Nerve growth factor mRNA expression in the regenerating antler tip of red deer (Cervus elaphus)

MiRNA Profiling and Its Potential Roles in Rapid Growth of Velvet Antler in Gansu Red Deer (Cervus elaphus kansuensis)

A significant variety of cell growth factors are involved in the regulation of antler growth, and the fast proliferation and differentiation of various tissue cells occur during the yearly regeneration of deer antlers. The unique development process of velvet antlers has potential application value in many fields of biomedical research. Among them, the nature of cartilage tissue and the rapid growth and development process make deer antler a model for studying cartilage tissue development or rapid repair of damage. However, the molecular mechanisms underlying the rapid growth of antlers are still not well studied. MicroRNAs are ubiquitous in animals and have a wide range of biological functions. In this study, we used high-throughput sequencing technology to analyze the miRNA expression patterns of antler growth centers at three distinct growth phases, 30, 60, and 90 days following the abscission of the antler base, in order to determine the regulatory function of miRNA on the rapid growth of antlers. Then, we identified the miRNAs that were differentially expressed at various growth stages and annotated the functions of their target genes. The results showed that 4319, 4640, and 4520 miRNAs were found in antler growth centers during the three growth periods. To further identify the essential miRNAs that could regulate fast antler development, five differentially expressed miRNAs (DEMs) were screened, and the functions of their target genes were annotated. The results of KEGG pathway annotation revealed that the target genes of the five DEMs were significantly annotated to the "Wnt signaling pathway", "PI3K-Akt signaling pathway", "MAPK signaling pathway", and "TGF-β signaling pathway", which were associated with the rapid growth of velvet antlers. Therefore, the five chosen miRNAs, particularly ppy-miR-1, mmu-miR-200b-3p, and novel miR-94, may play crucial roles in rapid antler growth in summer.

lncRNA Sequencing of Antler Mesenchymal Tissue Revealed that the Regulatory Network of Antler Cell Proliferation and Differentiation

Antlers have been widely studied due to their unique physiological characteristics, such as rapid growth, periodic shedding and regeneration. However, little is known about how antler growth is regulated by long non-coding RNA (lncRNA). The aim of the present study was to identify the lncRNAs expression profile and explore the function of lncRNAs during the antler growth. Herein, RNA-sequencing technology (RNA-seq) was performed on the three growth periods (early developmental period: EP, middle developmental period: MP, later developmental period: LP) of male sika deer (Cervus nippon) antler, 16 differentially expressed lncRNAs (DE lncRNAs) and 11 DE lncRNAs were identified in EP vs MP and MP vs LP related to cell proliferation and cell differentiation, respectively. Finally, lncRNAs-mRNAs co-expression networks were constructed based on the identified DE lncRNAs and their potential trans-target genes. The result reveals that lncRNAs may play diverse roles in different periods of antler growth. It provides a novel perspective for revealing the molecular mechanism of antler growth.

The periosteum: a simple tissue with many faces, with special reference to the antler-lineage periostea

Periosteum is a thin membrane covering bone surfaces and consists of two layers: outer fibrous layer and inner cambium layer. Simple appearance of periosteum has belied its own complexity as a composite structure for physical bone protection, mechano-sensor for sensing mechanical loading, reservoir of biochemical molecules for initiating cascade signaling, niche of osteogenic cells for bone formation and repair, and "umbilical cord" for nourishing bone tissue. Periosteum-derived cells (PDCs) have stem cell attributes: self-renewal (no signs of senescence until 80 population doublings) and multipotency (differentiate into fibroblasts, osteoblasts, chondrocytes, adipocytes and skeletal myocytes). In this review, we summarized the currently available knowledge about periosteum and with special references to antler-lineage periostea, and demonstrated that although periosteum is a type of simple tissue in appearance, with multiple faces in functions; antler-lineage periostea add another dimension to the properties of somatic periostea: capable of initiation of ectopic organ formation upon transplantation and full mammalian organ regeneration when interacted with the covering skin. Very recently, we have translated this finding into other mammals, i.e. successfully induced partial regeneration of the amputated rat legs. We believe further refinement along this line would greatly benefit human health.

