Reciprocal negative feedback between Prrx1 and miR-140-3p regulates rapid chondrogenesis in the regenerating antler

During growth phase, antlers exhibit a very rapid rate of chondrogenesis. The antler is formed from its growth center reserve mesenchyme (RM) cells, which have been found to be the derivatives of paired related homeobox 1 (Prrx1)-positive periosteal cells. However, the underlying mechanism that drives rapid chondrogenesis is not known. Herein, the miRNA expression profiles and chromatin states of three tissue layers (RM, precartilage, and cartilage) at different stages of differentiation within the antler growth center were analyzed by RNA-sequencing and ATAC-sequencing. We found that miR-140-3p was the miRNA that exhibited the greatest degree of upregulation in the rapidly growing antler, increasing from the RM to the cartilage layer. We also showed that Prrx1 was a key upstream regulator of miR-140-3p, which firmly confirmed by Prrx1 CUT&Tag sequencing of RM cells. Through multiple approaches (three-dimensional chondrogenic culture and xenogeneic antler model), we demonstrated that Prrx1 and miR-140-3p functioned as reciprocal negative feedback in the antler growth center, and downregulating PRRX1/upregulating miR-140-3p promoted rapid chondrogenesis of RM cells and xenogeneic antler. Thus, we conclude that the reciprocal negative feedback between Prrx1 and miR-140-3p is essential for balancing mesenchymal proliferation and chondrogenic differentiation in the regenerating antler. We further propose that the mechanism underlying chondrogenesis in the regenerating antler would provide a reference for helping understand the regulation of human cartilage regeneration and repair.

The Genetic Diversity of Mink (Neovison vison) Populations in China

The American mink (Neovison vison) is a semiaquatic species of Mustelid native to North America that is now widespread in China. However, the knowledge of genetic diversity of mink in China is still limited. In this study, we investigated the genetic diversity and identified significant single nucleotide polymorphisms (SNPs) in mink populations of five different color types in three different mink farms in China. Using double-digest restriction site-associated DNA sequencing, we identified a total of 1.3 million SNPs. After filtering the SNPs, phylogenetic tree, Fst, principal component, and population structure analyses were performed. The results demonstrated that red mink and black mink grouped, with separate clustering of all other color types. The population divergence index (Fst) study confirmed that different mink populations were distinct (K = 4). Two populations with different coat colors were subjected to the selection signature analysis, and 2300 genes were found to have a clear selection signature. The genes with a selection signature were subjected to Gene Ontology (GO) categorization and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, the results revealed that the genes with a selection signature were enriched in the melanogenesis pathway. These study's findings have set the stage for improved breeding and conservation of genetic resources in real-world practical mink farming.

A population of stem cells with strong regenerative potential discovered in deer antlers

The annual regrowth of deer antlers provides a valuable model for studying organ regeneration in mammals. We describe a single-cell atlas of antler regrowth. The earliest-stage antler initiators were mesenchymal cells that express the paired related homeobox 1 gene (PRRX1⁺ mesenchymal cells). We also identified a population of "antler blastema progenitor cells" (ABPCs) that developed from the PRRX1⁺ mesenchymal cells and directed the antler regeneration process. Cross-species comparisons identified ABPCs in several mammalian blastema. In vivo and in vitro ABPCs displayed strong self-renewal ability and could generate osteochondral lineage cells. Last, we observed a spatially well-structured pattern of cellular and gene expression in antler growth center during the peak growth stage, revealing the cellular mechanisms involved in rapid antler elongation.

Single-cell transcriptome reveals core cell populations and androgen-RXFP2 axis involved in deer antler full regeneration

Deer antlers constitute a unique mammalian model for the study of both organ formation in postnatal life and annual full regeneration. Previous studies revealed that these events are achieved through the proliferation and differentiation of antlerogenic periosteum (AP) cells and pedicle periosteum (PP) cells, respectively. As the cells resident in the AP and the PP possess stem cell attributes, both antler generation and regeneration are stem cell-based processes. However, the cell composition of each tissue type and molecular events underlying antler development remain poorly characterized. Here, we took the approach of single-cell RNA sequencing (scRNA-Seq) and identified eight cell types (mainly THY1⁺ cells, progenitor cells, and osteochondroblasts) and three core subclusters of the THY1⁺ cells (SC2, SC3, and SC4). Endothelial and mural cells each are heterogeneous at transcriptional level. It was the proliferation of progenitor, mural, and endothelial cells in the activated antler-lineage-specific tissues that drove the rapid formation of the antler. We detected the differences in the initial differentiation process between antler generation and regeneration using pseudotime trajectory analysis. These may be due to the difference in the degree of stemness of the AP-THY1⁺ and PP-THY1⁺ cells. We further found that androgen-RXFP2 axis may be involved in triggering initial antler full regeneration. Fully deciphering the cell composition for these antler tissue types will open up new avenues for elucidating the mechanism underlying antler full renewal in specific and regenerative medicine in general.

