Velvet antler polypeptide (VAP) protects against cerebral ischemic injury through NF-κB signaling pathway in vitro

OBJECTIVE

Velvet antler polypeptide (VAP) has been shown to play important roles in the immune and nervous systems. The purpose of this study was to investigate the protective effects of VAP on cerebral ischemic injury with the involvement of NF-κB signaling pathway in vitro.

MATERIALS AND METHODS

PC-12 cells stimulated by oxygen-glucose deprivation/reperfusion (OGD/R) was used to mimic cerebral ischemic injury in vitro. The levels of ROS, SOD, and intracellular concentrations of Ca2+ were measured by the relevant kits. Meanwhile, the expressions of inflammatory cytokines (IL-6, IL-1β, and TNF-α) were determined by ELISA kit assay. In addition, MTT, EdU, and flow cytometry assays were used to measure the cell proliferation and apoptosis. Besides which, the related proteins of NF-κB signaling pathway were measured by western blotting assay.

RESULTS

VAP alleviated cerebral ischemic injury by reducing OGD/R-induced oxidative stress, inflammation, and apoptosis in PC-12 cells in a time dependent manner. Mechanistically, VAP inhibited the levels of p-p65 and p-IkB-α in a time dependent manner, which was induced by OGD/R operation. Moreover, NF-κB agonist diprovocim overturned the suppression effects of VAP on OGD/R-induced oxidative stress, inflammation, and apoptosis in PC-12 cells.

CONCLUSIONS

The results demonstrate that VAP may alleviate cerebral ischemic injury by suppressing the activation of NF-κB signaling pathway.

Antler thymosin β10 reduces liver fibrosis via inhibiting TGF-β1/SMAD pathway

Hepatic stellate cell (HSC) activation is a crucial step in the development of liver fibrosis. Previous studies have shown that antler stem cells (AnSCs) inhibited HSC activation, suggesting that this may be achieved through secreting or releasing peptides. This study aimed to investigate whether AnSC-derived peptides (AnSC-P) could reduce liver fibrosis. The results showed that AnSC-P effectively reduced liver fibrosis in rats. Furthermore, we found that thymosin β10 (Tβ-10) was rich in AnSC-P, which may be the main component of AnSC-P contributing to the reduction in liver fibrosis. A further study showed that Tβ-10 reduced liver fibrosis in rats, with a reduction in HYP and MDA levels in the liver tissues, a decrease in the serum levels of ALP, ALT, AST, and TBIL and an increase in TP and ALB. Moreover, Tβ-10 decreased the expression levels of the genes related to the TGF-β/SMAD signaling pathway in vivo. In addition, Tβ-10 also inhibited TGF-β1-induced HSC activation and decreased the expression levels of the TGF-β/SMAD signaling pathway-related genes in HSCs in vitro. In conclusion, antler Tβ-10 is a potential drug candidate for the treatment of liver fibrosis, the effect of which may be achieved via inhibition of the TGFβ/SMAD signaling pathway.

Conditioned Media from Deer Antler Stem Cells Effectively Alleviate Type 1 Diabetes Mellitus Possibly via Inhibiting the NF-κB Signaling Pathway

BACKGROUND

Type 1 diabetes mellitus (T1D) represents a severe threat to human health. Persistent hyperglycemia and dyslipidemia can lead to damaged liver function, while effective interventions for these complications are currently lacking. Deer antler stem cells (AnSCs), a novel type of adult stem cells, significantly reduced liver injury, which was speculated to be achieved through the paracrine pathway.

METHODS

In this study, AnSC-conditioned medium (AnSC-CM) was used to treat C57BL/6 mice with T1D symptoms induced by streptozotocin (STZ). The therapeutic effects of AnSC-CM on T1D were evaluated, and the underlying mechanism was investigated.

RESULTS

It was shown that AnSC-CM alleviated the T1D symptom: decreased body weight, increased blood glucose levels and islet lesions, and reduced insulin secretion. Moreover, AnSC-CM treatment improved liver function and mitigated liver injury in T1D mice. Impressively, the therapeutic effects of AnSC-CM on T1D were better than those of bone marrow mesenchymal stem cell-CM (BMSC-CM). The mechanistic study revealed that AnSC-CM significantly downregulated the NF-κB signaling pathway in both pancreatic and liver tissues.

CONCLUSIONS

Therapeutic effects of AnSC-CM on STZ-induced T1D and liver injury may be achieved through targeting the NF-κB signaling pathway.

Deer antlers: the fastest growing tissue with least cancer occurrence

Deer antlers are a bony organ solely able to acquired distinct unique attributes during evolution and all these attributes are against thus far known natural rules. One of them is as the fastest animal growing tissue (2 cm/day), they are remarkably cancer-free, despite high cell division rate. Although tumor-like nodules on the long-lived castrate antlers in some deer species do occur, but they are truly benign in nature. In this review, we tried to find the answer to this seemingly contradictory phenomenon based on the currently available information and give insights into possible clinic application. The antler growth center is located in its tip; the most intensive dividing cells are resident in the inner layer of reserve mesenchyme (RM), and these cells are more adopted to osteosarcoma rather than to normal bone tissues in gene expression profiles but acquire their energy mainly through aerobic oxidative phosphorylation pathway. To counteract propensity of neoplastic transformation, antlers evolved highly efficient apoptosis exactly in the RM, unparalleled by any known tissues; and annual wholesale cast to jettison the corps. Besides, some strong cancer suppressive genes including p53 cofactor genes and p53 regulator genes are highly positively selected by deer, which would have certainly contributed to curb tumorigenesis. Thus far, antler extracts and RM cells/exosomes have been tried on different cancer models either in vitro or in vivo, and all achieved positive results. These positive experimental results together with the anecdotal folklore that regular consumption of velvet antler is living with cancer-free would encourage us to test antlers in clinic settings.

Protection of a novel velvet antler polypeptide PNP1 against cerebral ischemia-reperfusion injury

AIM

We isolated a novel polypeptide PNP1 from velvet antler and investigated the role of PNP1 in ischemia reperfusion and its associated mechanism.

METHODS

We built the ischemia reperfusion mouse model by the middle cerebral artery occlusion (MCAO) approach. Thereafter, PNP-1 was injected via the tail vein, and neurological function was scored. Meanwhile, the tissue injury level was detected through hematoxylin & eosin (HE) and immunohistochemical (IHC) staining, inflammatory factor levels were determined with enzyme-linked immunosorbent assay (ELISA), while protein levels through Western blotting. In addition, vascular endothelial cells were used to construct the oxygen-glucose deprivation (OGD) injury model in vitro, so as to detect the intervention effect of PNP1 on endothelial injury. Additionally, microglial cells were utilized to construct the inflammatory injury model to examine the impact of PNP1 on the polarization of microglial cells.

RESULTS

PNP1 suppressed hypoxic cerebral injury in MCAO mice, decreased the tissue inflammatory factors, promoted tissue angiogenesis, and reduced the ischemic penumbra area. Experimental results in vitro demonstrated that, PNP1 suppressed vascular endothelial cell injury, and inhibited microglial M1 polarization as well as inflammatory response.

CONCLUSION

Velvet antler polypeptide PNP1 isolated in this study has the anti-ischemic cerebral injury effect, and its mechanism is associated with suppressing vascular endothelial cell injury and microglial cell inflammatory response.

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.

