transcriptomics (RNA-seq) and quantitative proteomics (nanoLC-MS/MS using SILAC). Data integration highlighted and validated a central role of vesicle-mediated transport and exosomes in MSC biology and also demonstrated, through enrichment analysis, their versatility and broad application potential. Particular emphasis was placed on comparing profiles between ESC-MSC and BM-MSC and assessing their equivalency. Data presented here shows that differences between ESC-MSC and BM-MSC are similar in magnitude to those reported for MSC of different origin and the former may thus represent an alternative source for therapeutic applications. Finally, we report an unprecedented coverage of MSC CD markers, as well as membrane associated proteins which may benefit immunofluorescence-based applications and contribute to a refined molecular description of MSC.

ZNF687 Mutations in Severe Paget Disease of Bone Associated with Giant Cell Tumor

Paget disease of bone (PDB) is a skeletal disorder characterized by focal abnormalities of bone remodeling, which result in enlarged and deformed bones in one or more regions of the skeleton. In some cases, the pagetic tissue undergoes neoplastic transformation, resulting in osteosarcoma and, less frequently, in giant cell tumor of bone (GCT). We performed whole-exome sequencing in a large family with 14 PDB-affected members, four of whom developed GCT at multiple pagetic skeletal sites, and we identified the c.2810C>G (p.Pro937Arg) missense mutation in the zinc finger protein 687 gene (ZNF687). The mutation precisely co-segregated with the clinical phenotype in all affected family members. The sequencing of seven unrelated individuals with GCT associated with PDB (GCT/PDB) identified the same mutation in all individuals, unravelling a founder effect. ZNF687 is highly expressed during osteoclastogenesis and osteoblastogenesis and is dramatically upregulated in the tumor tissue of individuals with GCT/PDB. Interestingly, our preliminary findings showed that ZNF687, indicated as a target gene of the NFkB transcription factor by ChIP-seq analysis, is also upregulated in the peripheral blood of PDB-affected individuals with (n = 5) or without (n = 6) mutations in SQSTM1, encouraging additional studies to investigate its potential role as a biomarker of PDB risk.

Bioresorbable zinc hydroxyapatite guided bone regeneration membrane for bone regeneration

OBJECTIVES

The aim of this study was to investigate the bone regenerative properties of a heat treated cross-linked GBR membrane with zinc hydroxyapatite powders in the rat calvarial defect model over a 6-week period.

MATERIAL AND METHODS

In vitro physio-chemical characterization involved X-ray diffraction analysis, surface topology by scanning electron microscopy, and zinc release studies in physiological buffers. Bilateral rat calvarial defects were used to compare the Zn-HAp membranes against the commercially available collagen membranes and the unfilled defect group through radiological and histological evaluation.

RESULTS

The synthesized Zn-MEM (100 μm thick) showed no zinc ions released in the phosphate buffer solution (PBS) buffer, but zinc was observed under acidic conditions. At 6 weeks, both the micro-CT and histological analyses revealed that the Zn-MEM group yielded significantly greater bone formation with 80 ± 2% of bone filled, as compared with 60 ± 5% in the collagen membrane and 40 ± 2% in the unfilled control group.

CONCLUSION

This study demonstrated the use of heat treatment as an alternative method to cross-linking the Zn-MEM to be applied as a GBR membrane. Its synthesis and production are relatively simple to fabricate, and the membrane had rough surface features on one side, which might be beneficial for cellular activities. In a rat calvarial defect model, it was shown that new bone formation was accelerated in comparison with the collagen membrane and the unfilled defect groups. These results would suggest that Zn-MEM has the potential for further development in dental applications.

Effect of zinc on liver cirrhosis with hyperammonemia: a preliminary randomized, placebo-controlled double-blind trial

OBJECTIVE

To our knowledge, no randomized study has shown whether zinc replacement therapy is effective for hyperammonemia in liver cirrhosis; therefore, we performed a double-blind, placebo-controlled trial to examine efficacy and safety of the zinc replacement therapy.

METHODS

Patients with liver cirrhosis and hyperammonemia (at or above the institutional reference value) and hypozincemia (≤65 μg/dL) were enrolled in the outpatient units of the participating institutions and were randomly divided to receive placebo (P group) or zinc acetate preparation at a dose of 3 capsules/d for a total zinc content of 150 mg/d (Z group) by the envelope method. Of the 18 enrolled patients, 6 dropped out; thus, the analyses included 12 patients (5 in the P group and 7 in the Z group). Variations in blood concentrations of zinc and ammonia as well as liver function test results were compared.