Calreticulin Identified as One of the Androgen Response Genes That Trigger Full Regeneration of the Only Capable Mammalian Organ, the Deer Antler

Deer antlers are male secondary sexual characters that develop to become bone; they are unique appendages that, once lost, can fully regenerate from the permanent bony protuberances or pedicles. Pedicle periosteum (PP) is the tissue that gives rise to the regenerating antlers with three differentiation stages, namely, dormant (DoPP), potentiated (PoPP), and activated (AcPP). Thus far, the transition from the PoPP to the AcPP has not been studied. Our results showed that the AcPP cells maintained their original stem cell features by expressing mesenchymal stem cell (MSC) markers CD73, CD90, and CD105, although they had entered the proliferation mode. The differentially expressed genes (DEGs) in the AcPP compared with those of the PoPP were mainly involved in protein processing, cell cycle, and calcium signaling pathways. Calreticulin (CALR), an androgen response gene, was significantly differentially upregulated in the AcPP cells, and its expression level was negatively regulated by androgens, in contrast to the currently known model systems where all regulation is positive. The downregulation of CALR expression in the AcPP cells in vitro inhibited cell proliferation, induced apoptosis, and inhibited cell cycle progression at G1-S transition. Therefore, CALR is likely a downstream mediator of androgen hormones for triggering initiation of antler regeneration. We believe that the identification of CALR has not only discovered “one critical piece” of the “jigsaw puzzle” in the initiation of antler regeneration but also helps in revealing the mechanism underlying this unique mammalian epimorphic regeneration and has also opened a new avenue for the study of the nature of CALR regulation by androgen (putative binding partners), thus facilitating the identification of potential molecule(s) for investigation as targets for clinical evaluation.

Cross-Species Analysis Reveals Co-Expressed Genes Regulating Antler Development in Cervidae

Antlers constitute an interesting model for basic research in regenerative biology. Despite decades of being studied, much is still unknown about the genes related to antler development. Here, we utilized both the genome and antlerogenic periosteum (AP) transcriptome data of four deer species to reveal antler-related genes through cross-species comparative analysis. The results showed that the global gene expression pattern matches the status of antler phenotypes, supporting the fact that the genes expressed in the AP may be related to antler phenotypes. The upregulated genes of the AP in three-antlered deer showed evidence of co-expression, and their protein sequences were highly conserved. These genes were growth related and likely participated in antler development. In contrast, the upregulated genes in antler-less deer (Chinese water deer) were involved mainly in organismal death and growth failure, possibly related to the loss of antlers during evolution. Overall, this study demonstrates that the co-expressed genes in antlered deer may regulate antler development.

Long-term prognosis of patients with permanent cardiac pacemaker indication in three referral cardiac centers in Cameroon: Insights from the National pacemaker registry

BACKGROUND

There is evidence that cardiac pacemakers improve symptoms and quality of life in patients with severe bradycardia. Globally, the number of pacemaker implantations is on the rise. However, the associated high-cost limits pacemaker's accessibility in low resource settings. This study aimed to investigate access to pacemakers and the long-term outcome of patients requiring a pacemaker.

METHOD

We conducted a cohort study in 03 health care structures in Cameroon. Participants aged at least 18 years with indication for a permanent pacemaker between January 2010 and May 2016 were included. Clinical profile, electrocardiography, pacemaker implantation parameters were recorded. Long-term survival was studied by event-free analysis using the Kaplan-Meier method.

RESULTS

In total, 147 participants (mean age 67.7±13.7 years, female 58.5%) were included. Fatigue (78.7%), dyspnoea (77.2%), dizziness (47.1%) and palpitations (40.4%) were the main symptoms while syncope was present in 35.7% of patients. The main indication for cardiac pacemaker was atrioventricular block (85.3%). Forty (27.2%) could not be implanted with 34 (85%) of participants highlighting cost of intervention as main reason. VVIR was the main mode of stimulation (70.5%). Of 125 patients in which follow-up was ascertained, 17(13.5%) died after a median survival time of 2.8 years post diagnosis [IQR: 1.8-4.2]. The survival curve was better in participants with a pacemaker with a Hazard ratio of 2.7 [CI: 1.0-7.3, P=0.045].