Bioactive Molecular Discovery Using Deer Antlers as a Model of Mammalian Regeneration

The ability to activate and regulate stem cells during wound healing and tissue regeneration is a promising field that is resulting in innovative approaches in the field of regenerative medicine. The regenerative capacity of invertebrates has been well documented; however, in mammals, stem cells that drive organ regeneration are rare. Deer antlers are the only known mammalian structure that can annually regenerate to produce a tissue containing dermis, blood vessels, nerves, cartilage, and bone. The neural crest derived stem cells that drive this process result in antlers growing at up to 2 cm/day. Deer antlers thus provide superior attributes compared to lower-order animal models, when investigating the regulation of stem cell-based regeneration. Antler stem cells can therefore be used as a model to investigate the bioactive molecules, biological processes, and pathways involved in the maintenance of a stem cell niche, and their activation and differentiation during organ formation. This review examines stem cell-based regeneration with a focus on deer antlers, a neural crest stem cell-based mammalian regenerative structure. It then discusses the omics technical platforms highlighting the proteomics approaches used for investigating the molecular mechanisms underlying stem cell regulation in antler tissues.

Pressure Algometry Validation and Determination of Efficacy of Articaine Hydrochloride Ring Block in Antler Removal in Red Deer (Cervus elaphus)

Simple Summary

Red deer (Cervus elaphus) are farmed in New Zealand for the production of velvet antler. Velvet is harvested as living antler tissue, and currently lignocaine is the only licensed local anaesthetic approved for deer antler removal in New Zealand. The use of lignocaine is not without consequences, including drug residues in harvested velvet antler tissue and its short acting analgesic effect. This study was designed to determine the effect of local anaesthetic, articaine hydrochloride as an alternative treatment and to establish the baseline measurements of mechanical nociceptive threshold in 40 male yearling red deer. Ten of the forty enrolled deer were selected for the articaine efficacy study. The mechanical nociceptive thresholds were measured using a handheld algometer applied at 4 points; the cranial, medial, caudal and lateral aspects of the base of each antler. The force applied, which resulted in a movement by the animal, was recorded in newtons (N). This study showed that nociceptive threshold response in deer could be reliably measured, and articaine proved to be a promising alternative for velveting the deer antlers.

Abstract

New Zealand deer farming centres on the production of meat and velvet antler. Velvet antler removal is a painful procedure and currently, New Zealand Animal Welfare regulations dictate surgical removal of velvet antlers under lignocaine anaesthesia. To improve our knowledge on the efficacy and duration of other local anaesthetics to mitigate pain after antler removal, it is important to accurately assess and quantify pain arising from antler removal. Therefore, the current study was designed to validate mechanical nociceptive threshold (MNT) testing using a Wagner hand-held algometer, and to apply this methodology to assess the efficacy and duration of action of articaine for antler removal in deer. Baseline force (N) required to elicit the nociceptive response was recorded in 40 yearling male red deer on three alternate days. Ten of the 40 animals were selected for antler removal after administration of 4% articaine hydrochloride as a ring block. The duration of analgesic efficacy of articaine was assessed by algometry across 5 time points. There was a significant difference in MNTs among the three days (day 3 versus day 1 (p < 0.0001), day 2 versus day 1 (p < 0.0001), and day 1 versus day 2 (p < 0.01)). Positive correlations were observed between weight, antler length and thresholds. The MNT values remained above 20N for 6 h after removal of velvet antlers under the articaine ring block. This study provides valuable information about the use of MNT in red deer. These findings lay a foundation for future studies in the topics of peri-operative and postoperative pain management in deer antler removal, and a possible alternative use for articaine.

Comparative transcriptome analysis of the main beam and brow tine of sika deer antler provides insights into the molecular control of rapid antler growth

Background

Deer antlers have become a valuable model for biomedical research due to the capacities of regeneration and rapid growth. However, the molecular mechanism of rapid antler growth remains to be elucidated. The aim of the present study was to compare and explore the molecular control exerted by the main beam and brow tine during rapid antler growth.