RESULTS

Blood zinc levels significantly increased in the Z group (P = 0.0037; Friedman test) but not the P group. Blood ammonia levels significantly decreased in the Z group (P = 0.0114; Friedman test) but not the P group. The percent change in blood ammonia level also revealed significant reduction at the eighth week in the Z group (P = 0.0188: Mann-Whitney test). No serious adverse events attributable to the zinc preparation were noted.

CONCLUSION

Although this study is preliminary and includes a small sample, it is, to our knowledge, the first randomized controlled trial to show that zinc supplementation for 3 mo seems effective and safe for treating hyperammonemia in liver cirrhosis. Studies with a larger sample size are needed to confirm our findings.

Dietary zinc is a key environmental modifier in the progression of IgA nephropathy

IgA nephropathy (IgAN) shows diverse epidemiological characteristics, resulting from both genetic and acquired (e.g., environmental) causes. Environmental factors, such as diet or exposure to exogenous antigens, may prescribe the progression or prognosis of IgAN. It remains unclear as to how diet and infection influence susceptibility to IgAN. A relationship, such as Toll-like receptors (TLRs), especially TLR9 and TLR4, was demonstrated between IgAN and pathogen-recognition molecules. Recently, zinc (Zn) was discovered to be involved in various immune-related diseases, affecting B, T, and dendritic cells (DCs). This study investigates the relationship between dietary Zn and IgAN development in IgAN-prone mice. Seven-week-old IgAN-prone mice were divided into low, normal, and high Zn diet groups. To assess exogenous pathogen-mediated immune responses, lipopolysaccharide (LPS) was nasally administered. The activity of IgAN was biochemically and pathologically evaluated during the disease course. We also examined in vitro IgA production in spleen cells or in combinations of cocultured B, T, and DCs under various Zn conditions with or without LPS. Dietary conditioning with Zn affected serum immunoglobulins and urinary albumin levels, and mesangial deposition of IgA and IgG. Zn deficiency is associated with IgAN progression through the activation of the TLR4/TIR-domain-containing adapter-inducing interferon-β (TRIF), but not the TLR9, in DCs. Zn supplementation prevented disease aggravation. Our findings indicate that immune conditioning with dietary Zn alters nephritogenic IgA production after mucosal infection.

Bone regeneration of rat tibial defect by zinc-tricalcium phosphate (Zn-TCP) synthesized from porous Foraminifera carbonate macrospheres

Foraminifera carbonate exoskeleton was hydrothermally converted to biocompatible and biodegradable zinc-tricalcium phosphate (Zn-TCP) as an alternative biomimetic material for bone fracture repair. Zn-TCP samples implanted in a rat tibial defect model for eight weeks were compared with unfilled defect and beta-tricalcium phosphate showing accelerated bone regeneration compared with the control groups, with statistically significant bone mineral density and bone mineral content growth. CT images of the defect showed restoration of cancellous bone in Zn-TCP and only minimal growth in control group. Histological slices reveal bone in-growth within the pores and porous chamber of the material detailing good bone-material integration with the presence of blood vessels. These results exhibit the future potential of biomimetic Zn-TCP as bone grafts for bone fracture repair.

Emerging roles of zinc finger proteins in regulating adipogenesis

Proteins containing the zinc finger domain(s) are named zinc finger proteins (ZFPs), one of the largest classes of transcription factors in eukaryotic genomes. A large number of ZFPs have been studied and many of them were found to be involved in regulating normal growth and development of cells and tissues through diverse signal transduction pathways. Recent studies revealed that a small but increasing number of ZFPs could function as key transcriptional regulators involved in adipogenesis. Due to the prevalence of obesity and metabolic disorders, the investigation of molecular regulatory mechanisms of adipocyte development must be more completely understood in order to develop novel and long-term impact strategies for ameliorating obesity. In this review, we discuss recent work that has documented that ZFPs are important functional contributors to the regulation of adipogenesis. Taken together, these data lead to the conclusion that ZFPs may become promising targets to combat human obesity.

Diuretics aggravate zinc deficiency in patients with liver cirrhosis by increasing zinc excretion in urine

AIM

Liver cirrhosis is often accompanied by zinc deficiency. The exact mechanisms underlying zinc deficiency remain unclear. This study was undertaken to clarify the influence of diuretics on blood zinc levels and zinc excretion in urine in liver cirrhosis.