CONCLUSION

Our patients with severe heart blocks presented late and more than a quarter did not have access to pacemaker but its implantation multiplied the survival rate by 2.7 times at approximately 3 years post diagnosis. Improving early detection of heart blocks and access to cardiac pacing to reduce mortality shall be a key future priority.

Chromosome-level genome assembly of Tarim red deer, Cervus elaphus yarkandensis

Tarim red deer (Cervus elaphus yarkandensis) is the only subspecies of red deer (of 22 subspecies) from Central Asia. This species is a desert dweller of the Tarim Basin of southern Xinjiang, China, and exhibits some unique adaptations to the dry and extreme hot climate. We report here the assembly of a Tarim red deer genome employing a 10X Genomics library, termed CEY_v1. Our genome consisted of 2.6 Gb with contig N50 and scaffold N50 of 275.5 Kb and 31.7 Mb, respectively. Around 96% of the assembled sequences were anchored onto 34 chromosomes based on the published high-quality red deer genetic linkage map. More than 94% BUSCOs complete genes (including 90.5% single and 3.6% duplicated ones) were detected in the CEY_v1 and 20,653 genes were annotated. The CEY_v1 is expected to contribute to comparative analysis of genome biology, to evolutionary studies within Cervidae, and to facilitating investigation of mechanisms underlying adaptation of this species to the extreme dry and hot climate.

Measurement(s)	DNA • genome • sequence_assembly • sequence feature annotation
Technology Type(s)	DNA sequencing • sequence assembly process • sequence annotation
Sample Characteristic - Organism	Cervus elaphus

Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.12410564

Molecular evidence for adaptive evolution of olfactory-related genes in cervids

BACKGROUND

Cervids have evolved very successful means for survival and thriving to adapt to various climates and environments. One of these successful means might be the effective and efficient way of communication. To support this notion, cervids are well equipped with a variety of skin glands that distribute in different body regions. However, studies relevant to adaptive evolution in cervids, particularly on olfactory reception at the molecular level, have thus far not been reported.

OBJECTIVE

To provide valuable insights into molecular evidence for the adaptive evolution of olfactory-related gene in cervids.

METHODS

Based on recently sequenced genomes of cervids and closely-related-species, we performed comparative genomic analysis at genome level using bioinformatics tools.

RESULTS

Tree topology strongly supported that Bovidae was the sister group of Moschidae and both formed a branch that was then clustered with Cervidae. Expansion of heavy chain genes of the dynein family and 51 rapidly evolving genes could be associated with adaptation of cilia that serve as sensory organelles and act as cellular antennae. Based on the branch-site model test along the deer branch spanning 7-21 mammalian species, 14 deer olfactory receptor genes were found to be undergoing positive selection pressure and 89 positive selection sites (probability > 60%) had amino acid substitutions unique to deer.

CONCLUSION

This study, for the first time, provides significant molecular evidence for adaption of olfactory-related genes of cervids according to their olfactory behavior.

Effects of macrophage-conditioned medium on sika deer (Cervus nippon) antler stem cells

Context Immune system has been claimed as the ‘main switch’ of tissue or organ regeneration. Among immune cells, macrophages stand out as important modulators in mutiple regeneration models, such as planarian, axolotl, mammalian hair and liver. As a unique model for mammals, deer antler is considered to ideal for studying complete mammalian organ regeneration. Studies have found that antler regeneration is a stem cell-based process and antler stem cells locate in the pedicle periosteum (PP). Although the regulatory roles of the immune system in other regeneration models have been extensively studied, they remain unstudied in antler regeneration. Aims To explore the possible role of macrophages in the PP cells (PPCs). Methods We treated PPCs with a macrophage-conditioned medium (MCM) and detected effects of MCM on proliferation, migration and apoptosis of the PPCs, and identified differentially expressed genes by using the RNA-seq technique. Key results We found that MCM enhanced proliferation rate and migration rate significantly and stimulated apoptosis of the PPCs. Using the RNA-seq technique, we identified 112 differentially expressed genes in the PPCs (38 downregulated and 74 upregulated) after the MCM treatment. Furthermore, gene-ontology annotation analyses showed that the upregulated genes were mainly involved in cell adhesion, chemotaxis, wound healing, growth factor-stimulated responses, and bone formation, and the downregulated genes were involved in regulation of biosynthesis. Conclusions MCM had a great influence on the antler stem cells, and macrophages might regulate antler regeneration through altering the microenvironment and gene-expression profiles of the PPCs. Implications We believe that the results of the present study would facilitate the discovery of the roles of immune system in antler stem cells and, thus, mammalian organ regeneration in general.