Methods

The main beams and brow tines of sika deer antlers were collected from Chinese sika deer (Cervus nippon) at the rapid growth stage. Comparative transcriptome analysis was conducted using RNA-Seq technology. Differential expression was assessed using the DEGseq package. Functional Gene Ontology (GO) enrichment analysis was accomplished using a rigorous algorithm according to the GO Term Finder tool, and KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway enrichment analysis was accomplished with the R function phyper, followed by the hypergeometric test and Bonferroni correction. Quantitative real-time polymerase chain reaction (qRT-PCR) was carried out to verify the RNA levels for differentially expressed mRNAs.

Results

The expression levels of 16 differentially expressed genes (DEGs) involved in chondrogenesis and cartilage development were identified as significantly upregulated in the main beams, including transcription factor SOX-9 (Sox9), collagen alpha-1(II) chain (Col2a1), aggrecan core protein (Acan), etc. However, the expression levels of 17 DEGs involved in endochondral ossification and bone formation were identified as significantly upregulated in the brow tines, including collagen alpha-1(X) chain (Col10a1), osteopontin (Spp1) and bone sialoprotein 2 (Ibsp), etc.

Conclusion

These results suggest that the antler main beam has stronger growth capacity involved in chondrogenesis and cartilage development compared to the brow tine during rapid antler growth, which is mainly achieved through regulation of Sox9 and its target genes, whereas the antler brow tine has stronger capacities of endochondral bone formation and resorption compared to the main beam during rapid antler growth, which is mainly achieved through the genes involved in regulating osteoblast and osteoclast activities. Thus, the current research has deeply expanded our understanding of the intrinsic molecular regulation displayed by the main beam and brow tine during rapid antler growth.

Genetic basis of ruminant headgear and rapid antler regeneration

Ruminants are the only extant mammalian group possessing bony (osseous) headgear. We obtained 221 transcriptomes from bovids and cervids and sequenced three genomes representing the only two pecoran lineages that convergently lack headgear. Comparative analyses reveal that bovid horns and cervid antlers share similar gene expression profiles and a common cellular basis developed from neural crest stem cells. The rapid regenerative properties of antler tissue involve exploitation of oncogenetic pathways, and at the same time some tumor suppressor genes are under strong selection in deer. These results provide insights into the evolutionary origin of ruminant headgear as well as mammalian organ regeneration and oncogenesis.

Antler stem cell-conditioned medium stimulates regenerative wound healing in rats

Background

When the deer antler is cast, it leaves a cutaneous wound that can achieve scarless healing due to the presence of antler stem cells (ASCs). This provides an opportunity to study regenerative wound healing.

Methods

In this study, we investigated the therapeutic effects and mechanism of antler stem cell-conditioned medium (ASC-CM) on cutaneous wound healing in rats. In vitro, we investigated the effects of the ASC-CM on proliferation of HUVEC and NIH-3T3 cell lines. In vivo, we evaluated the effects of ASC-CM on cutaneous wound healing using full-thickness skin punch-cut wounds in rats.

Results

The results showed that ASC-CM significantly stimulated proliferation of the HUVEC and NIH-3T3 cells in vitro. In vivo, completion of healing of the rat wounds treated with ASC-CM was on day 16 (± 3 days), 9 days (± 2 days) earlier than the control group (DMEM); the area of the wounds treated with ASC-CM was significantly smaller (p < 0.05) than the two control groups. Further molecular characterization showed that the ratios of Col3A1/Col1A2, TGF-β3/TGF-β1, MMP1/TIMP1, and MMP3/TIMP1 significantly increased (p < 0.01) in the healed tissue in the ASC-CM group.

Conclusions

In conclusion, ASC-CM effectively accelerated the wound closure rate and enhanced the quality of healing, which might be through transforming wound dermal fibroblasts into the fetal counterparts. Therefore, the ASC-CM may have potential to be developed as a novel cell-free therapeutic for scarless wound healing.