METHODS

Seventy-nine outpatients with liver cirrhosis were divided into four groups: (i) patients receiving no zinc preparations or diuretics (LC group); (ii) those receiving zinc preparations only (LCZ group); (iii) those receiving diuretics only (LCD group); and (iv) those receiving both zinc preparations and diuretics (LCDZ group). Among these groups, the effects of the administrated drugs on blood zinc levels and urinary zinc excretion were analyzed.

RESULTS

Blood zinc levels were significantly lower in the LCD group (47.8 ± 10.5 μg/dL) than in the other groups (LC: 68.8 ± 17.1 μg/dL, P = 0.0056, post-hoc test; LCZ: 78.4 ± 18.1, P < 0.0001; LCDZ: 70.3 ± 21.4, P = 0.0008). The creatinine-adjusted urinary zinc excretion was significantly higher in the LCDZ group (548.1 ± 407.6 μg/mg creatinine) than in the other groups (LC, 58.5 ± 43.7; LCZ, 208.1 ± 227.8; LCD, 105.2 ± 154.4; each P < 0.0001). The fraction of urinary zinc excretion was also significantly higher in the LCDZ group (5.6 ± 2.9%) than in the other groups (LC, 0.6 ± 0.5; LCD, 1.7 ± 1.5; LCZ, 1.6 ± 1.2; each P < 0.0001).

CONCLUSION

In patients with liver cirrhosis, treatment with diuretics can increase zinc excretion by suppressing the reabsorption of zinc through renal tubules, which might lead to zinc deficiency.

Genome-wide association study in Han Chinese identifies three novel loci for human height

Human height is a complex genetic trait with high heritability but discovery efforts in Asian populations are limited. We carried out a meta-analysis of genome-wide association studies (GWAS) for height in 6,534 subjects with in silico replication of 1,881 subjects in Han Chinese. We identified three novel loci reaching the genome-wide significance threshold (P < 5 × 10(-8)), which mapped in or near ZNF638 (rs12612930, P = 2.02 × 10(-10)), MAML2 (rs11021504, P = 7.81 × 10(-9)), and C18orf12 (rs11082671, P = 1.87 × 10(-8)). We also confirmed two loci previously reported in European populations including CS (rs3816804, P = 2.63 × 10(-9)) and CYP19A1 (rs3751599, P = 4.80 × 10(-10)). In addition, we provided evidence supporting 35 SNPs identified by previous GWAS (P < 0.05). Our study provides new insights into the genetic determination of biological regulation of human height.

Long-term zinc deprivation accelerates rat vascular smooth muscle cell proliferation involving the down-regulation of JNK1/2 expression in MAPK signaling

BACKGROUND

The accelerated proliferation of vascular smooth muscle cells (VSMCs) is a contributor for atherosclerosis by thickening the vascular wall. Since zinc modulation of VSMC proliferation has not been clarified, this study investigated whether zinc affects VSMC proliferation.

METHODS AND RESULTS

Both a rat aorta origin vascular smooth muscle cell line (A7r5 VSMCs) and primary VSMCs which were collected from rat aorta (pVSMCs) were cultured with zinc (0-50 μM Zn) for short- (≤12 d) and long-term (28 d) periods under normal non-calcifying (0 or 1 mM P) or calcifying (>2 mM P) P conditions. Mouse vascular endothelial cells (MS I cells) were also cultured (under 0-50 μM Zn and 10 mM P for 20 d) to compare with VSMC cultures. While during short-term culture of VSMCs, zinc deprivation decreased cell proliferation in a zinc-concentration manner both under non-calcifying and calcifying conditions in A7r5 and pVSMCs (P < 0.05), during long-term cultures (28 d), A7r5 VSMC proliferation was inversely related to medium zinc concentration under normal physiological P conditions (regression coefficient r(2) = -0.563, P = 0.012). The anti-cell proliferative effect of zinc supplementation (>50 μM) was VSMC-specific. Long-term (35 d), low zinc treatment down-regulated JNK expression and activation, while not affecting ERK1/2 MAPK signaling in A7r5 VSMCs.

CONCLUSION

The results showed that chronic zinc deprivation accelerated VSMC proliferation, perhaps due to down-regulation of MAPK-JNK signaling, and that the anti-cell proliferative role of zinc is VSMC-specific. The findings suggested that zinc may have anti-VSMC proliferative properties in atherosclerosis.