Reclassification of velvet antler portions following transcriptomic analysis

Context Commercially, velvet antlers along the longitudinal axis are divided into four portions, namely, wax-like (WL), blood-colour (BC), honeycomb-like (HL) and bone (B) slices from the top to the base. However, there is no evidence at a molecular level showing the accuracy of this classification. Aims The aim of the present study was to take transcriptional approach to assess the accuracy of the traditional classification for these four portions of velvet antler, and to link the expressed mRNAs of each portion with possible functions by using bioinformatics analysis. Methods Three sticks of three-branched velvet antlers of sika deer were harvested from three anaesthetised 4-year-old sika deer. On the basis of the traditional methods used commercially, the velvet antler sticks were divided into the four portions of WL, BC, HL and B. Transcriptome sequencing was performed using Illumina HiSeq × Ten at BGI (Shenzheng, China). Key results In total, 5647 genes were obtained from the four portions. Spearman correlation analysis grouped these four portions into three clusters (WL, BC, HL+B). C-means analysis further confirmed a similar trend, indicating the accuracy of the new classification based on transcriptome analysis. Further functional analysis showed that highly expressed genes in WL, BC and HL+B were mainly related to cell cycle, cartilage development, and bone development respectively. Conclusions Four-portion classification based on traditional methods should be replaced by three-portion classification based on the mRNA expression levels. Implications We believe that this new classification can contribute to velvet antler industry, providing more accuracy in the use of velvet antlers as pharmaceuticals.

Identification of proteins that mediate the role of androgens in antler regeneration using label free proteomics in sika deer (Cervus nippon)

Deer antlers offer a unique model to study organ regeneration in mammals. Antler regeneration relies on the pedicle periosteum (PP) cells and is triggered by a decrease in circulating testosterone (T). The molecular mechanism for antler regeneration is however, unclear. Label-free liquid chromatography-mass spectrometry (LC-MS/MS) was used to identify differentially-expressed proteins (DEPs) in the regeneration-potentiated PP (under low T environment) over the non-regeneration-potentiated PP (under high T environment). Out of total 273 DEPs, 189 were significantly up-regulated and 84 were down-regulated from these comparisons: after castration vs before castration, natural T vs before castration, and exogenous T vs before castration. We focused on the analysis only of those DEPs that were present in fully permissive environment to antler regeneration (low T). Nine transduction pathways were identified through the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, including the estrogen signaling pathway. A total of 639 gene ontology terms were found to be significantly enriched in regeneration-potentiated PP (low T) from the DEPs. Reliability of the label free LC-MS/MS was determined by qRT-PCR to estimate the expression level of selected genes. The results suggest that up-regulated heat shock proteins (HSP90AB1, HSP90B1), peptidyl-prolyl cis-trans isomerase 4 (FKBP4), mitogen-activated protein kinase 3 (MAPK3) and calreticulin (CALR) and down-regulated SHC-transforming protein 1 (SHC1), heat shock protein family A member 1A (HSPA1A) and proto-oncogene tyrosine-protein kinase (SRC) may be associated directly or indirectly with antler regeneration. Further studies are required to investigate the roles of these proteins in regeneration using appropriate in vivo models.

S100A4: a novel partner for heat shock protein 47 in antler stem cells and insight into the calcium ion-induced conformational changes

