Enhanced potency of an IgM-like nanobody targeting conserved epitope in SARS-CoV-2 spike N-terminal domain.

Almost all the neutralizing antibodies targeting the receptor-binding domain (RBD) of spike (S) protein show weakened or lost efficacy against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged or emerging variants, such as Omicron and its sub-variants. This suggests that highly conserved epitopes are crucial for the development of neutralizing antibodies. Here, we present one nanobody, N235, displaying broad neutralization against the SARS-CoV-2 prototype and multiple variants, including the newly emerged Omicron and its sub-variants. Cryo-electron microscopy demonstrates N235 binds a novel, conserved, cryptic epitope in the N-terminal domain (NTD) of the S protein, which interferes with the RBD in the neighboring S protein. The neutralization mechanism interpreted via flow cytometry and Western blot shows that N235 appears to induce the S1 subunit shedding from the trimeric S complex. Furthermore, a nano-IgM construct (MN235), engineered by fusing N235 with the human IgM Fc region, displays prevention via inducing S1 shedding and cross-linking virus particles. Compared to N235, MN235 exhibits varied enhancement in neutralization against pseudotyped and authentic viruses in vitro. The intranasal administration of MN235 in low doses can effectively prevent the infection of Omicron sub-variant BA.1 and XBB in vivo, suggesting that it can be developed as a promising prophylactic antibody to cope with the ongoing and future infection.

Efficacy of natural products on premature ovarian failure: a systematic review and meta-analysis of preclinical studies.

OBJECTIVE: This study aims to investigate the effects of natural products on animal models of premature ovarian failure (POF). METHODS: We conducted comprehensive literature searches and identified relevant studies that examined the protective effects of natural products on experimental POF. We extracted quantitative data on various aspects such as follicular development, ovarian function, physical indicators, oxidative stress markers, inflammatory factors, and protein changes. The data was analyzed using random-effects meta-analyses, calculating pooled standardized mean differences and 95% confidence intervals. Heterogeneity was assessed using the I2 statistic, and bias was estimated using the SYRCLE tool. RESULTS: Among the 879 reviewed records, 25 articles met our inclusion criteria. These findings demonstrate that treatment with different phytochemicals and marine natural products (flavonoids, phenols, peptides, and alkaloids, etc.) significantly improved various aspects of ovarian function compared to control groups. The treatment led to an increase in follicle count at different stages, elevated levels of key hormones, and a decrease in atretic follicles and hormone levels associated with POF. This therapy also reduced oxidative stress (specifically polyphenols, resveratrol) and apoptotic cell death (particularly flavonoids, chrysin) in ovarian granulosa cells, although it showed no significant impact on inflammatory responses. The certainty of evidence supporting these findings ranged from low to moderate. CONCLUSIONS: Phytochemicals and marine natural product therapy (explicitly flavonoids, phenols, peptides, and alkaloids) has shown potential in enhancing folliculogenesis and improving ovarian function in animal models of POF. These findings provide promising strategies to protect ovarian reserve and reproductive health. Targeting oxidative stress and apoptosis pathways may be the underlying mechanism.

Application of mesenchymal stem cell therapy for premature ovarian insufficiency: Recent advances from mechanisms to therapeutics.

The incidence of premature ovarian insufficiency (POI) is increasing worldwide, particularly among younger women, posing a significant challenge to fertility. In addition to menopausal symptoms, POI leads to several complications that profoundly affect female reproductive function and overall health. Unfortunately, current clinical treatment strategies for this condition are limited and often yield unsatisfactory outcomes. These approaches typically involve hormone replacement therapy combined with psychological support. Recently, mesenchymal stem cell (MSC) therapies for POI have garnered considerable attention in global research. MSCs can restore ovarian reproductive and endocrine functions through diverse mechanisms, including controlling differentiation, promoting angiogenesis, regulating ovarian fibrosis, inhibiting apoptosis, enhancing autocrine and paracrine effects, suppressing inflammation, modulating the immune system, and genetic regulation. This editorial offers a succinct summary of the application of MSC therapy in the context of POI, providing evidence for groundbreaking medical approaches that have potential to enhance reproductive health and overall well-being for women.

