Human adenovirus (HAdV) infection in children with acute respiratory tract infections in Guangzhou, China, 2010-2021: a molecular epidemiology study.

BACKGROUND: Human adenovirus (HAdV) infection can cause a variety of diseases. It is a major pathogen of pediatric acute respiratory tract infections (ARIs) and can be life-threatening in younger children. We described the epidemiology and subtypes shifting of HAdV among children with ARI in Guangzhou, China. METHODS: We conducted a retrospective study of 161,079 children diagnosed with acute respiratory illness at the Guangzhou Women and Children's Medical Center between 2010 and 2021. HAdV specimens were detected by real-time PCR and the hexon gene was used for phylogenetic analysis. RESULTS: Before the COVID-19 outbreak in Guangzhou, the annual frequency of adenovirus infection detected during this period ranged from 3.92% to 13.58%, with an epidemic peak every four to five years. HAdV demonstrated a clear seasonal distribution, with the lowest positivity in March and peaking during summer (July or August) every year. A significant increase in HAdV cases was recorded for 2018 and 2019, which coincided with a shift in the dominant HAdV subtype from HAdV-3 to HAdV-7. The latter was associated with a more severe disease compared to HAdV-3. The average mortality proportion for children infected with HAdV from 2016 to 2019 was 0.38% but increased to 20% in severe cases. After COVID-19 emerged, HAdV cases dropped to 2.68%, suggesting that non-pharmaceutical interventions probably reduced the transmission of HAdV in the community. CONCLUSION: Our study provides the foundation for the understanding of the epidemiology of HAdV and its associated risks in children in Southern China.

The crosstalk between endothelial cells and vascular smooth muscle cells aggravates high phosphorus-induced arterial calcification.

Arterial calcification is highly prevalent, particularly in patients with end-stage renal disease (ESRD). The osteogenic differentiation of vascular smooth muscle cells (VSMCs) is the critical process for the development of arterial calcification. However, the detailed mechanism of VSMCs calcification remains to be elucidated. Here, we investigated the role of exosomes (Exos) derived from endothelial cells (ECs) in arterial calcification and its potential mechanisms in ESRD. Accelerated VSMCs calcification was observed when VSMCs were exposed to ECs culture media stimulated by uremic serum or high concentration of inorganic phosphate (3.5 mM Pi). and the pro-calcification effect of the ECs culture media was attenuated by exosome depletion. Exosomes derived from high concentrations of inorganic phosphate-induced ECs (ECsHPi-Exos) could be uptaken by VSMCs and promoted VSMCs calcification. Microarray analysis showed that miR-670-3p was dramatically increased in ECsHPi-Exos compared with exosomes derived from normal concentrations of inorganic phosphate (0.9 mM Pi) induced ECs (ECsNPi-Exos). Mechanistically, insulin-like growth factor 1 (IGF-1) was identified as the downstream target of miR-670-3p in regulating VSMCs calcification. Notably, ECs-specific knock-in of miR-670-3p of the 5/6 nephrectomy with a high-phosphate diet (miR-670-3pEC-KI + NTP) mice that upregulated the level of miR-670-3p in artery tissues and significantly increased artery calcification. Finally, we validated that the level of circulation of plasma exosomal miR-670-3p was much higher in patients with ESRD compared with healthy controls. Elevated levels of plasma exosomal miR-670-3p were associated with a decline in IGF-1 and more severe artery calcification in patients with ESRD. Collectively, these findings suggested that ECs-derived exosomal miR-670-3p could promote arterial calcification by targeting IGF-1, which may serve as a potential therapeutic target for arterial calcification in ESRD patients.

Cellular Crosstalk in the Vascular Wall Microenvironment: The Role of Exosomes in Vascular Calcification.

Vascular calcification is prevalent in aging, diabetes, chronic kidney disease, cardiovascular disease, and certain genetic disorders. However, the pathogenesis of vascular calcification is not well-understood. It has been progressively recognized that vascular calcification depends on the bidirectional interactions between vascular cells and their microenvironment. Exosomes are an essential bridge to mediate crosstalk between cells and organisms, and thus they have attracted increased research attention in recent years. Accumulating evidence has indicated that exosomes play an important role in cardiovascular disease, especially in vascular calcification. In this review, we introduce vascular biology and focus on the crosstalk between the different vessel layers and how their interplay controls the process of vascular calcification.