S100A4 is a multiple-function protein highly expressed in tumor or stem cells. We found S100A4 was a novel protein partner for heat shock protein 47 (HSP47) in deer antlerogenic periosteum cells (AP cells), indicating that S100A4 could bind with HSP47. S100A4 had both calcium-dependent and calcium-independent patterns (labeled as SCd and SCi, respectively) to execute different biological activities. Homology models of HSP47, SCd and SCi were constructed. HSP47:collagen model, HSP47:collagen I-V, HSP47:SCd and HSP47:SCi complexes were built using ZDOCK software. Together with free SCd and SCi, 200 ns molecular dynamic (MD) simulations were performed to analyze binding free energies and SCi/SCd conformational changes. The energetic results showed that SCi had the strongest affinity to HSP47, and followed by collagens. SCd had little interaction with HSP47. Decomposition energy results showed that collagen model interacted with HSP47 mainly though neutral amino acids. When SCi bound with HSP47, the majority of mediated amino acids were charged. These results indicated that SCi could compete with collagen on the binding site of HSP47. Root mean square fluctuation (RMSF) values and cross-correlation matrices of principal component analysis (PCA) were calculated to evaluate the SCi/SCd structural variation during MD simulation. Both HSP47 and Ca²⁺ could stabilize the conformation of SCi/SCd. The loops interacting with Ca²⁺s and linking the two EF-hand motifs were impacted particularly. The relative moving directions of α-helices in EF-hands were distinct by the binding effect of HSP47 and Ca²⁺. We found that SCi may regulate the differentiation of AP cells by disturbing the interaction between HSP47 and collagen. Communicated by Ramaswamy H. Sarma.

Deer antler stem cells are a novel type of cells that sustain full regeneration of a mammalian organ-deer antler

Deer antlers are extraordinary mammalian organs that can fully regenerate annually. Antler renewal is a stem cell-based epimorphic process and antler stem (AS) cells can initiate de novo generation of antlers in postnatal mammals. However, although being called stem cells, the AS cells have not been characterized at molecular level based on the stem cell criteria. Comprehensive characterization of the AS cells would undoubtedly help to decipher the mechanism underlying the full regeneration of deer antlers, the only case of stem cell-based epimorphic regeneration in mammals. In the present study, three types of AS cells (antlerogenic periosteal cells APCs, for initial pedicle and first antler formation; pedicle periosteal cells PPC, for annual antler regeneration; and reserve mesenchyme cells RMCs, for rapid antler growth), were isolated for comprehensive molecular characterization. A horn-growth-related gene, RXFP2, was found to be expressed only in AS cells lineages but not in the facial periosteal cells (FPCs, locates geographically in the vicinity of the APCs or PPCs), suggesting the RXFP2 might be a specific marker for the AS cell lineage in deer. Our results demonstrated that AS cells expressed classic MSC markers including surface markers CD73, CD90, CD105 and Stro-1. They also expressed some of the markers including Tert, Nestin, S100A4, nucleostemin and C-Myc, suggesting that they have some attributes of the ESCs. Microinjection of male APC into deer blastocysts resulted in one female foetus (110 days gestation) recovered with obvious pedicle primordia with both male and female genotype detected in the ovary. In conclusion, the AS cells should be defined as MSCs but with partial attributes of ESCs.

Transcriptomic analysis of different tissue layers in antler growth Center in Sika Deer (Cervus nippon)

BACKGROUND

With the unprecedented rapid growth rate (up to 2.75 cm/day), velvet antler is an invaluable model for the identification of potent growth factors and signaling networks for extremely fast growing tissues, mainly cartilage. Antler growth center (AGC) locates in its tip and consists of five tissue layers: reserve mesenchyme (RM), precartilage (PC), transition zone (TZ), cartilage (CA) and mineralized cartilage (MC). The aim of this study was to investigate the transcription dynamics in the AGC using RNA-seq technology.

RESULTS

Five tissue layers in the AGC were collected from three 3-year-old male sika deer using our previously reported sampling method (morphologically distinguishable). After sequencing (15 samples; triplicates/tissue layer), we assembled a reference transcriptome de novo and used RNA-seq to measure gene expression profiles across these five layers. Nine differentially expressed genes (DEGs) were selected from our data and subsequently verified using qRT-PCR. The results showed a high consistency with the RNA-seq results (R² = 0.80). Nine modules were constructed based on co-expression network analysis, and these modules contained 370 hub genes. These genes were found to be mainly involved in mesenchymal progenitor cell proliferation, chondrogenesis, osteogenesis and angiogenesis. Combination of our own results with the previously published reports, we found that Wnt signaling likely plays a key role not only in stimulating the antler stem cells or their immediate progeny, but also in promoting chondrogenesis and osteogenesis during antler development.

CONCLUSION

We have successfully assembled a reference transcriptome, generated gene expression profiling across the five tissue layers in the AGC, and identified nine co-expressed modules that contain 370 hub genes and genes predorminantly expressed in and highly relevant to each tissue layer. We believe our findings have laid the foundation for the identification of novel genes for rapid proliferation and chondrogenic differentiation of antler cells.