Mechanisms of Bushen Tiaoxue Granules against controlled ovarian hyperstimulation-induced abnormal morphology of endometrium based on network pharmacology.

Bushen Tiaoxue Granules (BTG) is an empirical Chinese herbal formula that has been used for the treatment of subfertility. The protective effect of BTG on controlled ovarian hyperstimulation (COH)-induced impaired endometrial receptivity has been reported in our previous study. This study aims to explore the mechanisms of BTG on ameliorating abnormal morphology of endometrium based on network pharmacology. Active compounds of BTG were identified via the traditional Chinese medicine systems pharmacology and UPLC-MS technology. The SwissTargetPrediction platform and HERB database were used to screen out the putative targets of BTG. Potential targets of endometrial dysfunction caused by COH were obtained from three GEO databases. Through the STRING database, the protein-protein interaction was carried out according to the cross-common targets of diseases and drugs. GO terms and KEGG pathways enrichment analyses were conducted via the Metascape database. AutoDock Vina was used for docking validation of the affinity between active compounds and potential targets. Finally, in vivo experiments were used to verify the potential mechanisms derived from network pharmacology study. A total of 141 effective ingredients were obtained from TCMSP and nine of which were verified in UPLC-MS. Six genes were selected through the intersection of 534 disease related genes and 165 drug potential targets. Enrichment analyses showed that BTG might reverse endometrial dysfunction by regulating adherens junction and arachidonic acid metabolism. Hematoxylin-eosin staining revealed that BTG ameliorated the loose and edematous status of endometrial epithelium caused by COH. The protein expression of FOXO1A, ß-Catenin and COX-2 was decreased in the COH group, and was up-regulated by BTG. BTG significantly alleviates the edema of endometrial epithelium caused by COH. The mechanisms may be related to adheren junctions and activation of arachidonic acid metabolism. The potential active compounds quercetin, taxifolin, kaempferol, eriodictyol, and isorhamnetin identified from the BTG exhibit marginal cytotoxicity. Both high and low concentrations of kaempferol, eriodictyol, and taxifolin are capable of effectively ameliorating impaired hESC cellular activity.

Gene expression profiles of skin from cyclin dependent kinases 5-knockdown mice.

OBJECTIVE: This study aimed to identify genes regulated by cyclin dependent kinases 5 (CDK5) that participate in hair pigmentation in mice. METHODS: The mRNA expression profiles of skin samples from CDK5-knockdown mice were constructed using high-throughput RNA sequencing and compared with those of wild-type mice. RESULTS: In total, 8,002 known genes were differentially expressed between CDK5-knockdown and wild-type mice. Of these, 3,658 were upregulated and 4,344 were downregulated in the skin of CDK5-knockdown mice. An additional 318 previously unknown genes were also differentially expressed, with 171 downregulated and 147 upregulated genes in the skin of CDK5-knockdown mice. Of the known genes expressed in mouse skin, 80 were associated with hair color, with 61 showing lower expression and 19 exhibiting higher expression in skin of CDK5-knockdown mice. Importantly, the expression of the tyrosinase-related protein 1 (TYRP1) and the calcium signaling pathway were also found to be regulated by CDK5, suggesting that pigmentation is regulated by CDK5 via the calcium signaling pathway and TYRP1. CONCLUSION: The transcriptome profiles obtained from the skin of CDK5-knockdown mice compared to wild-type mice provide a valuable resource to help understand the mechanism by which CDK5 regulates melanogenesis in mice and other animals.

Burden and attributable risk factors of ischemic stroke in China from 1990 to 2019: an analysis from the Global Burden of Disease Study 2019.