H19 Promotes Osteoblastic Transition by Acting as ceRNA of miR-140-5p in Vascular Smooth Muscle Cells.

Arterial medial calcification is a common disease in patients with type 2 diabetes, end-stage renal disease and hypertension, resulting in high incidence and mortality of cardiovascular event. H19 has been demonstrated to be involved in cardiovascular diseases like aortic valve diseases. However, role of H19 in arterial medial calcification remains largely unknown. We identified that H19 was upregulated in ß-glycerophosphate (ß-GP) induced vascular smooth muscle cells (VSMCs), a cellular calcification model in vitro. Overexpression of H19 potentiated while knockdown of H19 inhibited osteogenic differentiation of VSMCs, as demonstrated by changes of osteogenic genes Runx2 and ALP as well as ALP activity. Notably, H19 interacted with miR-140-5p directly, as demonstrated by luciferase report system and RIP analysis. Mechanistically, miR-140-5p attenuated osteoblastic differentiation of VSMCs by targeting Satb2 and overexpression of miR-140-5p blocked H19 induced elevation of Satb2 as well as the promotion of osteoblastic differentiation of VSMCs. Interestingly, over-expression of Satb2 induced phosphorylation of ERK1/2 and p38MAPK. In conclusion, H19 promotes VSMC calcification by acting as competing endogenous RNA of miR-140-5p and at least partially by activating Satb2-induced ERK1/2 and p38MAPK signaling.

New Insights Into Implications of CTRP3 in Obesity, Metabolic Dysfunction, and Cardiovascular Diseases: Potential of Therapeutic Interventions.

Adipose tissue, as the largest endocrine organ, secretes many biologically active molecules circulating in the bloodstream, collectively termed adipocytokines, which not only regulate the metabolism but also play a role in pathophysiological processes. C1q tumor necrosis factor (TNF)-related protein 3 (CTRP3) is a member of C1q tumor necrosis factor-related proteins (CTRPs), which is a paralog of adiponectin. CTRP3 has a wide range of effects on glucose/lipid metabolism, inflammation, and contributes to cardiovascular protection. In this review, we comprehensively discussed the latest research on CTRP3 in obesity, diabetes, metabolic syndrome, and cardiovascular diseases.

The Suppression of miR-199a-3p by Promoter Methylation Contributes to Papillary Thyroid Carcinoma Aggressiveness by Targeting RAP2a and DNMT3a.

BACKGROUND: It was previously demonstrated that miR-199a-3p plays an important role in tumor progression; especially, its down-regulation in papillary thyroid cancer (PTC) is associated with cancer cell invasion and proliferation. In the present report, we investigated the mechanism involved in the down-regulation of miR-199a-3p in PTC and how miR-199a-3p regulates PTC invasion both in vivo and in vitro. METHODS: qRT-PCR and Western blot assays were used to determine the expression of the investigated genes. Bisulfite sequencing PCR was used to investigate miR-199a-3p methylation. The functions of miR-199a-3p were investigated by a series of in vitro and in vivo experiments. RESULTS: Our results showed hypermethylation of the miR-199a-3p promoter, which resulted in decreased miR-199a-3p expression both in PTC cell lines and PTC tissues. DNA-methyltransferase 3a (DNMT3a), a target gene of miR-199a-3p, was increased both in PTC cell lines and PTC tissues, while 5-aza-2'-deoxycytidine (methyltransferase-specific inhibitor) or knock-down using DNMT3a Small-Interfering RNA could restore the expression of miR-199a-3p, and the over-expression of miR-199a-3p could decrease the expression of DNMT3a; this suggests that miR-199a-3p/DNMT3a constructs a regulatory circuit in regulating miR-199a-3p/DNMT3a expression. Moreover, gain- and loss-of-function studies revealed that miR-199a-3p is involved in cancer cell migration, invasion, and growth. Meanwhile, we found that RAP2a was also a direct target of miR-199a-3p, which might mediate the tumor-growth-inhibiting effect of miR-199a-3p. To further confirm the tumor-suppressive properties of miR-199a-3p, stable overexpression of miR-199a-3p in a PTC cell line (BCPAP cells) was xenografted to athymic BALB/c nude mice, resulting in delayed tumor growth in vivo. In clinical PTC samples, the expression of RAP2a and DNMT3a was increased significantly, and the expression of RAP2a was inversely correlated with that of miR-199a-3p. CONCLUSION: Our studies demonstrate that an epigenetic change in the promoter region of miR-199a contributes to the aggressive behavior of PTC via the miR-199a-3p/DNMT3a regulatory circuit and directly targets RAP2a.