Proteomic Analysis of Plasma Membrane Proteins of Antler Stem Cells Using Label-Free LC⁻MS/MS

Deer antlers are unusual mammalian organs that can fully regenerate after annual shedding. Stem cells resident in the pedicle periosteum (PPCs) provide the main cell source for antler regeneration. Central to various cellular processes are plasma membrane proteins, but the expression of these proteins has not been well documented in antler regeneration. In the present study, plasma membrane proteins of PPCs and facial periosteal cells (FPCs) were analyzed using label-free liquid chromatography⁻mass spetrometry (LC⁻MS/MS). A total of 1739 proteins were identified. Of these proteins, 53 were found solely in the PPCs, 100 solely in the FPCs, and 1576 co-existed in both PPCs and FPCs; and 39 were significantly up-regulated in PPCs and 49 up-regulated in FPCs. In total, 226 gene ontology (GO) terms were significantly enriched from the differentially expressed proteins (DEPs). Five clusters of biological processes from these GO terms comprised responses to external stimuli, signal transduction, membrane transport, regulation of tissue regeneration, and protein modification processes. Further studies are required to demonstrate the relevancy of these DEPs in antler stem cell biology and antler regeneration.

Development of Diagnostic SNP Markers To Monitor Hybridization Between Sika Deer (Cervus nippon) and Wapiti (Cervus elaphus)

Sika deer (Cervus Nippon) and wapiti (Cervus elaphus) are closely related species and their hybridization can result in significant allele-shift of their gene pool. Additive genetic effects and putative heterotic effects of their hybridization on growth performance could confer considerable economic advantage in deer farming. Here, we used double-digest restriction site-associated DNA sequencing technology (ddRAD-seq) and detected ∼320,000 genome-wide SNPs from 30 captive individuals: 7 sika deer, 6 wapiti and 17 F1 hybrids (reciprocal cross). By screening observed heterozygosity of each SNP across four taxonomic groups, we report for the first time a resource of 2,015 putative diagnostic SNP markers (species-specific SNPs for sika deer and wapiti), which can be used to design tools for assessing or monitoring the degree of hybridization between sika deer and wapiti. These ddRAD-seq data and SNP datasets are also valuable resources for genome-wide studies, including trait discovery for breeders of domestic deer.

Draft genome of the reindeer (Rangifer tarandus)

Background

The reindeer (Rangifer tarandus) is the only fully domesticated species in the Cervidae family, and it is the only cervid with a circumpolar distribution. Unlike all other cervids, female reindeer, as well as males, regularly grow cranial appendages (antlers, the defining characteristics of cervids). Moreover, reindeer milk contains more protein and less lactose than bovids' milk. A high-quality reference genome of this species will assist efforts to elucidate these and other important features in the reindeer.

Findings

We obtained 615 Gb (Gigabase) of usable sequences by filtering the low-quality reads of the raw data generated from the Illumina Hiseq 4000 platform, and a 2.64-Gb final assembly, representing 95.7% of the estimated genome (2.76 Gb according to k-mer analysis), including 92.6% of expected genes according to BUSCO analysis. The contig N50 and scaffold N50 sizes were 89.7 kilo base (kb) and 0.94 mega base (Mb), respectively. We annotated 21 555 protein-coding genes and 1.07 Gb of repetitive sequences by de novo and homology-based prediction. Homology-based searches detected 159 rRNA, 547 miRNA, 1339 snRNA, and 863 tRNA sequences in the genome of R. tarandus. The divergence time between R. tarandus and ancestors of Bos taurus and Capra hircus is estimated to be about 29.5 million years ago.

Conclusions

Our results provide the first high-quality reference genome for the reindeer and a valuable resource for studying the evolution, domestication, and other unusual characteristics of the reindeer.

Pyridine-decorated carbon nanotubes as a metal-free heterogeneous catalyst for mild CO2 reduction to methanol with hydroboranes

Pyridine decorated multi-walled carbon nanotubes have been employed as heterogeneous metal-free catalysts for CO₂ hydroboration to methyl borinate under mild conditions. Mechanistic insights have unveiled the non-innocent role of the nanotube carrier in the catalytic performance.

Serum Uric Acid Is Associated with Poor Outcome in Black Africans in the Acute Phase of Stroke

BACKGROUND

Prognostic significance of serum uric acid (SUA) in acute stroke still remains controversial.