Background: The epidemiologic characteristics and attributable risk factors of ischemic stroke in China have changed over the past three decades. An up-to-date analysis on deaths, disability-adjusted life-years (DALYs), prevalence, incidence, and attributable risk factors of ischemic stroke for China is needed. This study aims to provide a comprehensive analysis of burden and attributable risk factors of ischemic stroke at national level in China by sex from 1990 to 2019. Methods: This is a secondary analysis of the Global Burden of Disease (GBD) study 2019. All data used in this study was derived from the 2019 GBD study. Deaths, DALYs, prevalence, incidence, and attributable risk factors of ischemic stroke in China by sex from 1990 to 2019 were analyzed. Results: From 1990 to 2019, the age-standardized deaths rate decreased by 3.3%, age-standardized DALYs rate decreased by 4%, age-standardized prevalence rate increased by 33.5%, and age-standardized incidence rate of ischemic stroke in China increased by 34.7%. In 2019, ambient particulate matter pollution became an important risk factor, whereas household air pollution from solid fuels was no longer a major risk factor for ischemic stroke in China. Burden of ischemic stroke was higher in China compared to other regions. Ambient particulate matter pollution among men, and diet high in sodium, smoking, household air pollution from solid fuels among women account for the increased deaths/DALYs due to ischemic stroke in China. Conclusion: Our study revealed that great changes have occurred in burden and attributable risk factors of ischemic stroke in China in the past three decades. Distinct sex-specific differences are observed in burden and attributable risk factors.

A modified mouse model of haemorrhagic transformation associated with tPA administration after thromboembolic stroke.

Objective: To establish a new mouse model of haemorrhagic transformation associated with delayed tissue-type plasminogen activator (tPA) treatment to provide a novel tool to study therapeutic strategies for haemorrhagic transformation. Methods: Male C57BL/6 mice were subjected to carotid artery thrombosis stimulated with ferric chloride. The thrombus was then mechanically detached to induce migration toward the intracranial circulation. To induce haemorrhagic transformation, mice were intravenously injected with 10 mg/kg tPA 4.5 h after the onset of ischaemia and were sacrificed 24 h after tPA treatment. Results: In this new model, administration of tPA 4.5 h after stroke exacerbated the risk of intracerebral haemorrhage. Thrombolysis with tPA also exacerbated cerebral infarction, brain oedema, blood-brain barrier breakdown, and neurological deficits. However, cerebral blood flow was not significantly affected. Conclusion: The present model is reproducible, easy to perform, and mimics the clinical situation of haemorrhagic transformation after tPA treatment in humans. This modified model can be used as a new tool to test experimental drugs for haemorrhagic transformation associated with delayed tPA administration after an ischaemic stroke.

Two pan-SARS-CoV-2 nanobodies and their multivalent derivatives effectively prevent Omicron infections in mice.

With the widespread vaccinations against coronavirus disease 2019 (COVID-19), we are witnessing gradually waning neutralizing antibodies and increasing cases of breakthrough infections, necessitating the development of drugs aside from vaccines, particularly ones that can be administered outside of hospitals. Here, we present two cross-reactive nanobodies (R14 and S43) and their multivalent derivatives, including decameric ones (fused to the immunoglobulin M [IgM] Fc) that maintain potent neutralizing activity against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after aerosolization and display not only pan-SARS-CoV-2 but also varied pan-sarbecovirus activities. Through respiratory administration to mice, monovalent and decameric R14 significantly reduce the lung viral RNAs at low dose and display potent pre- and post-exposure protection. Furthermore, structural studies reveal the neutralizing mechanisms of R14 and S43 and the multiple inhibition effects that the multivalent derivatives exert. Our work demonstrates promising convenient drug candidates via respiratory administration against SARS-CoV-2 infection, which can contribute to containing the COVID-19 pandemic.

Genome-Wide DNA Methylation Profile Indicates Potential Epigenetic Regulation of Aging in the Rhesus Macaque Thymus.

We analyzed whole-genome bisulfite sequencing (WGBS) and RNA sequencing data of two young (1 year old) and two adult (9 years old) rhesus macaques (Macaca mulatta) to characterize the genomic DNA methylation profile of the thymus and explore the molecular mechanism of age-related changes in the thymus. Combining the two-omics data, we identified correlations between DNA methylation and gene expression and found that DNA methylation played an essential role in the functional changes of the aging thymus, especially in immunity and coagulation. The hypomethylation levels of C3 and C5AR2 and the hypermethylation level of C7 may lead to the high expressions of these genes in adult rhesus macaque thymuses, thus activating the classical complement pathway and the alternative pathway and enhancing their innate immune function. Adult thymuses had an enhanced coagulation pathway, which may have resulted from the hypomethylation and upregulated expressions of seven coagulation-promoting factor genes (F13A1, CLEC4D, CLEC4E, FCN3, PDGFRA, FGF2 and FGF7) and the hypomethylation and low expression of CPB2 to inhibit the degradation of blood clots. Furthermore, the functional decline in differentiation, activation and maturation of T cells in adult thymuses was also closely related to the changes in methylation levels and gene expression levels of T cell development genes (CD3G, GAD2, ADAMDEC1 and LCK) and the thymogenic hormone gene TMPO. A comparison of the age-related methylated genes among four mammal species revealed that most of the epigenetic clocks were species-specific. Furthermore, based on the genomic landscape of allele-specific DNA methylation, we identified several age-related clustered sequence-dependent allele-specific DNA methylated (cS-ASM) genes. Overall, these DNA methylation patterns may also help to assist with understanding the mechanisms of the aging thymus with the epigenome.