Adiponectin attenuates the premature senescence of vascular smooth muscle cells induced by high glucose through mTOR signaling pathway.

OBJECTIVE: Cardiovascular diseases and vascular aging are common in patients with diabetes. High glucose is a major cause of vascular aging and cardiovascular diseases. Premature senescence of vascular smooth muscle cells (VSMCs) is one of the main contributors to vascular aging. Adiponectin has been demonstrated to have an anti-aging effect. The present study explored the mechanisms by which adiponectin protects VSMCs against high-glucose-induced senescence. METHODS: Senescence-associated ß-galactosidase (SA-ß-gal) staining was used to detect senescence cells. Western blot was used for measuring protein levels. Flow cytometry was carried out to detect the cell cycle and telomeric repeat amplification protocol (TRAP)-polymerase chain reaction (PCR) silver staining was selected to measure the telomerase activity. RESULTS: Premature senescence of VSMCs was induced by high glucose (30 mM) in a time-dependent manner, which was verified by an increased number of senescence cells, p21 and p53 expression, as well as the decreased proliferation index. High glucose reduced telomerase activity of VSMCs via inhibition of the AMPK/TSC2/mTOR/S6K1 pathway and activation of the PI3K/Akt/mTOR/S6K1 pathway, while adiponectin treatment significantly increased telomerase activity of VSMCs through activation of AMPK/TSC2/mTOR/S6K1 signaling and inhibition of PI3K/Akt/mTOR/S6K1 signaling. CONCLUSION: Adiponectin attenuated the high-glucose-induced premature senescence of VSMCs via increasing telomerase activity of VSMCs, which was achieved by activation of AMPK/TSC2/mTOR/S6K1 signaling and inhibition of PI3K/Akt/mTOR/S6K1 signaling.

LncRNA-ES3 inhibition by Bhlhe40 is involved in high glucose-induced calcification/senescence of vascular smooth muscle cells.

Long noncoding RNAs (lncRNAs) have been investigated as novel regulatory molecules involved in diverse biological processes. Our previous study demonstrated that lncRNA-ES3 is associated with the high glucose-induced calcification/senescence of human aortic vascular smooth muscle cells (HA-VSMCs). However, the mechanism of lncRNA-ES3 in vascular calcification/aging remained largely unknown. Here, we report that the expression of basic helix-loop-helix family member e40 (Bhlhe40) was decreased significantly in HA-VSMCs treated with high glucose, whereas the expression of basic leucine zipper transcription factor (BATF) was increased. Overexpression of Bhlhe40 and inhibition of BATF alleviated calcification/senescence of HA-VSMCs, as confirmed by Alizarin Red S staining and the presence of senescence-associated ß-galactosidase-positive cells. Moreover, we identified that Bhlhe40 regulates lncRNA-ES3 in HA-VSMCs by binding to the promoter region of the lncRNA-ES3 gene (LINC00458). Upregulation or inhibition of lncRNA-ES3 expression significantly promoted or reduced calcification/senescence of HA-VSMCs, respectively. Additionally, we identified that lncRNA-ES3 functions in this process by suppressing the expression of miR-95-5p, miR-6776-5p, miR-3620-5p, and miR-4747-5p. The results demonstrate that lncRNA-ES3 triggers gene silencing of multiple miRNAs by binding to Bhlhe40, leading to calcification/senescence of VSMCs. Our findings suggest that pharmacological interventions targeting lncRNA-ES3 may be therapeutically beneficial in ameliorating vascular calcification/aging.