OBJECTIVES

To determine the prevalence of hyperuricemia and its association with outcome of stroke patients in the Douala General Hospital (DGH).

METHODS

This was a hospital based prospective cohort study which included acute stroke patients with baseline SUA levels and 3-month poststroke follow-up data. Associations between high SUA levels and stroke outcomes were analyzed using multiple logistic regression and survival analysis (Cox regression and Kaplan-Meier).

RESULTS

A total of 701 acute stroke patients were included and the prevalence of hyperuricemia was 46.6% with a mean SUA level of 68.625 ± 24 mg/l. Elevated SUA after stroke was associated with death (OR = 2.067; 95% CI: 1.449-2.950; p < 0.001) but did not predict this issue. However, an independent association between increasing SUA concentration and mortality was noted in a Cox proportional hazards regression model (adjusted HR = 1.740; 95% CI: 1.305-2.320; p < 0.001). Furthermore, hyperuricemia was an independent predictor of poor functional outcome within 3 months after stroke (OR = 2.482; 95% CI: 1.399-4.404; p = 0.002).

CONCLUSION

The prevalence of hyperuricemia in black African stroke patients is quite high and still remains a predictor of poor outcome.

[Evaluation of malaria rapid diagnostic test Optimal-IT® pLDH along the Plasmodium falciparum distribution limit in Mauritania]

Performance of the malaria Rapid Diagnostic Test (RDT) OptiMal-IT® was evaluated in Mauritania where malaria is low and dependent on a short transmission season. Slide microscopy was considered as the reference method of diagnosis. Febrile patients with suspected malaria were recruited from six health facilities, 3 urban and 3 rural, during two periods (December 2011 to February 2012, and August 2012 to March 2013). Overall, 780 patients were sampled, with RDT and thick blood film microscopy results being obtained for 759 of them. Out of 774 slides examined, of which 200 were positive, P. falciparum and P. vivax mono-infections were detected in 63.5% (127) and 29.5% (59), while P. falciparum/P. vivax coinfections were detected in 7% (14). Both species were observed in all study sites, although in significantly different proportions. The proportions of thick blood film and OptiMal-IT® RDT positive individuals was 26.3% and 30.3% respectively. Sensitivity and specificity of OptiMal-IT® RDT were 89% [95% CI, 84.7-93.3] and 91.1% [88.6-93.4]. Positives and negative predictive values were 78.1% [72.2-83.7] and 95.9% [94.1-97.5]. These diagnostic values are similar to those generally reported elsewhere, and support the use of RDTs as the main diagnostic tool for malaria in Mauritanian health facilities. In the future, choice of RDTs to be used must take account of thermostability in a hot, dry environment and their ability to detect P. falciparum and P. vivax.

iTRAQ-Based Quantitative Proteomic Analysis of the Potentiated and Dormant Antler Stem Cells

As the only known organ that can completely regenerate in mammals, deer antler is of real significance in the field of regenerative medicine. Recent studies have shown that the regenerative capacity of the antlers comes from the pedicle periosteum and the cells resident in the periosteum possess the attributes of stem cells. Currently, the molecular mechanism of antler regeneration remains unclear. In the present study, we compared the potentiated and dormant antler stem cells using isobaric tags for the relative and absolute quantification (iTRAQ) labeling of the peptides, coupled with two-dimensional liquid chromatography-tandem mass spectrometry (LC-MS/MS) to compare the proteome profiles. Proteins were identified by searching against the NCBI nr database and our own Cervine transcriptome database, and bioinformatics analysis was conducted to identify the differentially expressed proteins. Based on this searching strategy, we identified 169 differentially expressed proteins in total, consisting of 70 up- and 99 down-regulated in the potentiated vs. dormant antler stem cells. Reliability of the iTRAQ was confirmed via quantitative real-time polymerase chain reaction (qRT-PCR) to measure the expression of selected genes. We identified transduction pathways through the Kyoto Encyclopedia of Genes and Genomes (KEGG) database, such as HIF-1 and PI3K-AKT signaling pathways that play important roles in regulating the regeneration of antlers. In summary, the initiation stage of antler regeneration, a process from dormant to potentiated states in antler stem cells, is regulated by multiple proteins and complicated signal networks.