Deer Velvet Antler Extracts Exert Anti-Inflammatory and Anti-Arthritic Effects on Human Rheumatoid Arthritis Fibroblast-Like Synoviocytes and Distinct Mouse Arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes joint deformity and disability. Deer velvet antler (DA), a traditional Chinese medicine, has been used to treat various types of arthritis for several thousands of years, but the underlying mechanisms are unknown. Herein, we investigated the anti-arthritic and anti-inflammatory effects of DA in vitro and in vivo. The ethyl acetate layer of DA ethanol extract (DA-EE-EA) was used to treat tumor necrosis factor (TNF)-[Formula: see text]-stimulated fibroblast-like synoviocyte MH7A cells, collagen-induced arthritis DBA/1 mice, and SKG mice with zymosan-induced arthritis. DA-EE-EA reduced nitric oxide production, prostaglandin E2 levels, and levels of pro-inflammatory cytokines including interleukin (IL)-1[Formula: see text], IL-6, and IL-8 in MH7A cells. DA-EE-EA also downregulated the phosphorylation of mitogen-activated protein kinase p38 and c-Jun N-terminal kinase and the translocation of nuclear factor kappa B p65. Intraperitoneal injection of DA-EE-EA for 3 weeks substantially reduced clinical arthritis scores in vivo models. Pathohistological images of the hind paws showed that DA-EE-EA reduced immune cell infiltration, synovial hyperplasia, and cartilage damage. The levels of pro-inflammatory cytokines, such as tumor necrosis factor alpha, IL-1[Formula: see text], IL-6, IL-8, IL-17A, and interferon-gamma, decreased in the hind paw homogenates of DA-EE-EA-treated mice. We also identified several potential components, such as hexadecanamide, oleamide, erucamide, and lysophosphatidylcholines, that might contribute to the anti-inflammatory effects of DA-EE-EA. In conclusion, DA-EE-EA has the potential to treat RA by regulating inflammatory responses. However, the individual components of DA-EE-EA and the underlying anti-inflammatory mechanisms need further investigation in future studies.

Hard antler extract inhibits invasion and epithelial-mesenchymal transition of triple-negative and Her-2+ breast cancer cells by attenuating nuclear factor-κB signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Hard antler extract (HAE) is a traditional Chinese medicine and has potent antitumor, antioxidative, anti-inflammatory, and immunomodulatory activities. Previous studies have demonstrated that HAE can inhibit human prostate cancer metastasis and murine breast cancer proliferation. However, the effect of HAE on human breast cancer cells has not been clarified.

AIM OF THE STUDY

To investigate the effects and underlying mechanism of HAE on self-renewal of stem-like cells and spontaneous and transforming growth factor (TGF)-β1-enhanced wound healing, invasion and epithelial-mesenchymal transition (EMT) in breast cancer cells.

METHODS

HAE was prepared from sika deer by sequential enzymatic digestions and the active compounds were determined by HPLC. The effects of HAE on the viability, mammosphere formation, wound healing and invasion of MDA-MB-231 and SK-BR3 cells were determined. The impact of HAE treatment on spontaneous and TGF-β1-promoted EMT and the nuclear factor (NF)-κB signaling in breast cancer cells was examined by quantitative RT-PCR and western blotting.

RESULTS

Treatment with HAE at varying concentrations did not change the viability of breast cancer cells. However, HAE at 0.25 or 0.5 mg/mL significantly reduced the number and size of formed mammospheres, and inhibited spontaneous and TGF-β1-enhanced wound healing, invasion and EMT in MDA-MB-231 and SK-BR3 cells in a dose-dependent manner. TGF-β1 treatment significantly decreased IκBα expression and increased NF-kBp65 phosphorylation in breast cancer cells, indicating that TGF-β1 enhanced NF-κB signaling. In contrast, HAE treatment attenuated the spontaneous and TGF-β1-enhanced NF-κB signaling in breast cancer cells.

CONCLUSION

Our data indicated that HAE inhibited the self-renewal of stem-like cells and spontaneous and TGF-β1-enhanced wound healing, invasion and EMT in breast cancer cells by attenuating the NF-κB signaling in vitro.

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.

Identification of the miRNA-mRNA regulatory network of antler growth centers

Antler growth is a unique event compared to other growth and development processes in mammals. Antlers grow extremely fast during the rapid growth stage when growth rate peaks at 2 cm per day. Antler growth is driven by a specific endochondral ossification process in the growth center that is in the distal region of the antler tip. In this study, we used state-of-art RNA-seq technology to analyze the expression profiles of mRNAs and miRNAs during antler growth. Our results indicated that the expression levels of multiple genes involved in chondrogenesis and endochondral ossification, including Fn1, Sox9, Col2a1, Acan, Col9a1, Col11a1, Hapln1, Wwp2, Fgfr3, Comp, Sp7 and Ihh, were significantly increased at the rapid growth stage. Our results also indicated that there were multiple differentially expressed miRNAs interacting with differentially expressed genes with opposite expression patterns. Furthermore, some of the miRNAs, including miR-3072-5p, miR-1600, miR-34-5p, miR-6889-5p and miR-6729-5p, simultaneously interacted with and controlled multiple genes involved in the process of chondrogenesis and endochondral ossification. Therefore, we established a miRNA-mRNA regulatory network by identifying miRNAs and their target genes that were differentially expressed in the antler growth centers by comparing the rapid growth stage and the initial growth stage.

Compositional analysis of the glycosaminoglycan family in velvet antlers of Sika deer (Cervus nippon) at different growing stages

Glycosaminoglycans (GAG) from the velvet antlers of Sika deer (Cervus nippon) at the different growing stages (Fukurozuno, Anshi, and Santajo) of bred and wild deer were isolated and their concentrations and sulfation patterns were analyzed. GAG were digested with chondroitinase ABC, ACI, heparinase-I and -III, and keratanase-II into the corresponding repeating disaccharides of chondroitin sulfate (CS), dermatan sulfate (DS), hyaluronan, heparan sulfate (HS), and keratan sulfate. Cartilaginous tissues contained CS-DS at high concentrations with an almost equal ratio of 4- and 6-sulfates, while 4-sulfate-type CS-DS predominantly occupied ossified tissues, but at low concentrations. High O- and N-sulfation degrees of HS correspond to high ossification. Dynamic quantitative changes in CS-DS and compositional changes in CS-DS and HS were closely associated with the mineralization of deer antlers.

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.

Identifying deer antler uhrf1 proliferation and s100a10 mineralization genes using comparative RNA-seq

BACKGROUND

Deer antlers are bony structures that re-grow at very high rates, making them an attractive model for studying rapid bone regeneration.

METHODS

To identify the genes that are involved in this fast pace of bone growth, an in vitro RNA-seq model that paralleled the sharp differences in bone growth between deer antlers and humans was established. Subsequently, RNA-seq (> 60 million reads per library) was used to compare transcriptomic profiles. Uniquely expressed deer antler proliferation as well as mineralization genes were identified via a combination of differential gene expression and subtraction analysis. Thereafter, the physiological relevance as well as contributions of these identified genes were determined by immunofluorescence, gene overexpression, and gene knockdown studies.

RESULTS

Cell characterization studies showed that in vitro-cultured deer antler-derived reserve mesenchyme (RM) cells exhibited high osteogenic capabilities and cell surface markers similar to in vivo counterparts. Under identical culture conditions, deer antler RM cells proliferated faster (8.6-11.7-fold increase in cell numbers) and exhibited increased osteogenic differentiation (17.4-fold increase in calcium mineralization) compared to human mesenchymal stem cells (hMSCs), paralleling in vivo conditions. Comparative RNA-seq identified 40 and 91 previously unknown and uniquely expressed fallow deer (FD) proliferation and mineralization genes, respectively, including uhrf1 and s100a10. Immunofluorescence studies showed that uhrf1 and s100a10 were expressed in regenerating deer antlers while gene overexpression and gene knockdown studies demonstrated the proliferation contributions of uhrf1 and mineralization capabilities of s100a10.

CONCLUSION

Using a simple, in vitro comparative RNA-seq approach, novel genes pertinent to fast bony antler regeneration were identified and their proliferative/osteogenic function was verified via gene overexpression, knockdown, and immunostaining. This combinatorial approach may be applicable to discover unique gene contributions between any two organisms for a given phenomenon-of-interest.

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.

Barium concentration in cast roe deer antlers related to air pollution caused by burning of barium-enriched coals in southern Poland

Concentrations of Ba, Zn, Pb, Fe, and Mn were determined by atomic absorption spectroscopy in freshly cast antlers from male roe deer of different ages (2 to 4 years old and older than 4 years) collected in Balin near Chrzanów and in the vicinity of Żywiec, S Poland. Barium content ranged from 124 to 196 ppm (mean 165 ppm) in the Balin 12 samples and from 207 to 351 ppm (mean 287 ppm) in 3 antlers from Żywiec. The concentration of Ba was comparable to that of Zn (134-275 ppm, mean 169 ppm). Elevated concentrations of Ba in antlers most probably originated from direct uptake of airborne barite nanocrystals through the respiratory system and/or by digestion of barite-rich dust particles deposited on plants. Burning of Ba-enriched coals is regarded as the principal source of Ba in the investigated areas inhabited by roe deer. Increased concentrations of Ba in antlers from the Żywiec area compared to Balin reflect particularly high air pollution caused by coal-burning mostly for domestic purposes combined with an unfavorable topography that impedes efficient air circulation.