Identification of ZNF395 as a novel modulator of adipogenesis

Adipogenesis is the process of cell differentiation by which mesenchymal stem cells (MSC) become adipocytes. Investigating the transcriptional regulatory process during adipogenesis may provide strategies to prevent obesity and other metabolic disorders. In recent years, numerous zinc finger proteins (ZFPs) have been implicated in regulating differentiation and cell fate determination. To investigate the regulatory role of ZFPs involved in adipogenesis, we performed genome-wide microarray expression profiling of an adipogenesis time series. Particularly focusing on the transiently responsive ZFPs, we identified and characterized the functional role of ZNF395 in adipogenesis. A systematic ablation of the ZNF395 transcript during adipogenesis revealed 40% reduction of adipocytes when compared to control. Furthermore, the number of adipocytes as well as the expression of key adipocyte markers were greatly induced when MSC were co-transduced with ZNF395 and PPARG2. To further elucidate the functional role of ZNF395 during adipogenesis, we attempted to trans-differentiate human dermal fibroblasts with PPARG2. The test remarkably revealed that ZNF395 in conjunction with PPARG2 greatly induced adipogenesis from dermal fibroblasts when compared to PPARG2 alone. These loss and gain of function experiments firmly establish that ZNF395 coordinate the transcriptional regulatory pathway with PPARG2, which may be necessary for the genesis of adipocytes.

Immune and inflammatory pathways are involved in inherent bone marrow ossification

BACKGROUND

Bone marrow plays a key role in bone formation and healing. Although a subset of marrow explants ossifies in vitro without excipient osteoinductive factors, some explants do not undergo ossification. The disparity of outcome suggests a significant heterogeneity in marrow tissue in terms of its capacity to undergo osteogenesis.

QUESTIONS/PURPOSES

We sought to identify: (1) proteins and signaling pathways associated with osteogenesis by contrasting the proteomes of ossified and poorly ossified marrow explants; and (2) temporal changes in proteome and signaling pathways of marrow ossification in the early and late phases of bone formation.

METHODS

Explants of marrow were cultured. Media conditioned by ossified (n = 4) and poorly ossified (n = 4) subsets were collected and proteins unique to each group were identified by proteomic analysis. Proteomic data were processed to assess proteins specific to the early phase (Days 1-14) and late phase (Days 15-28) of the culture period. Pathways involved in bone marrow ossification were identified through bioinformatics.

RESULTS

Twenty-eight proteins were unique to ossified samples and eight were unique to poorly ossified ones. Twelve proteins were expressed during the early phase and 15 proteins were specific to the late phase. Several identified pathways corroborated those reported for bone formation in the literature. Immune and inflammatory pathways were specific to ossified samples.

CONCLUSIONS

The marrow explant model indicates the inflammatory and immune pathways to be an integral part of the osteogenesis process.

Control of Differentiation of Human Mesenchymal Stem Cells by Altering the Geometry of Nanofibers

Effective differentiation of mesenchymal stem cells (MSCs) is required for clinical applications. To control MSC differentiation, induction media containing different types of soluble factors have been used to date; however, it remains challenging to obtain a uniformly differentiated population of an appropriate quality for clinical application by this approach. We attempted to develop nanofiber scaffolds for effective MSC differentiation by mimicking anisotropy of the extracellular matrix structure, to assess whether differentiation of these cells can be controlled by using geometrically different scaffolds. We evaluated MSC differentiation on aligned and random nanofibers, fabricated by electrospinning. We found that induction of MSCs into adipocytes was markedly more inhibited on random nanofibers than on aligned nanofibers. In addition, adipoinduction on aligned nanofibers was also inhibited in the presence of mixed adipoinduction and osteoinduction medium, although osteoinduction was not affected by a change in scaffold geometry. Thus, we have achieved localized control over the direction of differentiation through changes in the alignment of the scaffold even in the presence of a mixed medium. These findings indicate that precise control of MSC differentiation can be attained by using scaffolds with different geometry, rather than by the conventional use of soluble factors in the medium.