Cloning and Characterization of a Nanog Pseudogene in Sika Deer (Cervus nippon)

Nanog plays a crucial role in the maintenance of stem cell pluripotency. Annual full regeneration of deer antlers has been shown to be a stem cell-based process, and antler stem cells (ASCs) reportedly express Nanog. In the present study, we found that Nanog RNA expressed by ASCs was a pseudogene (Nanog-ps). The coding sequence of Nanog-ps was 93.1% homologous to that of bovine Nanog, but with two missing nucleotides after position 391. Deletion of the two nucleotides in Nanog-ps resulted in a frame-shift mutation, suggesting that Nanog-ps would not encode a normal Nanog protein. Overexpression of Nanog-ps failed to affect downstream genes of Nanog or to enhance cell proliferation in the ASCs. However, this pseudogene was transcribed in the ASCs and encoded a nuclear protein; the expression levels of Nanog-ps were also related to the degree of stemness in antler cells. Here, we reported this pseudogene, because it could serve as a useful marker for identifying ASCs and evaluating the degree of their stemness.

MicroRNA profiling of antler stem cells in potentiated and dormant states and their potential roles in antler regeneration

MicroRNAs (miRNAs) can effectively regulate gene expression at the post-transcriptional level and play a critical role in tissue growth, development and regeneration. Our previous studies showed that antler regeneration is a stem cell-based process and antler stem cells reside in the periosteum of a pedicle, the permanent bony protuberance, from which antler regeneration takes place. Antlers are the only mammalian organ that can fully regenerate and hence provide a unique opportunity to identify miRNAs that are involved in organ regeneration. In the present study, we used next generation sequencing technology sequenced miRNAs of the stem cells derived from either the potentiated or the dormant pedicle periosteum. A population of both conserved and 20 deer-specific miRNAs was identified. These conserved miRNAs were derived from 453 homologous hairpin precursors across 88 animal species, and were further grouped into 167 miRNA families. Among them, the miR-296 is embryonic stem cell-specific. The potentiation process resulted in the significant regulation (>±2 Fold, q value <0.05) of conserved miRNAs; 8 miRNA transcripts were down- and 6 up-regulated. Several GO biology processes and the Wnt, MAPK and TGF-beta signaling pathways were found to be up-regulated as part of antlerogenic stem cell potentiation process. This research has identified miRNAs that are associated either with the dormant or the potentiated antler stem cells and identified some target miRNAs for further research into their role played in mammalian organ regeneration.

An examination of the origin and evolution of additional tandem repeats in the mitochondrial DNA control region of Japanese sika deer (Cervus Nippon)

Tandem repeat units are only detected in the left domain of the mitochondrial DNA control region in sika deer. Previous studies showed that Japanese sika deer have more tandem repeat units than its cousins from the Asian continent and Taiwan, which often have only three repeat units. To determine the origin and evolution of these additional repeat units in Japanese sika deer, we obtained the sequence of repeat units from an expanded dataset of the control region from all sika deer lineages. The functional constraint is inferred to act on the first repeat unit because this repeat has the least sequence divergence in comparison to the other units. Based on slipped-strand mispairing mechanisms, the illegitimate elongation model could account for the addition or deletion of these additional repeat units in the Japanese sika deer population. We also report that these additional repeat units could be occurring in the internal positions of tandem repeat regions, possibly via coupling with a homogenization mechanism within and among these lineages. Moreover, the increased number of repeat units in the Japanese sika deer population could reflect a balance between mutation and selection, as well as genetic drift.

[Risk factors and clinical aspects of myocardial infarction in patients younger than 40 years in the Point G Teaching Hospital]

A retrospective and analytical study was conducted, over 9 years, from January 2004 to December 2012. It included 10 inpatients and took place at the cardiology service of the Point G teaching hospital. Its goals were to assess cardiovascular risk factors, the delay between the clinical onset and admission and to describe ECG changes and echocardiographic changes of myocardial infarction in patients under 40 year-old. Young patients accounted for 6.8% of MI admissions with a male predominance of 90%. The disease frequency has increased with age, 40% were within 38-40 year-old range, the risk factors were predominantly smoking 80%, Stress 50%, High Blood Pressure 40% and dyslipidemia 20%. Typical chest pain was the most common recorded symptom. Anterior necrosis was the most common of electrical pattern, 8 out 10 times the ejection fraction was down and segmental kinetic was impaired in 60% of patients on echocardiography. Over 3 quarters of patients were admitted 12 hours after the onset of symptoms and the evolution during hospitalization was good with no fatality.