Species cross-amplification, identification and genetic variation of 17 species of deer (Cervidae) with microsatellite and mitochondrial DNA from antlers

Strong anthropogenic impact has caused 28 of the currently recognized 55 species of deer (Cervidae) to be listed on the IUCN Red List. Particular threats to vulnerable species include habitat deterioration and hybridization with alien, introduced species. The scarcity of many species has severely hampered genetic analyses of their populations, including the detection of loci for cross-species amplification. Because deer antlers are shed and re-grown annually, antlers offer the possibility for non-invasive genetic sampling of large individual numbers, and may provide material for reference genotyping from historical samples stored in zoos, museums and trophy collections of rare and extinct species/populations. In this paper, we report cross-species amplification of 19 nuclear microsatellite loci and the amplification of 16S mtDNA for barcoding from nearly a third of all deer species worldwide based on high quality DNA extracted from antler bone up to 40 years old. Phylogenetic analysis based on mtDNA of seventeen species and five subspecies corroborate previously published phylogenetic data, thus confirming the specific resolution of the DNA extraction methodology.

Characteristics of MIC-1 antlerogenic stem cells and their effect on hair growth in rabbits

AIM

We characterized growth factors produced by MIC-1 antlerogenic stem cells and attempted to apply those cells to stimulate hair growth in rabbits.

MATERIALS AND METHODS

We evaluated the gene and protein expression of growth factors by immunocytochemical and molecular biology techniques in MIC-1 cells. An animal model was used to assess the effects of xenogenous stem cells on hair growth. In the experimental group, rabbits were intradermally injected with MIC-1 stem cells, whereas the control group rabbits were given vehicle-only. After 1, 2 and 4 weeks, skin specimen were collected for histological and immunohistochemical tests.

RESULTS

MIC-1 antlerogenic stem cells express growth factors, as confirmed at the mRNA and protein levels. Histological and immunohistochemical analysis demonstrated an increase in the number of hair follicles, as well as the amount of secondary hair in the follicles, without an immune response in animals injected intradermally with MIC-1 cells, compared to animals receiving vehicle-alone.

CONCLUSION

MIC-1 cells accelerated hair growth in rabbits due to the activation of cells responsible for the regulation of the hair growth cycle through growth factors. Additionally, the xenogenous cell implant did not induce immune response.

[Effects of pilose antler polypeptide on the glycosaminoglycan and type II collagen in experimental knee osteoarthritis]

OBJECTIVE

To observe the influence of Pilose antler polypeptide on the glycosaminoglycan and type II collagen in the articular cartilage in experimental knee osteoarthritis.

METHODS

Totally 64 New Zealand white rabbits of 6 months old were randomly divided into 2 groups:normal group (n = 8) and model group (n = 56). Model group was surgically induced into osteoarthritis model by method of Hulth. After successful modeling, the rabbits of model group were further divided into 2 groups: Pilose antler polypeptide-treatment group and control group, 24 rabbits in each group. Pilose antler polypeptide-treatment group received 0.5 ml intra-articular injection of Pilose antler polypeptide dilution liquid once in per 2 days for 30 days, while control group received 0.5 ml intra-articular injection of physiological saline. On days 7, 15 and 30 after intervention, articular cartilage samples were collected respectively. The content of glycosaminoglycan in articular cartilage was observed by toluidine blue staining and the expression of type II collagen in cartilage matrix was detected by immunohistochemical staining.

RESULTS

Along with the prolonging of time, the content of glycosaminoglycan and type II collagen in cartilage matrix of the Pilose antler polypeptide-treatment group and control group decreased gradually. On days 7, 15 and 30 after intervention, integrated optical density of the type II collagen positive area in cartilage matrix of the Pilose antler polypeptide-treatment group were (312.06 +/- 14.12), (273.31 +/- 12.42) and (248.34 +/- 10.41), which had statistically significant differences. Integrated optical density of the type II collagen positive area in cartilage matrix of the control group were (253.47 +/- 15.53), (215.67 +/- 9.72) and (160.01 +/- 13.23), which had statistically significant differences. At the same period, integrated optical density of the type II collagen positive area in cartilage matrix of the Pilose antler polypeptide-treatment group was higher than that of control group, which had statistically significant difference.

CONCLUSION

Pilose antler polypeptide can inhibit reduction of the glycosaminoglycan and type II collagen in cartilage matrix and delay the degeneration of articular cartilage.

Proteomes and signalling pathways of antler stem cells

As the only known example of complete organ regeneration in mammals, deer antler in the growing or velvet phase is of major interest in developmental biology. This regeneration event initiates from self-renewing antler stem cells that exhibit pluripotency. At present, it remains unclear how the activation and quiescence of antler stem cells are regulated. Therefore, in the present study proteins that were differentially expressed between the antler stem cells and somatic cells (facial periosteum) were identified by a gel-based proteomic technique, and analysed using Ingenuity Pathway Analysis software. Several molecular pathways (PI3K/Akt, ERK/MAPK, p38 MAPK, etc.) were found to be activated during proliferation. Also expressed were the transcription factors POU5F1, SOX2, NANOG and MYC, which are key markers of embryonic stem cells. Expression of these proteins was confirmed in both cultured cells and fresh tissues by Western blot analysis. Therefore, the molecular pathways and transcription factors identified in the current study are common to embryonic and adult stem cells. However, expression of embryonic stem cell transcription factors would suggest that antler stem cells are, potentially, an intermediary stem cell type between embryonic and the more specialized tissue-specific stem cells like those residing in muscle, fat or from a hematopoietic origin. The retention of this embryonic, pluripotent lineage may be of fundamental importance for the subsequent regenerative capacity of antlers.

Combined genomic-metabolomic approach for the differentiation of geographical origins of natural products: deer antlers as an example

The correct identification of the geographical origin of deer antlers is essential to quality control, as its positive physiological effects correlate with chemical components. In this study, we applied both genomics and metabolomics to the origin-identification of 101 samples from Canada, New Zealand, and Korea. The genomics identified deer species in each country but failed to categorize all the samples, due to the presence of identical species in different countries. For identical species, NMR-based metabolomics gave clean separations, compounds specific to each country were identified, and the validity was confirmed by prediction analysis. As the genomics provided unambiguous read-outs for different species, and the metabolomics cleanly distinguished among identical species from different countries, their combined use could be a robust method for origin-identification even in difficult cases. We believe the method to be generally applicable to many herbal medicinal products for which various species are grown internationally.

Antlers of Cervus elaphus as biomonitors of ⁹⁰Sr in the environment

Adequate radioprotection of the environment requires the identification of biomonitors sensitive to the variation of its radionuclide content. Due to the chemical similarities between calcium and strontium, calcified tissues of mammals are considered to be good ⁹⁰Sr biomonitors. This work considered Cervus elaphus antlers which, being shed annually, can give information about the importance of radiostrontium contamination in an ecosystem in the time period required for the growth of the antler. The samples were collected at various points of W and SW Spain. The mean value of their ⁹⁰Sr content was (70 ± 43 (S.D.)) Bq/kg d.w., range (16-218) Bq/kg d.w., and the radionuclide was evenly distributed in the different parts of the antler. There was a good correlation between the antlers' ⁹⁰Sr content and the ⁹⁰Sr deposited in the soil. The antlers' content of ²²⁶Ra (from the natural uranium series) and the contents of some stable elements (Ca, Mg, Sr, and K) were also determined. The values for these stable elements were practically constant in the analyzed samples, and the concentrations measured decreased in the following order: Ca » Mg > K > Sr » ⁹⁰Sr > ²²⁶Ra.