Zinc finger protein 467 is a novel regulator of osteoblast and adipocyte commitment

Osteoblasts and adipocytes are derived from common mesenchymal progenitor cells. The bone loss of osteoporosis is associated with altered progenitor differentiation from an osteoblastic to an adipocytic lineage. cDNA microarrays and quantitative real-time PCR (Q-PCR) were carried out in a differentiating mouse stromal osteoblastic cell line, Kusa 4b10, to identify gene targets of factors that stimulate osteoblast differentiation including parathyroid hormone (PTH) and gp130-binding cytokines, oncostatin M (OSM) and cardiotrophin-1 (CT-1). Zinc finger protein 467 (Zfp467) was rapidly down-regulated by PTH, OSM, and CT-1. Retroviral overexpression and RNA interference for Zfp467 in mouse stromal cells showed that this factor stimulated adipocyte formation and inhibited osteoblast commitment compared with controls. Regulation of adipocyte markers, including peroxisome proliferator-activated receptor (PPAR) γ, C/EBPα, adiponectin, and resistin, and late osteoblast/osteocyte markers (osteocalcin and sclerostin) by Zfp467 was confirmed by Q-PCR. Intra-tibial injection of calvarial cells transduced with retroviral Zfp467 doubled the number of marrow adipocytes in C57Bl/6 mice compared with vector control-transduced cells, providing in vivo confirmation of a pro-adipogenic role of Zfp467. Furthermore, Zfp467 transactivated a PPAR-response element reporter construct and recruited a histone deacetylase complex. Thus Zfp467 is a novel co-factor that promotes adipocyte differentiation and suppresses osteoblast differentiation. This has relevance to therapeutic interventions in osteoporosis, including PTH-based therapies currently available, and may be of relevance for the use of adipose-derived stem cells for tissue engineering.

Distribution and location of genetic effects for dairy traits

Genetic effects for many dairy traits and for total economic merit are evenly distributed across all chromosomes. A high-density scan using 38,416 single nucleotide polymorphism markers for 5,285 bulls confirmed 2 previously known major genes on Bos taurus autosomes (BTA) 6 and 14 but revealed few other large effects. Markers on BTA18 had the largest effects on calving ease, several conformation traits, longevity, and total merit. Prediction accuracy was highest using a heavy-tailed prior assuming that each marker had an effect on each trait, rather than assuming a normal distribution of effects as in a linear model, or that only some loci have nonzero effects. A prior model combining heavy tails with finite alleles produced results that were intermediate compared with the individual models. Differences between models were small (1 to 2%) for traits with no major genes and larger for heavy tails with traits having known quantitative trait loci (QTL; 6 to 8%). Analysis of bull recessive codes suggested that marker effects from genomic selection may be used to identify regions of chromosomes to search in detail for candidate genes, but individual single nucleotide polymorphisms were not tracking causative mutations with the exception of diacylglycerol O-acyltransferase 1. Additive genetic merits were constructed for each chromosome, and the distribution of BTA14-specific estimated breeding value (EBV) showed that selection primarily for milk yield has not changed the distribution of EBV for fat percentage even in the presence of a known QTL. Such chromosomal EBV also may be useful for identifying complementary mates in breeding programs. The QTL affecting dystocia, conformation, and economic merit on BTA18 appear to be related to calf size or birth weight and may be the result of longer gestation lengths. Results validate quantitative genetic assumptions that most traits are due to the contributions of a large number of genes of small additive effect, rather than support the finite locus model.

Sp proteins and Runx2 mediate regulation of matrix gla protein (MGP) expression by parathyroid hormone

As part of its catabolic action in bone, parathyroid hormone (PTH) inhibits extracellular matrix mineralization. We previously showed that PTH dose-dependently induces matrix gla protein (MGP) expression in osteoblasts and this induction is at least partially responsible for PTH-mediated inhibition of mineralization. Recently, we identified PKA and ERK/MAPK as the key signaling pathways involved in PTH regulation of MGP expression. The goal of this study was to further characterize the mechanism by which PTH stimulates expression of MGP. Deletion analysis of the murine Mgp gene promoter identified a PTH-responsive region between -173 bp and-49 bp. Using gel-mobility shift assays we found that Sp1/Sp3, and Runx2 bind to distinct sites within this region. Mutation of either the Sp or the Runx2 site reduced MGP induction by PTH, while mutation of both sites completely abolished PTH responsiveness. Overexpression of Runx2 or Sp1 activated the Mgp reporter, while Sp3 was a dose-dependent repressor of Sp1 and PTH-induced MGP expression. Collectively, these data show that PTH regulates MGP gene transcription in osteoblasts through altered activities of Sp and Runx2 transcription factors.