Deoxynivalenol damages the intestinal barrier and biota of the broiler chickens.

BACKGROUND: In the livestock feed industry, feed and feed raw materials are extremely susceptible to mycotoxin contamination. Deoxynivalenol (DON) is one of the main risk factors for mycotoxin contamination in broiler feed and feedstuff, however, there is still little knowledge about this. Hence, the purpose of this study was to explore the toxicity effect of DON on the intestinal barrier and the microecological balance of the biota in broiler chickens. RESULTS: In our present study, we compared the pathological scores of the small intestines of broilers on the 5th, 7th, and 10th day, and chose the 7th day to analyze the small intestine histomorphology, tight junctions, and cecal biota of the broilers. The results showed the damage to the small intestine worsened over time, the small intestinal villi of broilers were breakage, the tight junctions of the small intestine were destroyed, the cecal biota was unbalanced, and the growth performance of broilers was reduced on the 7th day. CONCLUSIONS: DON could damage the functional and structural completeness of the intestinal tract, disorder the Intestinal biota, and finally lead to declined broiler performance. Our study provided a basis for the prevention and treatment of DON in broiler production.

Functional network characteristics based on EEG of patients in acute ischemic stroke: A pilot study.

BACKGROUND: Ischemic stroke is a common type of stroke associated with reorganization of functional network of the brain. OBJECTIVE: This pilot study aimed to investigate the characteristics of functional brain networks based on EEG in patients with acute ischemic stroke. METHODS: Seven patients with ischemic stroke within 72 hours of onset and seven healthy controls were enrolled in the study. Dynamic EEG monitoring and clinical information were repeatedly collected within 72 hours (T1), on the 5th day (T2), and on the 7th day (T3) of stroke onset. A directed transfer function was employed to construct functional brain connection patterns. Graph theoretical analysis was performed to evaluate the characteristics of functional brain networks. RESULTS: First, we found that the brain networks of ischemic stroke patients were quite different from the healthy controls. The clustering coefficient (0.001 < Threshold < 0.2) in Delta, Theta, and Alpha bands for the patients were significantly lower (P < 0.01) and the shortest path length in all bands (0.001 < Threshold < 0.2) for the patients were significantly longer (P < 0.01). Moreover, the peaks of the shortest path length for the patients seemed to be higher in all bands with larger thresholds. Secondly, the brain networks for the patients showed a characterized time-variation pattern. The clustering coefficient (0.001 < Threshold < 0.2) of T1 was higher than that of T2 in alpha band (P < 0.01). The shortest path length (0.001 < Threshold < 0.2) of T3 was shorter than that of T2 (P < 0.01) in all bands, and the peak of T3 was numerically higher than that of T2 in all bands with narrower thresholds. CONCLUSION: Functional brain networks in patients with acute ischemic stroke showed impaired global functional integration and decreased efficiency of information transmission compared with healthy subjects. The shortening of the shortest path length during the recovery indicates neural plasticity and reorganization.

Qa-1b functions as an oncogenic factor in mouse melanoma cells.