Iodine distribution in the environment as a limiting factor for roe deer antler development

The iodine-containing hormones produced by the thyroid gland play a role in the complex neuro-hormonal regulation of antler development. The proper function of the thyroid depends on the adequate iodine supply of the organism, which is directly related to the iodine content of food and drinking water. The purpose of this study was to explore the connection between the iodine content of the water base, which has a strong correlation with the iodine concentration of environmental components available to animals, and the antler weight of roe deer (Capreolus capreolus) shot in Hungarian hunting areas. Using a general linear model, controlling for the collective effects of other environmental factors (deer population density, harvest rate, land use, and soil fertility information), the iodine content of the water base explained 51.4% of the total variance of antler weights. The results suggest that antler weights increase with increasing iodine concentration regardless of other factors; thus, the environmental iodine distribution can be a limiting factor suppressing roe deer performance assessed here as antler weight. Further experimental studies of controlled iodine uptake are needed to define the exact physiological iodine requirements of roe deer bucks.

Stimulation of osteoblastic differentiation and mineralization in MC3T3-E1 cells by antler and fermented antler using Cordyceps militaris

ETHNOPHARMACOLOGICAL RELEVANCE

For thousands of years antlers have been used in Asian countries to promote rapid healing, treat weight loss, slow growth in children, strengthen weak bones, and alleviate cold hands and feet.

AIM OF THE STUDY

The present study was performed to examine the effect of fermentation on the ability of antler to act as a stimulator of bone growth.

MATERIALS AND METHODS

This study used pre-osteoblast MC3T3-E1 cells to examine factors related to bone growth, such as cell proliferation, production of alkaline phosphatase (ALP), and deposition of extracellular matrix proteins (e.g., collagens, osteonectin, bone sialoprotein (BSP)), via the treatment of non-fermented and fermented antler.

RESULTS

Antler fermentation using Cordyceps militaris was carried out at 25°C for seven days. The total content of sugar, sialic acid, and protein increased with fermentation time. Cell proliferation was greater in the fermented antler- (FA-) treated groups than in the NFA- (non-fermented antler-) treated groups, in which proliferation increased significantly up to 137% of the basal value. Significant increases in mRNA expression and ALP activity were found at FA concentrations of 50-100 μg/ml; at 100 μg/ml the activity had increased 119% compared to the control activity. For NFA and FA the expression levels of type I collagen mRNA significantly increased in a dose-dependent manner at all treatment doses. However, significant differences between the antler groups were not observed. Mineralization significantly increased by NFA and FA treatment to 183% and 241%, respectively, when compared to colostrum, as a positive control (165%).

CONCLUSIONS

Antler treatment increased the proliferation of osteoblasts and bone matrix proteins, such as type I collagen and BSP. Antler fermented with Cordyceps militaris showed enhanced activity, and its stimulatory effects on cell proliferation and ALP production were greater than those of NFA. We surmise that these increases in activity were related to increased sialic acid content. Therefore, the results of this study suggest that the physiological effects of antler, including bone growth, may be increased through the fermentation process.

Historical biomonitoring of fluoride pollution by determining fluoride contents in roe deer (Capreolus capreolus L.) antlers and mandibles in the vicinity of the largest Slovene thermal power plant

Roe deer antlers/mandibles are a useful tool for determination of ambient fluoride pollution. Antlers have a well-defined annual cycle of growth, therefore they represent a natural standardisation of samples during winter months. On the contrary, mandibles accumulate fluorides during the whole life of an organism, thus they reflect aggregated effect of fluoride pollution trough the life-span of an organism. Both tissues are easily available; mandibles are often systematically collected with the purpose of cognitive management and control, and antlers could be gathered from private well-dated hunters' collections. Considering these benefits, fluoride contents were measured in 141 antlers (period 1960-2007) and 220 mandibles (period 1997-2009) of roe deer, shot in the vicinity of the largest Slovene Thermal Power Plant of Šoštanj (ŠTPP) as one of the major sources of fluorides in Slovenia. Fluoride contents in antlers significantly differed among age categories, and ranged from 110 to 1210 mg/kg in yearlings, 130 to 2340 mg/kg in young adults, and 250 to 2590 mg/kg in older adults, respectively. Fluoride levels in mandibles were also significantly different among age categories, and ranged from 30.0 to 227 mg/kg in fawns, 33.8 to 383 mg/kg in yearlings, and 61.5 to 1020 mg/kg in adults, respectively. Comparison of these results with previously reported fluoride contents in antlers and mandibles of roe deer from different areas of Europe revealed that the study area has never been extensively contaminated with fluorides. Moreover, trends of fluoride contents in both tissues confirmed a significant decrease of fluoride pollution in the area after the years 1995 and 2000, when flue-gas cleaning devices were constructed on the ŠTPP. Indeed, highly positive correlations between annual emissions from the ŠTPP and mean annual fluoride contents in antlers/mandibles confirmed that both tissues may be a useful tool for assessing temporal trends in ambient fluoride pollution.

[Enzymatic hydrolysis of antler and properties of hydrolysates]

Lyophylized antler powder was hydrolyzed by pepsin and trypsin separately and also simultaneously to give hydrolysates with special physical activities. Complete hydrolysis peptides with MW lower than 1 x 10(3) were collected for assay of angiotensin I-converting enzyme (ACE) inhibitory activity, antioxidant activity and proliferative activity toward UMR-106 osteoblast cells. The results of the experiments revealed that all hydrolysates exhibited potent hydroxyl radical scavenging activity with an IC50 value less than 1 mg/ml which was much lower than the value of 5.5 g x L(-1) for vitamin C. The peptic and peptic tryptic hydrolysates demonstrated strong angiotensin I-converting enzyme (ACE) inhibitory activity. The tryptic hydrolysate increased the proliferation of the UMR-106 cells by 73.43%. The results verified the traditional use of antler in bone-strengthening, anti-aging. The exploratory studies on the ACE inhibitory activity of antler hydrolysates indicated that the hydrolysates might be potentially useful in prevention and treatment of hypertension. Further purification of peptides contributing to the antioxidant activity, angiotensin I-converting enzyme-inhibitory activity and proliferative activity toward osteoblasts from antler hydrolysates is warranted.

[Protective effects of peptides from velvet antler of Cervus nippon on acute ischemic myocardial injury in rats]

OBJECTIVE

To investigate the cardioprotective effects of the peptides from the velvet antler (VAP) of Cervus nippon on acute ischemic myocardial injury in rats and its underlying mechanisms.

METHOD

The model rats of myocardial ischemia injury (MI) was produced by ligating the left anterior descending (LAD) branch of the coronary artery of rats. The rats were divided randomly into six groups: sham-operated group; ischemic myocardial injury (MI) model group; diltiazem hydrochloride 1 mg x kg(-1) group; VAP 30 mg x kg(-1) group; VAP 60 mg x kg(-1) group; VAP 120 mg x kg(-1) group. VAP or diltiazem hydrochloride (calcium-antagonist) was injected into the tail vein of each of the experimental rats 12 h and 23 h respectively after left anterior descending (LAD) occlusion. The same volume of saline was administered into the sham-operated group and MI model group. The ischemic size, ST elevation, serum levels of creatine kinase (CK), lactate dehydrogenase (LDH), aspartate transaminase (AST), superoxide dismutase (SOD), malondialdehyde (MDA), and levels of SOD, MDA in myocardial tissue were measured in the rats at 24 h after LAD occlusion.

RESULT

The ischemic risk area ratio was 34.52 +/- 8.69% in the MI control group. Treatment of VAP at doses of 60 and 120 mg x kg(-1) resulted in reductions in the infarct size of (21.67 +/- 5.19)% and (19.56 +/- 9.15)% (P < 0.05), respectively. Treatment with VAP at doses of 30, 60 and 120 mg x kg(-1) significantly decreased ST elevation (0.28 +/- 0.03, 0.21 +/- 0.03, 0.16 +/- 0.02, 0.15 +/- 0.02) mV (all P < 0.01), compared with the MI control rats (0.41 +/- 0.05) mV. VAP also significantly decreased levels of CK, LDH, AST, MDA in serum and myocardial tissue, increase SOD activity in serum and myocardial tissue in MI rats.