Antlers - Evolution, development, structure, composition, and biomechanics of an outstanding type of bone

Antlers are bony appendages of deer that undergo periodic regeneration from the top of permanent outgrowths (the pedicles) of the frontal bones. Of the "less familiar" bone types whose study was advocated by John Currey to gain a better understanding of structure-function relationships of mineralized tissues and organs, antlers were of special interest to him. The present review summarizes our current knowledge about the evolution, development, structure, mineralization, and biomechanics of antlers and how their formation is affected by environmental factors like nutrition. Furthermore, the potential role of antlers as a model in bone biology and several fields of biomedicine as well as their use as a monitoring tool in environmental studies are discussed.

ALWPs Improve Cognitive Function and Regulate Aβ Plaque and Tau Hyperphosphorylation in a Mouse Model of Alzheimer's Disease

Recently, we reported that ALWPs, which we developed by combining Liuwei Dihuang pills (LWPs) with antler, regulate the LPS-induced neuroinflammatory response and rescue LPS-induced short- and long-term memory impairment in wild-type (WT) mice. In the present study, we examined the effects of ALWPs on Alzheimer’s disease (AD) pathology and cognitive function in WT mice as well as 5x FAD mice (a mouse model of AD). We found that administration of ALWPs significantly reduced amyloid plaque levels in 5x FAD mice and significantly decreased amyloid β (Aβ) levels in amyloid precursor protein (APP)-overexpressing H4 cells. In addition, ALWPs administration significantly suppressed tau hyperphosphorylation in 5x FAD mice. Oral administration of ALWPs significantly improved long-term memory in scopolamine (SCO)-injected WT mice and 5x FAD mice by altering dendritic spine density. Importantly, ALWPs promoted spinogenesis in primary hippocampal neurons and WT mice and modulated the dendritic spine number in an extracellular signal-regulated kinase (ERK)-dependent manner. Taken together, our results suggest that ALWPs are a candidate therapeutic drug for AD that can modulate amyloid plaque load, tau phosphorylation, and synaptic/cognitive function.

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.

Common themes in tetrapod appendage regeneration: a cellular perspective

Complete and perfect regeneration of appendages is a process that has fascinated and perplexed biologists for centuries. Some tetrapods possess amazing regenerative abilities, but the regenerative abilities of others are exceedingly limited. The reasons underlying these differences have largely remained mysterious. A great deal has been learned about the morphological events that accompany successful appendage regeneration, and a handful of experimental manipulations can be reliably applied to block the process. However, only in the last decade has the goal of attaining a thorough molecular and cellular biological understanding of appendage regeneration in tetrapods become within reach. Advances in molecular and genetic tools for interrogating these remarkable events are now allowing for unprecedented access to the fundamental biology at work in appendage regeneration in a variety of species. This information will be critical for integrating the large body of detailed observations from previous centuries with a modern understanding of how cells sense and respond to severe injury and loss of body parts. Understanding commonalities between regenerative modes across diverse species is likely to illuminate the most important aspects of complex tissue regeneration.

DNA methylation and mRNA expression of COL6A3 in antler mesenchyme of female and male reindeer

BACKGROUD

Reindeer is the only deer species that both male and female produce antlers, which provides a particularly interesting case in studying the differences between antlers of the two sexes. Alpha 3(VI) Collagen Gene (COL6A3), forms a microfibrillar network associated with the structural integrity and biomechanical properties, has been found to be one of the differentially expressed genes in antler mesenchyme of female and male reindeer.

OBJECTIVE AND METHODS

The promoter sequence of reindeer COL6A3 gene was obtained using the cloning technology and analyzed by the bioinformatics methods. Bisulfite sequencing PCR (BSP) was used to detect the methylation status of the COL6A3 promoter in reindeer antler mesenchyme. Real-time quantitative PCR was used to detect COL6A3 expression in the antler mesenchyme of female and male reindeer.