BACKGROUND: Malignant melanoma is one kind of rare cancer in human and animals, which occurs not only in skin but also in the mucous membranes of the nose, mouth, anus, digestive tract, and in the uvea (choroid) of the eye. In order to develop therapies, a better understanding of the genetic landscape and signal pathways are needed. Numerous studies highlighted the importance of NKG2A-HLA-E in tumor immunotherapy, but the function and mechanism of HLA-E in tumor cells have seldom been studied alone. The statistical analyses from publicly available database Oncomine and The Cancer Genome Atlas (TCGA) showed that HLA-E is highly expressed in melanoma compared to non-transformed counterparts. In addition, melanoma patients with HLA-E high expression had a worse OS rate than the patients with low expression. These data indicate the importance of HLA-E in human melanoma. Qa-1b is the homolog of HLA-E in mouse. OBJECTIVE: To investigate the function and mechanism of Qa-1b in mouse melanoma. METHODS: Mouse melanoma cell line B16-F10 and allogenic melanoma model were used to investigate the function and mechanism of Qa-1b in melanoma. RESULTS: Qa-1b was highly expressed in B16-F10 compared with normal mouse epidermal cells. Qa-1b knockdown inhibited B16-F10 cell proliferation and migration in vitro and allogenic melanoma process in vivo. Furthermore, Qa-1b knockdown promoted cell cycle arrest at G0/G1 phase and cell apoptosis through Ras-Raf-MAPK signal pathway. CONCLUSION: Qa-1b functions as an oncogenic factor and it can be used as a new therapeutic target in melanoma.

Generation and Characterization of a Nanobody Against SARS-CoV.

The sudden emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) has caused global panic in 2003, and the risk of SARS-CoV outbreak still exists. However, no specific antiviral drug or vaccine is available; thus, the development of therapeutic antibodies against SARS-CoV is needed. In this study, a nanobody phage-displayed library was constructed from peripheral blood mononuclear cells of alpacas immunized with the recombinant receptor-binding domain (RBD) of SARS-CoV. Four positive clones were selected after four rounds of bio-panning and subjected to recombinant expression in E. coli. Further biological identification demonstrated that one of the nanobodies, S14, showed high affinity to SARS-CoV RBD and potent neutralization activity at the picomole level against SARS-CoV pseudovirus. A competitive inhibition assay showed that S14 blocked the binding of SARS-CoV RBD to either soluble or cell-expressed angiotensin-converting enzyme 2 (ACE2). In summary, we developed a novel nanobody targeting SARS-CoV RBD, which might be useful for the development of therapeutics against SARS.

Uncinate fasciculus and its cortical terminals in aphasia after subcortical stroke: A multi-modal MRI study.

Aphasia, one of the most common cognitive impairments after stroke, is commonly considered to be a cortical deficit. However, many studies have reported cases of post subcortical stroke aphasia (PSSA). The pathology and recovery mechanism of PSSA remain unclear. This study aimed to investigate PSSA mechanism through a multimodal magnetic resonance imaging (MRI) approach and a two-session study design (baseline and one month after treatment). Thirty-six PSSA patients and twenty-four matched healthy controls (HC) were included. All patients had subcortical infarctions involving left subcortical white matter for 1 to 6 months. The patients underwent MRI scan and Western Aphasia Battery (WAB) examination before and after one month's comprehensive treatment. Region-wise lesion-symptom mapping (RLSM), tractography, fractional anisotropy (FA), and amplitude of low-frequency fluctuations (ALFF) analysis were conducted. After MRI preprocessing and exclusion, FA analysis included 35 patients pre-treatment and 16 patients post-treatment. ALFF analysis included 30 patients pre-treatment and 14 patients post-treatment. We found: 1) the amount of damage in the left uncinate fasciculus (UF) was associated with WAB aphasia quotient (AQ); 2) the left UF FA and left temporal pole (TP) ALFF were decreased and positively correlated with WAB-AQ, spontaneous speech, and naming in PSSA patients; and 3) PSSA patients showed increased left TP ALFF when their language ability recovered after treatment. The left TP ALFF change was positively correlated with AQ change. Our results demonstrate the importance of left UF and left TP (one of the cortical terminals of the left UF) in PSSA pathology and recovery. These results may further provide support for the disconnection theory in the mechanism of PSSA.

Evaluating the Long-Term Efficacy of Acupuncture Therapy for Subacute Poststroke Aphasia: Study Protocol for a Randomized, Blinded, Controlled, Multicentre Trial.