CONCLUSION

VAP exerts significant cardioprotective effects against acute ischemic myocardial injury in rats, likely through its antioxidant and anti-lipid peroxidation properties.

Testosterone, but not IGF-1, LH, prolactin or cortisol, may serve as antler-stimulating hormone in red deer stags (Cervus elaphus)

The role of androgens and insulin-like growth factor 1 (IGF-1) in antler growth has been disputed. We predicted that the secretory of IGF-1 may be associated with an acceleration of body growth rather than with antler growth. Furthermore we anticipated a relationship between the increase of testosterone and the progress of antler growth. If IGF-1 is involved in the stimulation of antler growth, this should be more obvious in young than in mature stags. Eight two-year-old red deer stags (Cervus elaphus), and twelve adult red deer stags were blood sampled and the length of their velvet antlers was measured in one-week intervals during the period of antler growth. Concentrations of testosterone, cortisol, IGF-1, luteinizing hormone (LH), and prolactin were determined in plasma by enzyme immunoassay or radioimmunoassay. Antler growth per day was primarily dependent on changes in testosterone concentration per day in both groups of stags. As expected, only in two-year-old stags we detected a possible role of IGF-1 in the antler growth regulation, but that was not in agreement with previously published studies. Nevertheless, this effect was still utilized in interaction with testosterone. In addition to total antler length, only concentrations of testosterone and LH were significantly higher in adult males in comparison to two-year-old males. Our present results lead us to conclude that it is not IGF-1 but testosterone which is responsible for the intensity of antler growth in subadult and adult red deer stags.

Expression and localization of insulin-like growth factor-I in four parts of the red deer antler

The expression and localization of insulin-like growth factor-I (IGF-I) in the four parts (tip, upper, mid and base) of the red deer antler has been extensively investigated. We used reverse transcriptase polymerase chain reaction (RT-PCR) and real-time reverse transcriptase polymerase chain reaction (real time RT-PCR), in situ hybridization, immunohistochemistry and Western blot techniques to localize IGF-I messenger ribonucleic acid (mRNA) and IGF-I peptide in the four parts of the antler. The specific sequence encoding IGF-I was detected by RT-PCR in all of the four specimens, and the 395 bp IGF-I sequence from the red deer antler was shown to have very high homology with human, goat and mouse IGF-I. In situ hybridization and immunohistochemistry results demonstrated that the expression of IGF-I occurred in chondrocytes and osteoblasts in the tip and upper parts of the antler. However, IGF-I was only detectable in osteoblasts around the bone in the mid and base parts. There were significant differences in the intensity of the signal obtained with the IGF-I probe in the tip, upper, mid and base tissues. The Western blot analysis also provided evidence that IGF-I expression was localized differentially in the four parts of the deer antler. This study indicates that antler tissue is an essential part of the IGF system, which is involved in the regulation of the growth of red deer antlers. The specific expression of IGF-I in the four parts of the deer antler suggests that the IGF-I molecule is present at significantly different levels throughout the deer antler development and regeneration processes. Localization of IGF-I in chondrocytes and osteoblasts suggests that IGF-I may play an important role in cartilage and bone formation. In addition, it may have a variety of biophysical effects that influence the rapid growth of deer antlers.

The distribution of the growth factors FGF-2 and VEGF, and their receptors, in growing red deer antler

The cellular distributions of the growth factors FGF-2 and VEGF, and their receptors FGFR1, FGFR2 and FGFR3, and VEGFR-2 respectively, were visualized by immunohistochemistry and light microscopy in sections of growing red deer antler. Both of these signalling systems were widely expressed in the integument and osteocartilaginous compartments. FGF-2 was found in the same cells as all three FGFRs, indicating that FGF signalling may be principally autocrine. The patterns of labelling for VEGF and its receptor were similar to those seen for FGF-2 and FGFR-3, in both compartments. Our data are consistent with the findings of others in suggesting that FGF-2 induces expression of VEGF, to stimulate and maintain high rates of neovascularisation and angiogenesis, thereby providing nutrients to both velvet and bone as they rapidly grow and develop. The presence of FGF and VEGF and their receptors in epithelial cells suggests that these signalling systems play a role in skin development, raising the possibility that one or both may be involved in the close coupling of the coordinated growth of the integument and osteocartilage of antler, a process which is poorly understood at present.

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

Deer antlers are the only mammalian organs that can fully regenerate each year. During their growth phase, antlers of red deer extend at a rate of approximately 10 mm/day, a growth rate matched by the antler nerves. It was demonstrated in a previous study that extracts from deer velvet antler can promote neurite outgrowth from neural explants, suggesting a possible role for Nerve Growth Factor (NGF) in antler innervation. Here we showed using the techniques of Northern blot analysis, denervation, immunohistochemistry and in situ hybridization that NGF mRNA was expressed in the regenerating antler, principally in the smooth muscle of the arteries and arterioles of the growing antler tip. Regenerating axons followed the route of the major blood vessels, located at the interface between the dermis and the reserve mesenchyme of the antler. Denervation experiments suggested a causal relationship exists between NGF mRNA expression in arterial smooth muscle and sensory axons in the antler tip. We hypothesize that NGF expressed in the smooth muscle of the arteries and arterioles promotes and maintains antler angiogenesis and this role positions NGF ahead of axons during antler growth. As a result, NGF can serve a second role, attracting sensory axons into the antler, and thus it can provide a guidance cue to define the nerve track. This would explain the phenomenon whereby re-innervation of the regenerating antler follows vascular ingrowth. The annual growth of deer antler presents a unique opportunity to better understand the factors involved in rapid nerve regeneration.

Gene expression dynamics in deer antler: mesenchymal differentiation toward chondrogenesis

Annual re-growth of deer antler represents a unique example of complete organ regeneration. Because antler mesenchymal cells retain their embryonic capacity to develop into cartilage or bone, studying antler development provides a natural system to follow gene expression changes during mesenchymal differentiation toward chondrogenic/osteogenic lineage. To identify novel genes involved either in early events of mesenchymal cell specialization or in robust bone development, we have introduced a 3 K heterologous microarray set-up (deer cDNA versus mouse template). Fifteen genes were differentially expressed; genes for housekeeping, regulatory functions (components of different signaling pathways, including FGF, TGFbeta, Wnt), and genes encoding members of the Polycomb group were represented. Expression dynamics for genes are visualized by an expression logo. The expression profile of the gene C21orf70 of unknown function is described along with the effects when over-expressed; furthermore the nuclear localization of the cognate protein is shown. In this report, we demonstrate the particular advantage of the velvet antler model in bone research for: (1) identification of mesenchymal and precartilaginous genes and (2) targeting genes upregulated in robust cartilage development.

Identification of differentially expressed genes in the developing antler of red deer Cervus elaphus

Understanding the molecular mechanisms underlying bone development is a fundamental and fascinating problem in developmental biology, with significant medical implications. Here, we have identified the expression patterns for 36 genes that were characteristic or dominant in the consecutive cell differentiation zones (mesenchyme, precartilage, cartilage) of the tip section of the developing velvet antler of red deer Cervus elaphus. Two major functional groups of these genes clearly outlined: six genes linked to high metabolic demand and other five to tumor biology. Our study demonstrates the advantages of the antler as a source of mesenchymal markers, for distinguishing precartilage and cartilage by different gene expression patterns and for identifying genes involved in the robust bone development, a striking feature of the growing antler. Putative roles for "antler" genes that encode alpha-tropomyosine (tpm1), transgelin (tagln), annexin 2 (anxa2), phosphatidylethanolamine-binding protein (pebp) and apolipoprotein D (apoD) in intense but still controlled tissue proliferation are discussed.

Metabolomic differentiation of deer antlers of various origins by 1H NMR spectrometry and principal components analysis

The metabolomic analysis of various types of deer antler was performed by 1H NMR spectrometry and principal components analysis (PCA). The PCA of the 1H NMR spectra of the aqueous fractions allowed a clear discrimination between antler samples according to their origins by the first three principal components (PC1, PC2, and PC3), which cumulatively accounted for 93.5% of the variation in all variables. In particular, the score plots by the combination of PC1 and PC3 allowed an excellent separation of the antler samples. In addition, the major peaks in 1H NMR spectra contributing to the discrimination were assigned to lactate, alanine, acetic acid, choline, glycine, valine, tyrosine, and phenylalanine. This metabolomic-analysis-based method allows various types of deer antler to be efficiently differentiated without any pre-purification steps.