Exosomes as Mediators of Cell-to-Cell Communication in Thyroid Disease.

Exosomes are a type of extracellular vehicle, formed by budding cell membranes, containing proteins, DNA, and RNA. Concentrated cargoes from parent cells are enveloped in exosomes, which are cell specific and may have functions in the recipient cell, reflecting a novel physiological and pathological mechanism in disease development. As a transmitter, exosomes shuttle to different cells or tissues and mediate communications among these organelles. To date, several studies have demonstrated that exosomes play crucial roles in disease pathogenesis and development, such as breast and prostate cancer. However, studies investigating connections between exosomes and thyroid disease are limited. In this review, recent research advances on exosomes in thyroid cancer and Graves' disease are reviewed. These studies suggest that exosomes are involved in thyroid disease and appear as impressive potentials in thyroid therapeutic areas.

The Role of Substance P in the Regulation of Bone and Cartilage Metabolic Activity.

Substance P (SP) is a neuropeptide that is released from sensory nerve endings and is widely present in nerve fibers. It acts on bones and related tissues by binding to receptors, thereby regulating bone metabolism, cartilage metabolism, and fracture healing. SP has attracted widespread attention as a signaling substance that can be recognized by both the immune system and the nervous system. Previous studies have shown that bone and chondrocytes can synthesize and secrete sensory neuropeptides and express their receptors, and can promote proliferation, differentiation, apoptosis, matrix synthesis, and the degradation of target cells through autocrine/paracrine modes. In this paper, we review the research progress made in this field in recent years in order to provide a reference for further understanding the regulatory mechanism of bone and cartilage physiology and pathological metabolism.

Melatonin alleviates vascular calcification and ageing through exosomal miR-204/miR-211 cluster in a paracrine manner.

In the elderly with atherosclerosis, hypertension and diabetes, vascular calcification and ageing are ubiquitous. Melatonin (MT) has been demonstrated to impact the cardiovascular system. In this study, we have shown that MT alleviates vascular calcification and ageing, and the underlying mechanism involved. We found that both osteogenic differentiation and senescence of vascular smooth muscle cells (VSMCs) were attenuated by MT in a MT membrane receptor-dependent manner. Moreover, exosomes isolated from VSMCs or calcifying vascular smooth muscle cells (CVSMCs) treated with MT could be uptaken by VSMCs and attenuated the osteogenic differentiation and senescence of VSMCs or CVSMCs, respectively. Moreover, we used conditional medium from MT-treated VSMCs and Transwell assay to confirm exosomes secreted by MT-treated VSMCs attenuated the osteogenic differentiation and senescence of VSMCs through paracrine mechanism. We also found exosomal miR-204/miR-211 mediated the paracrine effect of exosomes secreted by VSMCs. A potential target of these two miRs was revealed to be BMP2. Furthermore, treatment of MT alleviated vascular calcification and ageing in 5/6-nephrectomy plus high-phosphate diet-treated (5/6 NTP) mice, while these effects were partially reversed by GW4869. Exosomes derived from MT-treated VSMCs were internalised into mouse artery detected by in vivo fluorescence image, and these exosomes reduced vascular calcification and ageing of 5/6 NTP mice, but both effects were largely abolished by inhibition of exosomal miR-204 or miR-211. In summary, our present study revealed that exosomes from MT-treated VSMCs could attenuate vascular calcification and ageing in a paracrine manner through an exosomal miR-204/miR-211.

Plasma Exosomes Derived From Patients With End-Stage Renal Disease and Renal Transplant Recipients Have Different Effects on Vascular Calcification.