BACKGROUND: Poststroke aphasia (PSA) is a disabling condition that decreases the quality of life, and the duration of the disease harms the quality of life of PSA patients. Acupuncture has been widely employed for PSA. There is some evidence for the immediate treatment efficacy of acupuncture for PSA; however, long-term results after acupuncture may be poorer. METHODS: This is a multicentre, randomized, blinded, nonacupoint (NA) acupuncture controlled, multimodal neuroimaging clinical trial. A total of 48 subjects with subacute PSA will be randomly assigned to an acupoint group or an NA control group. The acupoint group will receive acupuncture with normal needling at DU20, EX-HN1, HT5, GB39, EX-HN12, EX-HN13, and CV23. The NA control group will receive acupuncture in locations not corresponding to acupuncture points as sham acupoints. Both groups will receive identical speech and language therapy thrice a week for four weeks. The primary outcome will be the change in the aphasia quotient (AQ) score measured by the Western Aphasia Battery (WAB) test during the 12th week after randomization. Participants will be blindly assessed at prerandomization (baseline) and 4 weeks, 12 weeks, and 24 weeks after randomization. The secondary outcomes include the Boston Diagnostic Aphasia Examination (BDAE) score, the Disease Prognosis Scale score for ischaemic stroke, etc. Magnetic resonance imaging (MRI) and electroencephalogram (EEG) will also be performed at 4-time intervals as secondary outcomes. All scores and image evaluations will be taken at the same point as the linguistic evaluation. The multilevel evaluation technique will be used to assess the long-term efficacy of acupuncture therapy. MRI scans and EEG will be used to assess acupuncture-related neuroplasticity changes. Discussion. The results from our trial will help to supply evidence for the long-term acupuncture effects for PSA over a long follow-up period. It will provide valuable information for future studies in the field of PSA treatment. The trial was registered at the Chinese Clinical Trial Registry on 16 March 2020 (ChiCTR2000030879).

Lesion Distribution and Early Changes of Right Hemisphere in Chinese Patients With Post-stroke Aphasia.

The role of the right hemisphere (RH) in post-stroke aphasia (PSA) has not been completely understood. In general, the language alterations in PSA are normally evaluated from the perspective of the language processing models developed from Western languages such as English. However, the successful application of the models for assessing Chinese-language functions in patients with PSA has not been reported. In this study, the features of specific language-related lesion distribution and early variations of structure in RH in Chinese patients with PSA were investigated. Forty-two aphasic patients (female: 13, male: 29, mean age: 58 ± 12 years) with left hemisphere (LH) injury between 1 and 6 months after stroke were included. The morphological characteristics, both at the levels of gray matter (GM) and white matter (WM), were quantified by 3T multiparametric brain MRI. The Fridriksson et al.'s dual-stream model was used to compare language-related lesion regions. Voxel-based lesion-symptom mapping (VLSM) analysis has been performed. Our results showed that lesions in the precentral, superior frontal, middle frontal, and postcentral gyri were responsible for both the production and comprehension dysfunction of Chinese patients with PSA and were quite different from the lesions described by using the dual-stream model of Fridriksson et al. Furthermore, gray matter volume (GMV) was found significantly decreased in RH, and WM integrity was disturbed in RH after LH injury in Chinese patients with PSA. The different lesion patterns between Chinese patients with PSA and English-speaking patients with PSA may indicate that the dual-stream model of Fridriksson et al. is not suitable for the assessment of Chinese-language functions in Chinese patients with PSA in subacute phase of recovery. Moreover, decreased structural integrity in RH was found in Chinese patients with PSA.

Genomic analysis of the domestication and post-Spanish conquest evolution of the llama and alpaca.