Distribution of EGF and its receptor in growing red deer antler

Autografts of the osteogenic part of early antler buds placed elsewhere on the skull have been shown by others to give rise to an antler at the site of grafting. This antler becomes covered in velvet skin, is shed at the end of the growing season and will regrow the following year. Thus, it can be concluded that the nature of antler velvet skin is primarily determined by the underlying osteogenic antler tissue to which it is attached. We hypothesise that a paracrine mechanism operates here and is central to communication between the antler osseous compartment and the integument. A signalling system comprising epidermal growth factor (EGF) and its receptor (EGFR) is known to be expressed in osteogenic cells and to play an important role in skin development and growth. This system may therefore play a significant role in determining the nature and speed of growth of velvet skin via paracrine signalling from osteogenic tissue. We have used bright-field microscope immunohistochemistry to determine the distribution of EGF and its receptor in developing red deer antler osseous compartment and integument. EGF was localized throughout the epidermis and epidermal appendages, in cells of the mesenchyme, in chondrocytes, and in cells of the osteoblastic lineage, including osteoprogenitor cells, osteoblasts and osteocytes. There was strong evidence supporting nuclear and nucleolar staining in sebaceous glands and in keratinocytes. The EGFR was similarly expressed in mesenchyme, chondrocytes and osteoblasts. In skin, the distribution of the EGFR was more localized, being expressed strongly in the deeper cells of the epidermis but not in superficial layers, and was absent from nuclei of cells of the epidermis and its appendages. We conclude that this signalling system is widely distributed in growing antler in a manner which suggests it is predominantly autocrine. No clear-cut evidence for paracrine signalling pathways for this system in either integument or osseous compartments was found. The pattern of distribution of the EGFR in the integument was similar to that seen by others in adult human skin. By contrast, in developing antler osseocartilage, the patterns of distribution were similar to those seen in rodent fetal bone. We conclude that antler consists of rapidly growing fetal osseocartilage overlayed by mature velvet.

Characterization of heparan sulfate from the unossified antler of Cervus elaphus

The antler is the most rapidly growing tissue in the animal kingdom. According to previous reports, antler glycosaminoglycans (GAGs) consist of all kinds GAGs except for heparan sulfate (HS). Chondroitin sulfate is the major antler GAG component comprising 88% of the total uronic acid content. In the current study, we have isolated HS from antler for the first time and characterized it based on both NMR spectroscopy and disaccharide composition analysis. Antler GAGs were isolated by protease treatment and followed by cetylpyridinium chloride precipitation. The sensitivity of antler GAGs to heparin lyase III showed that this sample contained heparan sulfate. After incubation of antler GAGs with chondroitin lyase ABC, the HS-containing fraction was recovered by ethanol precipitation. The composition of HS disaccharides in this fraction was determined by its complete depolymerization with a mixture of heparin lyase I, II, and III and analysis of the resulting disaccharides by the reversed-phase (RP) ion pairing-HPLC, monitored by the fluorescence detection using 2-cyanoacetamide as a post-column labeling reagent. Eight unsaturated disaccharides (DeltaUA-GlcNAc, DeltaUA-GlcNS, DeltaUA-GlcNAc6S, DeltaUA2S-GlcNAc, DeltaUA-GlcNS6S, DeltaUA2S-GlcNS, DeltaUA2S-GlcNAc6S, DeltaUA2S-GlcNS6S) were produced from antler HS by digestion with the mixture of heparin lyases. The total content of 2-O-sulfo disaccharide units in antler HS was higher than that of heparan sulfate from most other animal sources.

Proteome analysis of red deer antlers

Deer antlers are the only mammalian organs capable of repeated regeneration. Although antlers are known to develop from pedicles, which arise from antlerogenic cells of cranial periosteum, their developmental process is not fully elucidated. For example, while endocrine and environmental factors influence the antler development, it is still unclear which signaling pathways are involved in the transduction of such stimuli. To study the developmental process of antlers and identify proteins functioning in their growth, we have established proteome maps of red deer (Cervus elaphus) antlers. With two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionization mass spectrometry, we analyzed more than 800 protein spots and identified approximately 130 individual proteins derived from the growing tip of antlers. The overall profile of the antler proteome was dissimilar to those of other types of tissue. Also comparison of proteomes derived from proximal bony tissue and the growing tip of antlers revealed substantial differences. Moreover several cell growth or signaling-related proteins are expressed exclusively in the growing tip, suggesting that these proteins function in the growth and differentiation of antlers. Currently, using the antler proteome maps, we are actively searching for the regulatory factor(s) that may control the antler development.

Expression of PTHrP and the PTH/PTHrP receptor in growing red deer antler

Antler growth is highly co-ordinated, so that trabecular bone and antler skin (velvet) develop together, at a rapid rate and in a manner reminiscent of their development in the fetus. Parathyroid hormone-related peptide (PTHrP) is expressed in both bone and skin, and is therefore a candidate to effect co-ordination between these tissues. The aim of this study was to localize the expression of PTHrP and its principal receptor, the parathyroid hormone/parathyroid hormone-related peptide receptor (PTH/PTHrPR), in antler ("spiker") of one-year-old red deer. Using immunohistochemistry and in situ hybridization, intense and overlapping expression of PTHrP and its receptor was seen in developing osseocartilaginous structures and in the underlying layers of velvet epidermis. PTHrP was located on both the cell surface and within the nuclei. Our results strongly suggest that PTHrP, acting via the PTH/PTHrPR and possibly other intracrine mechanisms, plays a central role in the co-ordinated regulation of cell division and differentiation of developing antler bone and skin.

Recapitulation of the parathyroid hormone-related peptide-Indian hedgehog pathway in the regenerating deer antler

Parathyroid hormone (PTH)-related peptide (PTHrP) and the PTH/PTHrP receptor (PPR) play an essential role in controlling growth plate development. The aim of the present study was to use the deer antler as a model to determine whether PTHrP and PPR may also have a function in regulating cartilage and bone regeneration in an adult mammal. Antlers are the only mammalian appendages that are able to undergo repeated cycles of regeneration, and their growth from a blastema involves a modified endochondral process. Immunohistochemistry was used to establish sites of localization of PTHrP and PPR in antlers at different stages of development. The pattern of Indian Hedgehog (IHH) and transforming growth factor-beta1 (TGF beta1) distribution was also investigated, because PTHrP expression in the developing limb is regulated by IHH and during embryonic growth plate formation TGF beta1 acts upstream of PTHrP to regulate the rate of chondrocyte differentiation. In the antler blastema (<10 days of development), PTHrP, PPR, and TGF beta1 were localized in epidermis, dermis, regenerating epithelium, and in mesenchymal cells but IHH expression was not detected. In the rapidly growing antler (weeks 4-8 of development), PTHrP, PPR, and TGF beta1 were localized in skin, perichondrium, undifferentiated mesenchyme, recently differentiated chondrocytes, and in perivascular cells in cartilage but not in fully differentiated hyperytrophic chondrocytes. IHH was restricted to recently differentiated chondrocytes and to perivascular cells in cartilage. In mineralized cartilage and bone, PTHrP, PPR, IHH, and TGF beta1 were immunolocalized in perivascular cells and differentiated osteoblasts. PTHrP and PPR were also present in the periosteum. TGF beta1 in vitro stimulated PTHrP synthesis by cells from blastema, perichondrium, and cartilage. The findings of this study suggest that molecules which regulate embryonic skeletal development and postnatal epiphyseal growth may also control blastema formation, chondrogenesis, and bone formation in the regenerating deer antler. This finding is further evidence that developmental signaling pathways are recapitulated during adult mammalian bone regeneration.