GhZFP1, a novel CCCH-type zinc finger protein from cotton, enhances salt stress tolerance and fungal disease resistance in transgenic tobacco by interacting with GZIRD21A and GZIPR5

* Zinc finger proteins are a superfamily involved in many aspects of plant growth and development. However, CCCH-type zinc finger proteins involved in plant stress tolerance are poorly understood. * A cDNA clone designated Gossypium hirsutum zinc finger protein 1 (GhZFP1), which encodes a novel CCCH-type zinc finger protein, was isolated from a salt-induced cotton (G. hirsutum) cDNA library using differential hybridization screening and further studied in transgenic tobacco Nicotiana tabacum cv. NC89. Using yeast two-hybrid screening (Y2H), proteins GZIRD21A (GhZFP1 interacting and responsive to dehydration protein 21A) and GZIPR5 (GhZFP1 interacting and pathogenesis-related protein 5), which interacted with GhZFP1, were isolated. * GhZFP1 contains two typical zinc finger motifs (Cx8Cx5Cx3H and Cx5Cx4Cx3H), a putative nuclear export sequence (NES) and a potential nuclear localization signal (NLS). Transient expression analysis using a GhZFP1::GFP fusion gene in onion epidermal cells indicated a nuclear localization for GhZFP1. RNA blot analysis showed that the GhZFP1 transcript was induced by salt (NaCl), drought and salicylic acid (SA). The regions in GhZFP1 that interact with GZIRD21A and GZIPR5 were identified using truncation mutations. * Overexpression of GhZFP1 in transgenic tobacco enhanced tolerance to salt stress and resistance to Rhizoctonia solani. Therefore, it appears that GhZFP1 might be involved as an important regulator in plant responses to abiotic and biotic stresses.

Genome-wide association scan for stature in Chinese: evidence for ethnic specific loci

In Caucasian, several studies have identified some common variants associated with human stature variation. However, no such study was performed in Chinese, which is the largest population in the world and evidently differs from Caucasian in genetic background. To identify common or ethnic specific genes for stature in Chinese, an initial GWAS and follow-up replication study were performed. Our initial GWAS study found that a group of 13 contiguous SNPs, which span a region of approximately 150 kb containing two neighboring genes, zinc finger protein (ZNP) 510 and ZNP782, achieved strong signals for association with stature, with P values ranging from 9.71 x 10(-5) to 3.11 x 10(-6). After false discovery rate correction for multiple testing, 9 of the 13 SNPs remain significant (FDR q=0.036-0.046). The follow-up replication study in an independent 2,953 unrelated southern Chinese confirmed the association of rs10816533 with stature (P=0.029). All the 13 SNPs were in consistently strong linkage disequilibrium (D'>0.99) and formed a single perfect haplotype block. The minor allele frequencies for the 13 contiguous SNPs have evidently ethnic difference, which range from 0.21 to 0.33 in Chinese but have as low as approximately 0.017 reported in dbSNP database in Caucasian. The present results suggest that the genomic region containing the ZNP510 and ZNP782 genes is an ethnic specific locus associated with stature variation in Chinese.

Transcription factors CTCF and Pax6 are segregated to different cell types during retinal cell differentiation

We have hypothesized that the transcription factor CTCF may influence retinal cell differentiation by controlling Pax6 expression, because (1) CTCF has been shown to repress Pax6 expression in some tissues, and (2) Pax6 blocks the differentiation of retinal progenitor cells as photoreceptors and promotes their differentiation as nonphotoreceptor neurons. Our results show that, as predicted by this hypothesis, CTCF and Pax6 become segregated to different retinal cell types. The factors are initially coexpressed in the undifferentiated neuroepithelium, but already at that time they show complementary periphery-to-fundus gradients of distribution. As the retina laminates, Pax6 becomes restricted to ganglion and amacrine cells, and CTCF to the bipolar/Muller cell layer and the outer nuclear layer. Polymerase chain reaction analysis of laser capture microdissection samples and dissociated cells showed that both immature and differentiated photoreceptors are CTCF (+)/ Pax6 (-). Functional studies are now under way to further analyze the role of CTCF in retinal cell differentiation.