End-stage renal disease (ESRD) patients usually develop extensive and progressive vascular calcification, and lots of calcification inhibitors as well as procalcifying factors are involved in the process. However, the mechanisms of vascular calcification in ESRD patients are still ill-defined. In the present study, we found that the plasma exosomes derived from ESRD patients (ESRD-Ex) promoted calcification of vascular smooth muscle cells (VSMCs) significantly, while plasma exosomes from renal transplant recipients (RTR-Ex) could partially attenuate VSMCs calcification. Moreover, the protein concentration of ESRD-Ex was significantly higher than plasma exosomes from the normal health control group (Nor-Ex) and RTR-Ex, and the content of both matrix gla protein (MGP) and Fetuin-A, the calcification inhibitors, were prominently lower in ESRD-Ex than those in Nor-Ex. The content of Annexin-A2, one of the calcification promoters, was significantly higher in ESRD-Ex and RTR-Ex than that in Nor-Ex. However, bone morphogenetic protein (BMP-2) and receptor activator for nuclear factor-κB ligand (Rankl) had no significant difference among the three groups. In addition, the content of Fetuin-A in RTR-Ex was higher than that in ESRD-Ex, although it was still lower than that in Nor-Ex. Furthermore, the levels of both Fetuin-A and MGP in plasma exosomes were negatively while the levels of Annexin-A2 in plasma exosomes was positively correlated to coronary artery calcification scores (CACS). These results indicated that ESRD-Ex significantly promoted VSMCs calcification, while renal transplantation could partially attenuate the procalcification effect of exosomes. Fetuin-A and MGP were decreased, but Annexin-A2 was increased in ESRD-Ex, and renal transplantation could increase the level of Fetuin-A rather than MGP.

Exosomes and Bone Disease.

Exosomes, which mediate cell-to-cell communications and provide a novel insight into information exchange, have drawn increasing attention in recent years. The homeostasis of bone metabolism is critical for bone health. The most common bone diseases such as osteoporosis, osteoarthritis and bone fractures have apparent correlations with exosomes. Accumulating evidence has suggested the potential regenerative capacities of stem cell-derived exosomes. In this review, we summarise the pathophysiological mechanism, clinical picture and therapeutic effects of exosomes in bone metabolism. We introduce the advantages and challenges in the application of exosomes. Although the exact mechanisms remain unclear, miRNAs seem to play major roles in the exosome.

Role of tumor-derived exosomes in bone metastasis.

Tight coupling between bone resorption and formation is essential for bone remodeling. Disruption of this equilibrium can lead to skeletal disorders. Osseous metastatic disease is a severe consequence of tumor cell dissemination from numerous primary cancer sites, including the prostate, lungs and breasts. Metastatic disease is one of the most common causes of mortality in patients with cancer. Rapid advances in the therapeutic options for bone disease, including the use of bisphosphonates, have achieved effective clinical effects. However, the overall survival time of patients with bone metastatic has not significantly improved. Exosomes, which originate from tumor tissue and preferentially the bone, provide a reasonable way to understand the mechanism of neoplastic bone metastasis. Recently, several studies have indicated that tumor-derived exosomes are involved in cancer progression. However, the potential role that exosomes serve in the pathological communication between tumor and bone cells within the skeletal microenvironment remains an emerging field. The present review reports some recent findings on the detrimental roles of exosomes in bone metastasis. In addition, since exosomes are involved in metabolic organ cross-talk, this review highlights the involvement of cancer-derived exosomes in the regulation of skeletal metastatic diseases. Lastly, the potential promising clinical applications and emerging therapeutic opportunities targeting exosomes are discussed as novel strategies for cancer therapy.

Adipose tissue-derived omentin-1 attenuates arterial calcification via AMPK/Akt signaling pathway.

Adipose tissue-derived adipokines mediate various kind of crosstalk between adipose tissue and other organs and thus regulate metabolism balance, inflammation state as well as disease progression. In particular, omentin-1, a newly found adipokine, has been reported to exhibit anti-calcification effects in vitro and in vivo. However, little is known about the function of endogenous adipose tissue-derived omentin-1 in arterial calcification and the detailed mechanism involved. Here, we demonstrated that global omentin-1 knockout (omentin-1-/-) resulted in more obvious arterial calcification in 5/6-nephrectomy plus high phosphate diet treated (5/6 NTP) mice while overexpression of omentin-1 attenuated attenuates osteoblastic differentiation and mineralisation of VSMCs in vitro and 5/6 NTP-induced mice arterial calcification in vivo. Moreover, we found that omentin-1 induced AMPK and Akt activation while inhibition of AMP-activated protein kinase (AMPK) and Akt signaling reversed the anti-calcification effect induced by omentin-1 both in vitro and in vivo. Our results suggest that adipose tissue-derived omentin-1 serves as a potential therapeutic target for arterial calcification and cardiovascular disease.