RESULTS

Sequence analysis revealed that the reindeer COL6A3 partial promoter sequence was 983 bp including the possible promoter region at + 105 bp to + 155 bp. Homology and phylogenetic analysis indicated that the COL6A3 promoter of reindeer had the closest genetic distance with Bos taurus, Capra hircus and Ovis aries. BSP results indicated that the methylation level of COL6A3 promoter in the female reindeer antler mesenchyme was significantly higher than in the male. Correlating with increased methylation status, we also found that COL6A3 mRNA expression in female reindeer antler mesenchyme was significantly lower than in the male.

CONCLUSION

The higher methylation level of the COL6A3 gene in female reindeer antler mesenchyme coincides with decreased COL6A3 mRNA expression, thereby affecting the transposon silencing mechanism and possibly contributing to apparent differences of antlers in female and male reindeer.

Transcriptomic characterization elucidates a signaling network that controls antler growth

Deer antlers are amazing appendages with the fastest growth rate among mammalian organs. Antler growth is driven by the growth center through a modified endochondral ossification process. Thus, identification of signaling pathways functioning in antler growth center would help us to uncover the underlying molecular mechanism of rapid antler growth. Furthermore, exploring and dissecting the molecular mechanism that regulates antler growth is extremely important and helpful for identifying methods to enhance long bone growth and treat cartilage- and bone-related diseases. In this study, we build a comprehensive intercellular signaling network in antler growth centers from both the slow growth stage and rapid growth stage using a state-of-art RNA-Seq approach. This network includes differentially expressed genes that regulate the activation of multiple signaling pathways, including the regulation of actin cytoskeleton, calcium signaling, and adherens junction. These signaling pathways coordinately control multiple biological processes, including chondrocyte proliferation and differentiation, matrix homeostasis, mechanobiology, and aging processes, during antler growth in a comprehensive and efficient manner. Therefore, our study provides novel insights into the molecular mechanisms regulating antler growth and provides valuable and powerful insight for medical research on therapeutic strategies targeting skeletal disorders and related cartilage and bone diseases.

An Aqueous Extract of Herbal Medicine ALWPs Enhances Cognitive Performance and Inhibits LPS-Induced Neuroinflammation via FAK/NF-κB Signaling Pathways

Recent studies have shown that Liuwei Dihuang pills (LWPs) can positively affect learning, memory and neurogenesis. However, the underlying molecular mechanisms are not understood. In the present study, we developed ALWPs, a mixture of Antler and LWPs, and investigated whether ALWPs can affect neuroinflammatory responses. We found that ALWPs (500 mg/ml) inhibited lipopolysaccharide (LPS)-induced proinflammatory cytokine IL-1β mRNA levels in BV2 microglial cells but not primary astrocytes. ALWPs significantly reduced LPS-induced cell-surface levels of TLR4 to alter neuroinflammation. An examination of the molecular mechanisms by which ALWPs regulate the LPS-induced proinflammatory response revealed that ALWPs significantly downregulated LPS-induced levels of FAK phosphorylation, suggesting that ALWPs modulate FAK signaling to alter LPS-induced IL-1β levels. In addition, treatment with ALWPs followed by LPS resulted in decreased levels of the transcription factor NF-κB in the nucleus compared with LPS alone. Moreover, ALWPs significantly suppressed LPS-induced BV2 microglial cell migration. To examine whether ALWPs modulate learning and memory in vivo, wild-type C57BL/6J mice were orally administered ALWPs (200 mg/kg) or PBS daily for 3 days, intraperitoneally injected (i.p.) with LPS (250 μg/kg) or PBS, and assessed in Y maze and NOR tests. We observed that oral administration of ALWPs to LPS-injected wild-type C57BL/6J mice significantly rescued short- and long-term memory. More importantly, oral administration of ALWPs to LPS-injected wild-type C57BL/6J mice significantly reduced microglial activation in the hippocampus and cortex. Taken together, our results suggest that ALWPs can suppress neuroinflammation-associated cognitive deficits and that ALWPs have potential as a drug for neuroinflammation/neurodegeneration-related diseases, including Alzheimer's disease (AD).