ZNF307, a novel zinc finger gene suppresses p53 and p21 pathway

We have cloned a novel KRAB-related zinc finger gene, ZNF307, encoding a protein of 545aa. ZNF307 is conserved across species in evolution and is differentially expressed in human adult and fetal tissues. The fusion protein of EGFP-ZNF307 localizes in the nucleus. Transcriptional activity assays show ZNF307 suppresses transcriptional activity of L8G5-luciferase. Overexpressing ZNF307 in different cell lines also inhibits the transcriptional activities of p53 and p21. Moreover, ZNF307 works by reducing the p53 protein level and p53 protein reduction is achieved by increasing transcription of MDM2 and EP300. ZNF307 might suppress p53-p21 pathway through activating MDM2 and EP300 expression and inducing p53 degradation.

Zinc and the liver: an active interaction

Zinc is an essential trace element, exerting important antioxidant, anti-inflammatory, and antiapoptotic effects. It affects growth and development and participates in processes such as aging and cancer induction. The liver is important for the regulation of zinc homeostasis, while zinc is necessary for proper liver function. Decreased zinc levels have been implicated in both acute and chronic liver disease states, and zinc deficiency has been implicated in the pathogenesis of liver diseases. Zinc supplementation offers protection in experimental animal models of acute and chronic liver injury, but these hepatoprotective properties have not been fully elucidated. In the present review, data on zinc homeostasis, its implication in the pathogenesis of liver diseases, and its effect on acute and chronic liver diseases are presented. It is concluded that zinc could protect against liver diseases, although up to now the underlying pathophysiology of zinc and liver interactions have not been defined.

Enamel matrix derivative stimulates chondrogenic differentiation of ATDC5 cells

BACKGROUND AND OBJECTIVES

Although enamel matrix derivative can promote chondrogenic differentiation of pluripotent mesenchymal precursor cells, the molecular mechanism that underlies this phenomenon is unclear. The purpose of this study was to determine the effect of enamel matrix derivative on chondrogenic differentiation. ATDC5 cells, which undergo a reproducible multistep chondrogenic differentiation, were cultured with or without enamel matrix derivative for up to 35 d.

METHODS AND RESULTS

Cell proliferation and alkaline phosphatase activity increased markedly in cells cultured in the presence of enamel matrix derivative, compared with cells cultured in its absence. Deposition of Alcian blue-positive cartilage matrix and Alizarin red-positive mineralized nodules also increased significantly upon treatment with enamel matrix derivative. Expression of mRNAs encoding cartilage extracellular matrix proteins (type II collagen, type X collagen and aggrecan) and chondrogenic-related transcription factors (Sox9, Zfp60 and AJ18) were measured using the real-time polymerase chain reaction. Type II collagen, type X collagen and aggrecan mRNA expression increased markedly with enamel matrix derivative treatment. Transcription of Sox9, an important transcription factor that mediates chondrogenic differentiation, also increased with enamel matrix derivative treatment. The KRAB/C2H2 zinc-finger transcription factors, Zfp60 and AJ18, were transiently expressed in the prehypertrophic stage, and their expression increased with enamel matrix derivative treatment. In a western blot analysis with anti-insulin-like growth factor-I and anti-bone morphogenetic protein-6 immunoglobulin, bands corresponding to approximately 14, approximately 18 and approximately 60 kDa were found in enamel matrix derivative.

CONCLUSION

Our study provides clear evidence that enamel matrix derivative promotes chondrogenic differentiation of ATDC5 cells.

Transcriptional control of lung morphogenesis

The vertebrate lung consists of multiple cell types that are derived primarily from endodermal and mesodermal compartments of the early embryo. The process of pulmonary organogenesis requires the generation of precise signaling centers that are linked to transcriptional programs that, in turn, regulate cell numbers, differentiation, and behavior, as branching morphogenesis and alveolarization proceed. This review summarizes knowledge regarding the expression and proposed roles of transcription factors influencing lung formation and function with particular focus on knowledge derived from the study of the mouse. A group of transcription factors active in the endodermally derived cells of the developing lung tubules, including thyroid transcription factor-1 (TTF-1), beta-catenin, Forkhead orthologs (FOX), GATA, SOX, and ETS family members are required for normal lung morphogenesis and function. In contrast, a group of distinct proteins, including FOXF1, POD1, GLI, and HOX family members, play important roles in the developing lung mesenchyme, from which pulmonary vessels and bronchial smooth muscle develop. Lung formation is dependent on reciprocal signaling among cells of both endodermal and mesenchymal compartments that instruct transcriptional processes mediating lung formation and adaptation to breathing after birth.