Aberrant DNA methylation of synaptophysin is involved in adrenal cortisol-producing adenoma.

Cortisol-producing adenoma (CPA) is the main cause of Adrenal Cushing syndrome. However, its molecular mechanism is not fully understood. Previous study revealed Synaptophysin (SYP) is ubiquitously expressed in adrenocortical tumors, but its function in CPA still need to be discovered. In the present study we determine the molecular mechanism involved in SYP dysregulation in CPA and how SYP affects the secretion of cortisol in CPA. Our results showed that aberrant DNA methylation of SYP is involved in CPA progress. Using a miRNA microarray and qRT-PCR, we found decreased expression of miR-27a-5p in CPA compared with normal adrenal tissue. Moreover, the expression of TET3, the target gene of miR-27a-5p, increased in CPA compared with normal adrenal tissue. Knock-down of TET3 resulted in hypermethylation of SYP which reducing the expression level of SYP in H295R cells. The miR-27a-5p-TET3-SYP signalling pathway may regulate proliferation and cortisol secretion in H295R cells and, thus, play a key role in CPA development.

Exosomal Notch3 from high glucose-stimulated endothelial cells regulates vascular smooth muscle cells calcification/aging.

AIMS: Vascular calcification/aging can cause different kind of serious diabetic vascular complications. High glucose could induce vascular smooth muscle cells (VSMCs) calcification/aging and then lead to diabetes-related vascular calcification/aging. In this study, we investigated how information in the blood is transmitted to VSMCs and the mechanisms of VSMCs calcification/aging under hyperglycaemic conditions. MATERIALS AND METHODS: Transmission electron microscopy and molecular size analysis were used to assess the morphology and size of exosomes. Alizarin Red S staining and senescence-associated ß galactosidase (SA-ß-gal) staining were carried out to detect calcification and senescence in VSMCs, respectively. Proteomics analysis was carried out to detect the different expression of exosomal proteins. Protein levels were measured by western blot analysis. KEY FINDINGS: The results show that exosomes isolated from high glucose stimulated human umbilical vein endothelial cell (HG-HUVEC-Exo) exhibited a bilayer structure morphology with a mean diameter of 63.63 ±â€¯2.96 nm. The presence of exosome markers including CD9, CD63 and TSG101 were also detected in HG-HUVEC-Exo. High glucose could induce VSMCs calcification/aging by increasing the expression of osteocalcin (OC) and p21 as well as the formation of mineralised nodules and SA-ß-gal positive cells. Fluorescence microscopy verified that the exosomes were taken up by VSMCs and Notch3 protein was enriched in HG-HUVEC-Exo. Most importantly, mTOR signalling was closely related to Notch3 protein and was involved in regulating HG-HUVEC-Exo-induced VSMCs calcification/aging. SIGNIFICANCE: The data demonstrate that Notch3 is required for HG-HUVEC-Exo promoted VSMCs calcification/aging and regulates VSMCs calcification/aging through the mTOR signalling pathway.

Aberration methylation of miR-34b was involved in regulating vascular calcification by targeting Notch1.