The red deer Cervus elaphus genome CerEla1.0: sequencing, annotating, genes, and chromosomes

We present here the de novo genome assembly CerEla1.0 for the red deer, Cervus elaphus, an emblematic member of the natural megafauna of the Northern Hemisphere. Humans spread the species in the South. Today, the red deer is also a farm-bred animal and is becoming a model animal in biomedical and population studies. Stag DNA was sequenced at 74× coverage by Illumina technology. The ALLPATHS-LG assembly of the reads resulted in 34.7 × 10³ scaffolds, 26.1 × 10³ of which were utilized in Cer.Ela1.0. The assembly spans 3.4 Gbp. For building the red deer pseudochromosomes, a pre-established genetic map was used for main anchor points. A nearly complete co-linearity was found between the mapmarker sequences of the deer genetic map and the order and orientation of the orthologous sequences in the syntenic bovine regions. Syntenies were also conserved at the in-scaffold level. The cM distances corresponded to 1.34 Mbp uniformly along the deer genome. Chromosomal rearrangements between deer and cattle were demonstrated. 2.8 × 10⁶ SNPs, 365 × 10³ indels and 19368 protein-coding genes were identified in CerEla1.0, along with positions for centromerons. CerEla1.0 demonstrates the utilization of dual references, i.e., when a target genome (here C. elaphus) already has a pre-established genetic map, and is combined with the well-established whole genome sequence of a closely related species (here Bos taurus). Genome-wide association studies (GWAS) that CerEla1.0 (NCBI, MKHE00000000) could serve for are discussed.

Protective effects of Cervus nippon Temminck velvet antler polypeptides against MPP+‑induced cytotoxicity in SH‑SY5Y neuroblastoma cells

The aim of the present study was to examine the protective effects and mechanism of sika deer (Cervus nippon Temminck) velvet antler polypeptides (VAPs) against MPP⁺ exposure in the SH-SY5Y human neuroblastoma cell line. MPP⁺ cytotoxicity and the protective effects of VAPs on the SH-SY5Y cells were determined using an MTT assay. Cell apoptosis and mitochondrial membrane potential were detected using Hoechst 33342 and Rhodamine123 staining, respectively. Endoplasmic reticulum (ER) stress-related reactive oxygen species (ROS) production in the SH-SY5Y cells was detected using 2′,7′-dichlorodihydrofluorescein diacetate fluorescent probes. The expression levels of proteins, including caspase-12, glucose regulated protein 78 (GRP78), CCAAT/enhancer binding protein homologous protein (CHOP) and phosphorylated c-Jun N-terminal kinase (p-JNK) were detected using western blot analysis. The results showed that the half inhibitory concentration of MPP⁺ at 72 h was 120.9 µmol/l, and that 62.5, 125, and 250 µg/ml concentrations of VAPs protected the SH-SY5Y cells under MPP⁺ exposure. When exposed to 120.9 µmol/l MPP⁺, changes in cell nucleus morphology, mitochondrial membrane potential and intracellular ROS were observed. VAPs at concentrations of 62.5, 125, 250 µg/ml reduced this damage. Western blot analysis showed that protein expression levels of caspase-12, GRP78 and p-JNK were upregulated in the SH-SY5Y cells exposed to 120.9 µmol/l MPP⁺ for 72 h. In addition, 62.5, 125, and 250 µg/ml VAPs downregulated the expression levels of caspase-12 and p-JNK in a concentration- dependent manner, particularly the p-JNK pathway. The effects of VAPs on GRP78 and CHOP were weak. In conclusion, MPP⁺-induced SH-SY5Y cell death may be linked to ER stress. VAPs prevented MPP⁺-induced SH-SY5Y cell death by affecting the p-JNK pathway and caspase-12-mediated apoptosis. These findings assist in understanding the mechanism underlying the protective effect of VAPs on neurons.