Histological studies of bone formation during pedicle restoration and early antler regeneration in roe deer and fallow deer

The purpose of the present study was to examine the process of bone formation in the regenerating cranial appendages of roe deer (Capreolus capreolus) and fallow deer (Dama dama) during the early postcasting period. After the antlers are cast, osteoclastic and osteoblastic activities lead to a smoothing of the pedicle's separation surface, a strengthening of the pedicle bone, and a partial restoration of the distal pedicle portion that was lost along with the cast antler. Initially, bone formation occurs by intramembranous ossification, but early during the regeneration process cartilage is formed at the tips of the cranial appendages, and is subsequently replaced by bone in a process of endochodral ossification. Shortly after the antlers are cast, the cambium layer of the periosteum in the distal pedicle is markedly enlarged, which suggests that the periosteum serves as a cell source for the bone-forming tissue covering the exposed pedicle bone. The histological findings of our study are consistent with the view that the bony component of the regenerating cranial appendages of deer is largely derived from the pedicle periosteum. Based on findings in other bone systems, we speculate that stem cells that can undergo both osteogenic and chondrogenic differentiation are present in the pedicle periosteum. The early onset of chondrogenesis in the regeneration process is regarded as an adaptation to the necessity of producing a huge volume of bone within a short period. This parallels the situation in other cases of chondrogenesis in membrane bones.

Nuclear localization of type I parathyroid hormone/parathyroid hormone-related protein receptors in deer antler osteoclasts: evidence for parathyroid hormone-related protein and receptor activator of NF-kappaB-dependent effects on osteoclast formation in regenerating mammalian bone

Parathyroid hormone-related protein (PTHrP) is not required for osteoclastogenesis during embryonic development; however, after birth it has been shown to regulate osteoclast formation during tooth eruption. Our study explores the hypothesis that PTHrP also may regulate osteoclast differentiation in the regenerating skeletal tissues of deer antlers, bones capable of complete regeneration. Osteoclast-like multinucleated cells (MNCs) formed spontaneously in micromass cultures derived from antler cartilage and these cells had the phenotypic characteristics of osteoclasts. PTHrP and receptor activator of NF-kappaB ligand (RANKL) stimulated antler osteoclast formation although the effect of RANKL was less marked than that of PTHrP. The addition of osteoprotegerin (OPG) only partially decreased (by approximately 65%) the number of osteoclasts in PTHrP-treated cultures. To determine whether PTHrP also potentially could have direct effects on antler osteoclasts, we studied, by confocal microscopy, the expression of the type I PTH/PTHrP receptor (PTH1R) in MNCs cultured on glass and found the receptor protein to have a nuclear localization. In situ hybridization showed that antler MNCs also expressed PTH1R and PTHrP messenger RNAs (mRNAs). PTHrP was immunolocalized in MNCs cultured on glass but was undetectable in cells resorbing a dentine substrate. In tissue sections of antler cartilage, PTHrP and PTH1R were expressed in vitronectin receptor-positive (VNR+) osteoclast-like cells localized in the perivascular stroma. Thus, these data show that PTHrP plays a role in the regulation of osteoclast differentiation in regenerating skeletal tissues and that PTHrP can have effects on osteoclastogenesis that are independent of RANKL synthesis. Ours is the first study to describe the expression of the type I PTH/PTHrP receptor in mammalian osteoclasts at a protein and mRNA level, which indicates that PTHrP also may have a direct effect on osteoclasts. This also is the first study to show a nuclear localization of the PTHIR in cells of the osteoclast lineage, although the functional significance of this observation has yet to be established.

Bone morphogenetic protein 3b expressing reindeer antler

A cDNA sequence of bone morphogenetic protein 3b (BMP-3b) of reindeer antler was produced with degenerative homology primers in polymerase chain reaction (PCR). An in situ hybridization study of BMP-3b mRNA in 1-month-old antler showed expression in most differentiated cells in the antler center. In addition, the bone-inductive capacity of the reindeer antler matrix was evaluated. Decalcified and powdered antler matrix of different stages of antler maturity was implanted in gelatin capsules under the rat dorsal muscle fascia for two implantation periods: 3 and 8 weeks. Allogenic matrix prepared from rat long bones was used as a positive control implant. Heterotopic ossification was evaluated histomorphometrically and densitometrically. Allogenic bone matrix induced rapid osteogenesis and mineral accumulation. Both endochondral and intramembranous ossification was evident, endochondral ossification being the dominant form. Mineral density in the induced ossicle was 115 +/- 48 mg/cm(3) as early as at 3 weeks and 350 +/- 69 mg/cm(3) at 8 weeks. The proportional areas of von Kossa-stained mineral were 3.67 +/- 2.1% and 11.6 +/- 0.07%, respectively. The antler preparations induced mineralization, but significantly less than the allogenic bone matrix. At 8 weeks, mineral density was significantly lower in the cast antler preparation than in the allogenic implants. The morphology of the mineralized areas of the antler preparations showed no ossification.

Diaphorase activity in sebaceous glands and related structures of the male red deer

The localisation of diaphorase was visualised by light microscopy using the dye nitro blue tetrazolium and NADPH as substrates. Under appropriate conditions, diaphorase reduces this dye to a dark blue insoluble formazan. The enzyme was located at very low activity in many tissue and glandular structures of the deer, but at very much higher activity in sebaceous glands in the dermal velvet of the antler and skin, and in additional sebaceous gland-related structures in the ear canal, prepuce and tail (scent) gland. Within sebaceous glands, activity was greatest in the outermost layers of the acini, but decreased as the cells progressed and differentiated centripetally. There was little or no difference between the staining observed when NADH was used as a substrate, compared to NADPH. There was generalised staining (usually light) for glucose-6-phosphate dehydrogenase, lactate dehydrogenase, and glycerol-3-phosphate dehydrogenase. However, this staining was not specifically localised to sebaceous glands and related structures, showing that the observed activity in these structures was due to a diaphorase that was distinct from any of the dehydrogenase activities tested. The possible role of diaphorase in sebaceous development and secretion is discussed.

Electron microscopic studies of antlerogenic cells from five developmental stages during pedicle and early antler formation in red deer (Cervus elaphus)

Previous studies using light microscopy have revealed that histogenesis of deer pedicle and antler has four ossification stages. The first of these stages is the development of the permanent pedicle. Initial development of the pedicle is from the cellular layer cells of the antlerogenic periosteum and these cells have been termed initial antlerogenic cells (IACs). Apart from the IACs, it has also been shown that the cellular layer cells of the apical periosteum/perichondrium, the peripheral periosteum of pedicles or antlers, and the marginal periosteum surrounding the pedicles are also capable of either partially or fully generating a pedicle or an antler. Therefore, these cells can all be considered antlerogenic cells and called apical antlerogenic cells (AACs), peripheral antlerogenic cells (PACs), and marginal antlerogenic cells (MACs), respectively. The aim of this study was to examine the ultrastructure of these antlerogenic cells, and to determine whether there were ultrastructural correlates with the changes of these antlerogenic cells and ossification stages. The ultrastructure of each type of antlerogenic cells was systematically examined using transmission electron microscopy, at each stage of pedicle and first antler growth. At the first ossification stage, the IACs were spindle-shaped and inactive. The most obvious feature was the presence of abundant intracellular glycogen. The MACs were similar to the IACs. During the early second stage, most of the AACs changed in appearance from preosteoblasts to prechondroblasts. Much less heterochromatin was found in the AACs than in the IACs. The most striking attribute of the AACs was the existence of intracellular collagen fibers. The MACs showed abnormal dilation of the rough endoplasmic reticulum (RER). During the late second stage, the majority of the AACs were prechondroblasts. AAC nucleoli were clearly discernible and the cisternae of the RER were arranged in parallel. The MACs contained a greater proportion of abnormally-dilated RER. During the third stage, the AACs were all prechondroblasts. The Golgi apparatus in these cells was well developed. Many free ribosomes in rosettes were scattered in the cytoplasm. Most cytoplasm of the majority of the MACs was occupied by abnormally-dilated RER (the lumen of the RER was extremely dilated and appeared electron-lucent). During the fourth stage, the AACs were similar to their counterparts from the third stage, but the boundaries of some AACs were ill-defined. Some MACs were found to be undergoing apoptosis. The PACs were becoming less and less active from distal to proximal along the shaft of the antler. It is a novel finding that antlerogenic cells change in appearance and subcellular content from preosteoblasts to prechondroblasts prior to the transition from intramembranous to endochondral ossification during pedicle formation. Therefore, the differentiation process from antlerogenic cells to chondroblasts is a matter of maturation from prechondroblasts to chondroblasts. The fact that the antlerogenic cells are rich in glycogen makes them more like embryonic cells. The local membrane deficiency of some AACs at the fourth stage and the presence of mature collagen fibrils within the AACs may reflect the unusually high demand for collagen fibrils during the period of rapid antler growth.