Vascular calcification is one of the most important factors for cardiovascular and all-cause mortality in patients with end-stage renal diseases (ESRD). The current study was aimed to investigate the function and mechanisms of miR-34b on the calcification of vascular smooth muscle cells (VSMCs) both in vitro and in vivo. We found that the expression of miR-34b was significantly suppressed in VSMCs with high inorganic phosphate (Pi) treatment, as well as mouse arteries derived from 5/6 nephrectomy with a high-phosphate diet (0.9% Pi, 5/6 NTP) and human renal arteries from uraemia patients. Overexpression of miR-34b alleviated calcification of VSMCs, while VSMCs calcification was enhanced by inhibiting the expression of miR-34b. Bisulphite sequencing PCR (BSP) uncovered that CpG sites upstream of miR-34b DNA were hypermethylated in calcified VSMCs and calcified arteries due to 5/6 NTP, as well as calcified renal arterial tissues from uraemia patients. Meantime, increased DNA methyltransferase 3a (DNMT3a) resulted in the hypermethylation of miR-34b in VSMCs, while 5-aza-2'-deoxycytidine (5-aza) reduced the methylation rate of miR-34b and restored the expression of miR-34b in VSMCs. When DNMT3a was knocked down using DNMT3a siRNA, the effect of 3.5 mM of Pi on calcification of VSMCs was abrogated. In addition, Notch1 was validated as the functional target of miR-34b and involved in the process of calcification of VSMCs. Taken together, our data showed a specific role for miR-34b in regulating calcification of VSMCs both in vitro and in vivo, which was regulated by upstream DNA methylation of miR-34b and modulated by the downstream target gene expression, Notch1. These results suggested that modulation of miR-34b may offer new insight into a novel therapeutic approach for vascular calcification.

Exosomes increased angiogenesis in papillary thyroid cancer microenvironment.

Tumour-derived exosomes under hypoxic conditions contain informative miRNAs involved in the interaction of cancer and para-carcinoma cells, thus contributing to tissue remodelling of the tumour microenvironment (TME). Exosomes isolated from hypoxic papillary thyroid cancer cells, BCPAP cells and KTC-1 cells enhanced the angiogenesis of human umbilical vein endothelial cells (HUVECs) compared with exosomes isolated from normal thyroid follicular cell line (Nthy-ori-3-1), normoxic BCPAP or KTC-1 cells both in vitro and in vivo. miR-21-5p was significantly upregulated in exosomes from papillary thyroid cancer BCPAP cells under hypoxic conditions, while the exosomes isolated from hypoxic BCPAP cells with knockdown of miR-21-5p attenuated the promoting effect of angiogenesis. In addition, our experiment revealed that miR-21-5p directly targeted and suppressed TGFBI and COL4A1, thereby increasing endothelial tube formation. Furthermore, elevated levels of exosomal miR-21-5p are found in the sera of papillary thyroid cancer patients, which promote the angiogenesis of HUVECs. Taken together, our study reveals the cell interaction between hypoxic papillary thyroid cancer cells and endothelial cells, elucidating a new mechanism by which hypoxic papillary thyroid cancer cells increase angiogenesis via exosomal miR-21-5p/TGFBI and miR-21-5p/COL4A1 regulatory pathway.

miR­124 regulates the osteogenic differentiation of bone marrow­derived mesenchymal stem cells by targeting Sp7.

MicroRNAs (miRNAs) are novel key regulators of cellular differentiation. miR­124 has been reported to regulate osteogenic differentiation of bone marrow­derived mesenchymal stem cells (BMSCs). However, the specific mechanisms involved have not yet been fully elucidated. The present study aimed to investigate the effect of miR­124 on osteogenic differentiation of BMSCs and its underlying mechanisms. In the present study, it was found that alkaline phosphatase (ALP) activity, osteocalcin (OC) secretion, and the protein levels of osterix (Sp7) and runt­related transcription factor 2 (Runx2) were significantly increased, whereas the expression of miR­124 was decreased in a time­dependent manner during osteogenic differentiation of BMSCs. Following overexpression of miR­124 via transfection of miR­124 mimics in BMSCs, Runx2 protein expression and ALP activity were significantly decreased. By contrast, inhibition of miR­124 expression led to an increase in ALP activity and Runx2 expression. Sp7 expression was suppressed in BMSCs transfected with miR­124 mimics while increased when miR­124 expression was inhibited, indicating that miR­124 regulates the expression of Sp7. Moreover, a luciferase reporter assay further verified that Sp7 is the direct target of miR­124. Finally, the effect of miR­124 inhibitor on promoting the differentiation of BMSCs was abolished following treatment with a small interfering RNA targeting Sp7. Taken together, the present study demonstrates that miR­124 inhibits the osteogenic differentiation of BMSCs by targeting Sp7.