NGF-TrkA Signaling by Sensory Nerves Coordinates the Vascularization and Ossification of Developing Endochondral Bone

Developing tissues dictate the amount and type of innervation they require by secreting neurotrophins, which promote neuronal survival by activating distinct tyrosine kinase receptors. Here, we show that nerve growth factor (NGF) signaling through neurotrophic tyrosine kinase receptor type 1 (TrkA) directs innervation of the developing mouse femur to promote vascularization and osteoprogenitor lineage progression. At the start of primary ossification, TrkA-positive axons were observed at perichondrial bone surfaces, coincident with NGF expression in cells adjacent to centers of incipient ossification. Inactivation of TrkA signaling during embryogenesis in TrkA(F592A) mice impaired innervation, delayed vascular invasion of the primary and secondary ossification centers, decreased numbers of Osx-expressing osteoprogenitors, and decreased femoral length and volume. These same phenotypic abnormalities were observed in mice following tamoxifen-induced disruption of NGF in Col2-expressing perichondrial osteochondral progenitors. We conclude that NGF serves as a skeletal neurotrophin to promote sensory innervation of developing long bones, a process critical for normal primary and secondary ossification.

Cornu cervi pantotrichum Pharmacopuncture Solution Facilitate Hair Growth in C57BL/6 Mice

Objectives:

Cornu cervi pantotrichum (CCP) has been widely used in Korean and China, as an anti-fatigue, anti-aging, and tonic agent to enhance the functions of the reproductive and the immune systems. Because CCP has various growth factors that play important roles in the development of hair follicles, we examined whether CCP pharmacopuncture solution (CCPPS) was capable of promoting hair growth in an animal model.

Methods:

One day after hair depilation, CCPPS were topically applied to the dorsal skin of C57BL/6 mice once a day for 15 days. Hair growth activity was evaluated by using macro- and microscopic observations. Dorsal skin tissues were stained with hematoxylin and eosin. Expressions of bromodeoxyuridine (BrdU), proliferating cell nuclear antigen (PCNA), and fibroblast growth factor (FGF)-7 were examined by using immunohistochemical staining. A reverse transcription polymerase chain reaction (RT-PCR) analysis was also conducted to measure the messenger RNA (mRNA) expression of FGF-7.

Results:

CCPPS induced more active hair growth than normal saline. Histologic analysis showed enlargement of the dermal papilla, elongation of the hair shaft, and expansion of hair thickness in CCPPS treated mice, indicating that CCPPS effectively induced the development of anagen. CCPPS treatment markedly increased the expressions of BrdU and PCNA in the hair follicles of C57BL/6 mice. In addition, CCPPS up regulated the expression of FGF-7, which plays an important role in the development of hair follicles.

Conclusion:

These results reveal that CCPPS facilitates hair re-growth by proliferation of hair follicular cells and up-regulation of FGF-7 and suggest that CCPPS can potentially be applied as an alternative treatment for patients with alopecia.

Deer antler regeneration: a stem cell-based epimorphic process

Full regeneration of deer antlers, a bona fide epimorphic process in mammals, is in defiance of the general rule of nature. Revealing the mechanism underlying this unique exception would place us in a better position to promote organ regeneration in humans. Antler regeneration takes place in yearly cycles from its pedicle, a permanent protuberance on the frontal bone. Both growing antlers and pedicles consist of internal (cartilage and bone) and external components (skin, blood vessels, and nerves). Recent studies have demonstrated that the regeneration of both internal and external components relies on the presence of pedicle periosteum (PP). PP cells express key embryonic stem cell markers (Oct4, Nanog, and SOX2) and are multipotent, so are termed antler stem cells. Now it is clear that proliferation and differentiation of PP cells directly forms internal antler components; however, how PP initiates and maintains the regeneration of external antler components is thus far not known. Based on the direct as well as indirect evidence that is presented in this review, I put forward the following hypothesis to address this issue. The full regenerative ability of external antler tissue components is achieved through PP-derived chemical induction and PP-derived mechanical stimulation: the former triggers the regeneration of these external components, whereas the latter drives their rapid elongation. Eventual identification of the putative PP-derived chemical factors would open up a new avenue for devising effective therapies for lesions involving each of these tissue components, be they traumatic, degenerative, or linked to developmental (genetic) anomalies.