Isolation, characterization and localization of glycosaminoglycans in growing antlers of wapiti (Cervus elaphus)

Glycosaminoglycans were isolated from the four sections (tip, upper, middle and base) of the main beam of growing antlers of wapiti (Cervus elaphus) by papain digestion and DEAE-Sephacel chromatography. Chondroitin sulfate was the major glycosaminoglycan in each section of antler accounting for, on average, 88% of the total uronic acid. The yield of chondroitin sulfate liberated from the tissue was approximately 6-fold greater in the cartilaginous (tip and upper) sections than in the bony (middle and base) sections. This was consistent with the higher intensity of glycosaminoglycan staining with either Alcian Blue or Safranin-O. The majority (average 88%) of chondroitin sulfate was precipitated with 40 and 50% ethanol. The average molecular size of chondroitin sulfate determined by gel chromatography on Sephacryl S-300 tended to be greater in the 40% ethanol than in the 50% ethanol fraction. In either fraction, the molecular size of chondroitin sulfate was smaller in cartilaginous tissues than in osseous tissues of growing antler. In addition to chondroitin sulfate, the antler contained small amounts of hyaluronic acid, dermatan sulfate and keratan sulfate. The immunohistochemical study showed wide distribution of chondroitin sulfate, decorin, and keratan sulfate throughout the antler. On the other hand, keratan sulfate was more prominent in the cartilaginous sections than in the bony sections where the anti-keratan sulfate monoclonal antibody staining was seen in the osteoid tissue only.

Expression of neurotrophin-3 in the growing velvet antler of the red deer Cervus elaphus

Antlers are organs of bone which regenerate each year from the heads of male deer. In addition to bone, support tissues such as nerves also regenerate. Nerves must grow at up to 1 cm/day. The control of this rapid growth of nerves is unknown. We examined the relative expression of neurotrophin-3 (NT-3) mRNA in the different tissues of the growing antler tip and along the epidermal/dermal layer of the antler shaft of the red deer Cervus elaphus, using semi-quantitative reverse transcription-polymerase chain reaction. Expression in the tip was found to be highest in the epidermal/dermal layer and lowest in the cartilaginous layer in all developmental stages examined. These data correlate well with the density and pattern of innervation of these tissues. Along the epidermal/dermal layer of the antler shaft, expression was highest in the segments subjacent to the tip and lowest near the base, arguing for differences in the temporal expression of NT-3 in these segments. The expression of NT-3 in cells isolated from the different layers of 60-day antlers did not mirror that observed when whole tissues were used and may suggest regional specificity of NT-3 expression within antler tissues.

Deer antler does not represent a typical endochondral growth system: immunoidentification of collagen type X but little collagen type II in growing antler tissue

The collagen isotypes present at early (6 week) and late (5 month) stages of growing deer antler were isolated and identified. Pepsin-digested collagens were separated by differential salt fractionation, SDS-PAGE and Western blotting and subsequently identified by immunostaining. Cyanogen bromide digestion of antler tissue was used to establish a collagen type-specific pattern of peptides, and these were also identified by immunoblotting. Collagen type I was found to be the major collagen in both early- and late-stage antler. Collagen type II was present in the young antler in small amounts but was not confined to the soft "cartilaginous" tip of the antler. Collagen type XI was found in the pepsin digest of the young antler, but collagen type IX was not present at either stage of antler growth. Collagen type X was found in the young antler in all fractions studied. Microscopic study showed that the deer antler did not possess a discrete growth plate as found in endochondral bone growth. Unequivocal immunolocalization of the different collagen types in the antler were unsuccessful. These results show that, despite the presence in the antler of many cartilage collagens, growth does not occur through a simple endochondral process.

Sodium economy in white-tailed deer (Odocoileus virginianus)

Sodium is considered the mineral most limiting to growth and reproduction of mammalian herbivores worldwide. Notwithstanding the large database on physiological adaptations to low sodium intake, information on maintenance sodium requirements and sodium dynamics of mammals is depauperate. We measured sodium intake and output in adult, nonreproductive white-tailed deer (n = 15) over four seasons to estimate daily requirements for sodium on a seasonal and an annual basis. Dietary sodium content was based on best available predictions of sodium requirements. With regression techniques, we estimated metabolic fecal excretion and endogenous urinary losses of sodium. Average daily sodium requirement, defined as the minimum sodium intake at which intake equaled excretion, was estimated to be 3.27 mg kg-1 body mass d-1. Seasonal estimates did not vary. We propose that sodium requirements for maintenance in mammalian herbivores scale to body mass at an exponent that is similar to that for metabolic rate and forage intake (0.71-0.75). Development of an allometric relationship between sodium need and body mass would permit stronger inference regarding the role of sodium in population regulation, foraging decisions, or distribution and movements of mammalian herbivores.

Fluoride content and mineralization of red deer (Cervus elaphus) antlers and pedicles from fluoride polluted and uncontaminated regions

Fluoride, calcium, and phosphorus content as well as ashpercentage and ash density of primary antlers and pedicle bones were studiedin nine yearling red deer stags from a fluoride polluted region in NorthBohemia (Czech Republic) and in nine control animals from two uncontaminatedareas in West Germany. Fluoride levels in antlers (845 +/- 257 mgF-/kg ash, mean +/- SD) and pedicles (1,448 +/- 461 mgF-/kg ash) of the N-Bohemian specimens exceeded that of thecontrols (antlers: 206 +/- 124 mg F-/kg ash, pedicles:322 +/- 157 mg F-/kg ash) by factors of 4.1 and 4.5,respectively. Antler and pedicle fluoride concentrations of the deer(n = 18) were closely correlated (r = 0.975,p < 0.001). Analyses of ash percentage and ash density revealed that theantlers of the N-Bohemian deer contained significantly less mineral and weresignificantly less dense than both their pedicles and the control antlers. Inthe pooled antler samples (n = 18), bone fluoride concentration wasnegatively correlated with ash density (r = -0.826, p < 0.001)and ash percentage (r = -0.759, p < 0.001), whereas nonsignificant, positive correlations existed for the pooled pedicle samples. Ash percentage and ash density of the antlers and their correspondingpedicles were uncorrelated. It is concluded that increased fluoride exposureof deer leads to reduced mineral content and mineral density of antler boneand that it is the rapidity of their growth and mineralization that makesantlers especially susceptible to fluoride action. Due to their ability toaccumulate high amounts of fluoride during a defined, limited timespan andthe apparently dose-dependent negative effect of fluoride on their densityand mineral content, (primary) antlers can be recommended as monitoring toolsfor studying environmental pollution by fluorides.

Bone morphogenetic protein 2 transcripts in rapidly developing deer antler tissue contain an extended 5' non-coding region arising from a distal promoter

To understand the regulation of the BMP-2 gene expression, we recently isolated the BMP-2 gene from a mouse genomic library and characterized the exon-intron structure and promoter. RNase protection assay using poly (A)+ RNA of mouse osteoblasts demonstrates that two regions in BMP-2 gene are protected by antisense mouse BMP-2 RNA probes. These results demonstrate that BMP-2 gene utilizes two alternative promoters, a distal and a proximal promoter. In the present study we demonstrate that BMP-2 mRNA from rapidly growing deer antler tissue has an extended 5' non-coding region compared with the human and rat BMP-2 mRNA. The extended 5' non-coding region in the deer mRNA represents transcripts from the upstream distal promoter. This is the first evidence of a natural BMP-2 mRNA from a bone-forming tissue that most likely initiated from the distal transcription start site.