BACKGROUND: Despite their regional economic importance and being increasingly reared globally, the origins and evolution of the llama and alpaca remain poorly understood. Here we report reference genomes for the llama, and for the guanaco and vicuña (their putative wild progenitors), compare these with the published alpaca genome, and resequence seven individuals of all four species to better understand domestication and introgression between the llama and alpaca. RESULTS: Phylogenomic analysis confirms that the llama was domesticated from the guanaco and the alpaca from the vicuña. Introgression was much higher in the alpaca genome (36%) than the llama (5%) and could be dated close to the time of the Spanish conquest, approximately 500 years ago. Introgression patterns are at their most variable on the X-chromosome of the alpaca, featuring 53 genes known to have deleterious X-linked phenotypes in humans. Strong genome-wide introgression signatures include olfactory receptor complexes into both species, hypertension resistance into alpaca, and fleece/fiber traits into llama. Genomic signatures of domestication in the llama include male reproductive traits, while in alpaca feature fleece characteristics, olfaction-related and hypoxia adaptation traits. Expression analysis of the introgressed region that is syntenic to human HSA4q21, a gene cluster previously associated with hypertension in humans under hypoxic conditions, shows a previously undocumented role for PRDM8 downregulation as a potential transcriptional regulation mechanism, analogous to that previously reported at high altitude for hypoxia-inducible factor 1α. CONCLUSIONS: The unprecedented introgression signatures within both domestic camelid genomes may reflect post-conquest changes in agriculture and the breakdown of traditional management practices.

MicroRNA-379 mediates pigmentation, migration and proliferation of melanocytes by targeting the insulin-like growth factor 1 receptor.

Melanogenesis, migration and proliferation of melanocytes are important factors that determine the hair colours of mammals. MicroRNAs (miRNAs) have been shown to be closely related to these processes. In melanocytes of alpacas, insulin-like growth factor 1 (IGF1) has been shown to improve melanogenesis through the cyclic AMP (cAMP) pathway. miR-379 was predicted to target insulin-like growth factor (IGF) receptor 1 (IGF1R), which binds to IGF1. Therefore, we hypothesized that miR-379 could mediate melanogenesis, migration and proliferation of melanocytes. Here, we report that miR-379 was highly expressed in alpaca melanocytes. Subsequent overexpression of miR-379 in alpaca melanocytes led to the generation of the phenotype of melanogenesis, proliferation and migration. In addition, the expression of genes related to these phenotypes in melanocytes was detected. Our results showed that miR-379 targets IGF1R in melanocytes. The overexpression of miR-379 stimulated dendrite extension or elongation and limited the perinuclear distribution of melanin, but inhibited melanogenesis via cAMP response element (CRE)-binding protein (CREB)/microphthalmia-associated transcription factor (MITF) pathway. miR-379 attenuated melanocyte migration by downregulating the focal adhesion kinase (FAK) and enhanced melanocyte proliferation by upregulating protein kinase B (AKT). These observations suggest the involvement of miR-379 in the physiological regulation of melanocytes, mediated by targeting IGF1R on insulin receptor (IR) compensation and subsequent crosstalk.

miRNA-183∼96∼182 regulates melanogenesis, cell proliferation and migration in B16 cells.

Melanoma is a highly invasive malignant skin tumor having high metastatic rate and poor prognosis. The biology of melanoma is controled by miRNAs. The miRNA-183 cluster, which is composed of miRNA-183∼96∼182 genes, plays an important roles in tumor development. In order to investigate the role and action of miRNA-183 cluster in B16 cells, we overexpressed and knocked down miRNA-183 cluster in B16 cells. Using bioinformatics analysis, we predicted that the key framscript factor of melangenic genes. Microphthalmia-associated transcription factor (MITF) is one of the targets of miRNA-183 cluster. The results of Luciferase activity assays confirmed that MITF was targeted by miRNA-183 cluster. Overexpression and knockdown of miRNA-183 cluster in B16 cells resulted in down and up regulation of MITF expression, respectively at both mRNA and protein levels. Furthmore, overexpression and knockdown of the miRNA-183 cluster in B16 cells decreased and increased the expression of mRNA and protein of melangenic genes tyrosinase (TYR), and tyrosinase-related protein 1 (TYRP1), dopachrome-tautomerase (DCT), as well as the production of melanins and eumelanin production, respectively. On the proliferation and migration pathway, overexpression and knockdown of miRNA-183 cluster increased and decreased, respectively the expression of mRNA and protein of mitogen-activated protein kinase 1 (MEK1), extracellular regulated protein kinases1/2 (ERK1/2) and cAMP-responsive-element binding protein (CREB). These results indicated that miRNA-183 cluster regulated melanogenesis in B16 cells as well as cell proliferation and migration by directly targeting MITF through migration pathway.