Factors promoting neurite outgrowth during deer antler regeneration

Every year male deers completely regenerate their antlers. During this process, antlers are reinnervated by sensory fibers, growing at the highest rate recorded for any adult mammal. Despite its clinical potential, only a few studies have dealt with this fascinating phenomenon. Among the possible factors underlying fast growth of the antler's innervation, the effects of the antler's endocrine and paracrine factors were evaluated, using an in vitro assay for sensory neurite growth. We found that soluble molecules secreted by the velvet, the modified skin that covers the antler, strongly promote neurite outgrowth. Using specific blocking antibodies, we demonstrated that nerve growth factor is partially responsible for these effects, although other unidentified molecules are also involved. On the contrary, neither endocrine serum factors nor antler substrates promoted neurite outgrowth, although antler substrata from deep velvet layers cause neurite outgrowth orientation. Taken together, our results point to the existence in the deep velvet of an environment that promotes oriented axon growth, in agreement with the distribution of the antler innervation.

Gene expression of axon growth promoting factors in the deer antler

The annual regeneration cycle of deer (Cervidae, Artiodactyla) antlers represents a unique model of epimorphic regeneration and rapid growth in adult mammals. Regenerating antlers are innervated by trigeminal sensory axons growing through the velvet, the modified form of skin that envelopes the antler, at elongation velocities that reach one centimetre per day in the common deer (Cervus elaphus). Several axon growth promoters like NT-3, NGF or IGF-1 have been described in the antler. To increase the knowledge on the axon growth environment, we have combined different gene-expression techniques to identify and characterize the expression of promoting molecules not previously described in the antler velvet. Cross-species microarray analyses of deer samples on human arrays allowed us to build up a list of 90 extracellular or membrane molecules involved in axon growth that were potentially being expressed in the antler. Fifteen of these genes were analysed using PCR and sequencing techniques to confirm their expression in the velvet and to compare it with the expression in other antler and skin samples. Expression of 8 axon growth promoters was confirmed in the velvet, 5 of them not previously described in the antler. In conclusion, our work shows that antler velvet provides growing axons with a variety of promoters of axon growth, sharing many of them with deer's normal and pedicle skin.

Bone marrow cells produce nerve growth factor and promote angiogenesis around transplanted islets

AIM: To clarify the mechanism by which bone marrow cells promote angiogenesis around transplanted islets.

METHODS: Streptozotocin induced diabetic BALB/c mice were transplanted syngeneically under the kidney capsule with the following: (1) 200 islets (islet group: n = 12), (2) 1-5 × 10⁶ bone marrow cells (bone marrow group: n = 11), (3) 200 islets and 1-5 × 10⁶ bone marrow cells (islet + bone marrow group: n = 13), or (4) no cells (sham group: n = 5). All mice were evaluated for blood glucose, serum insulin, serum nerve growth factor (NGF) and glucose tolerance (GTT) up to postoperative day (POD) 14. Histological assessment for insulin, von Willebrand factor (vWF) and NGF was performed at POD 3, 7 and 14.

RESULTS: Blood glucose level was lowest and serum insulin was highest in the islet + bone marrow group. Serum NGF increased in islet, bone marrow, and islet + bone marrow groups after transplantation, and there was a significant difference (P = 0.0496, ANOVA) between the bone marrow and sham groups. The number of vessels within the graft area was significantly increased in both the bone marrow and islet + bone marrow groups at POD 14 as compared to the islet alone group (21.2 ± 3.6 in bone marrow, P = 0.01, vs islet group, 22.6 ± 1.9 in islet + bone marrow, P = 0.0003, vs islet group, 5.3 ± 1.6 in islet-alone transplants). NGF was more strongly expressed in bone marrow cells compared with islets.

CONCLUSION: Bone marrow cells produce NGF and promote angiogenesis. Islet co-transplantation with bone marrow is associated with improvement of islet graft function.