TGFβ1 induces in-vitro and ex-vivo angiogenesis through VEGF production in human ovarian follicular fluid-derived granulosa cells during in-vitro fertilization cycle

The Presence of TGFβ3 in Human Ovarian Intrafollicular Fluid and Its Involvement in Thromboxane Generation in Follicular Granulosa Cells through a Canonical TGFβRI, Smad2/3 Signaling Pathway and COX-2 Induction

Ovarian follicular fluid (FF) has a direct impact on oocyte quality, playing key roles in fertilization, implantation, and early embryo development. In our recent study, we found FF thromboxane (TX) to be a novel factor inversely correlated with oocyte maturation and identified thrombin, transforming growth factor β (TGFβ), TNF-α, and follicular granulosa cells (GCs) as possible contributors to FF TX production. Therefore, this study sought to investigate the role of TGFβ3 in regulating TX generation in human ovarian follicular GCs. TGFβ3 was differentially and significantly present in the FF of large and small follicles obtained from IVF patients with average concentrations of 68.58 ± 12.38 and 112.55 ± 14.82 pg/mL, respectively, and its levels were correlated with oocyte maturity. In an in vitro study, TGFβ3 induced TX generation/secretion and the converting enzyme-COX-2 protein/mRNA expression both in human HO23 and primary cultured ovarian follicular GCs. While TGFβRI and Smad2/3 signaling was mainly required for COX-2 induction, ERK1/2 appeared to regulate TX secretion. The participation of Smad2/3 and COX-2 in TGFβ3-induced TX generation/secretion could be further supported by the observations that Smad2/3 phosphorylation and nuclear translocation and siRNA knockdown of COX-2 expression compromised TX secretion in GCs challenged with TGFβ3. Taken together, the results presented here first demonstrated that FF TGFβ3 levels differ significantly in IVF patients' large preovulatory and small mid-antral follicles and are positively associated with oocyte maturation. TGFβ3 can provoke TX generation by induction of COX-2 mRNA/protein via a TGFβR-related canonical Smad2/3 signaling pathway, and TX secretion possibly by ERK1/2. These imply that TGFβ3 is one of the inducers for yielding FF TX in vivo, which may play a role in folliculogenesis and oocyte maturation.

Factors associated with the efficacy of mature oocyte production after dual-trigger controlled ovarian stimulation using a GnRH antagonist protocol

BACKGROUND

The number of mature oocytes retrieved plays a significant role in determining embryo development and pregnancy outcomes of in vitro fertilization (IVF). However, studies investigating factors predictive of the efficacy of mature oocyte production (EMOP) after dual-trigger controlled ovarian stimulation (COS) are rare. This study aims to identify key predictors of EMOP during dual-trigger COS with a gonadotropin-releasing hormone (GnRH) antagonist protocol for IVF.

METHODS

This retrospective cohort study included 359 first-time IVF patients undergoing dual-trigger COS with a GnRH antagonist protocol. EMOP was defined as the ratio of metaphase II (MII) oocyte count to antral follicle count (AFC). Based on EMOP results, patients were divided into two groups: group A (EMOP <70%; n = 232) and group B (EMOP ≥70%; n = 127).

RESULTS

Multivariate logistic regression analysis revealed that day-2 follicle-stimulating hormone (FSH), stimulation duration, and total oocyte count were the most significant predictors of EMOP ( p < 0.05; odds ratios: 1.637, 3.400, and 1.530, respectively). Receiver operating characteristic analysis demonstrated that total oocyte count <9.5 (area under the curve [AUC], 0.782; sensitivity, 76.2%; specificity, 69.2%; p < 0.001) and stimulation duration <9.5 days (AUC, 0.725; sensitivity, 63.5%; specificity, 66.7%; p < 0.001) significantly predicted EMOP <70%. Stimulation duration combined with total oocyte count exhibited the highest power in predicting EMOP <70% (AUC, 0.767; sensitivity, 92.3%; specificity, 42.4%).

CONCLUSION

Stimulation duration combined with total oocyte count was identified as the most important factor associated with the EMOP during dual-trigger COS in IVF using a GnRH antagonist protocol.

Identification of potential angiogenic biomarkers in human follicular fluid for predicting oocyte maturity

Background

Angiogenesis in folliculogenesis contributes to oocyte developmental competence in natural and in vitro fertilization (IVF) cycles. Therefore, the identification of key angiogenic factors in follicular fluid (FF) during folliculogenesis is clinically significant and important for in vitro fertilization. This study aims to identify the key angiogenic factors in FF for predicting oocyte maturity during in vitro fertilization.

Materials and methods

Forty participants who received ovarian stimulation using a GnRH antagonist protocol in their first in vitro fertilization treatment were recruited. From each patient, two follicular samples (one preovulatory follicle, > 18 mm; one mid-antral follicle, < 14 mm) were collected without flushing during oocyte retrieval. In total, 80 FF samples were collected from 40 patients. The expression profiles of angiogenesis-related proteins in FF were analyzed via Luminex high-performance assays. Recorded patient data included antral follicle count, anti-müllerian hormone, age, and BMI. Serum samples were collected on menstrual cycle day 2, the trigger day, and the day of oocyte retrieval. Hormone concentrations including day 2 FSH/LH/E2/P4, trigger day E2/LH/P4, and retrieval day E2/LH/P4 were measured by chemiluminescence assay.

Results

Ten angiogenic factors were highly expressed in FF: eotaxin, Gro-α, IL-8, IP-10, MCP-1, MIG, PAI-1 (Serpin), VEGF-A, CXCL-6, and HGF. The concentrations of eotaxin, IL-8, MCP1, PAI-1, and VEGF-A were significantly higher in preovulatory follicles than those in mid-antral follicles, while the Gro-α and CXCL-6 expressional levels were lower in preovulatory than in mid-antral follicles (p < 0.05). Logistic regression and receiver operating characteristic (ROC) analysis revealed that VEGF-A, eotaxin, and CXCL-6 were the three strongest predictors of oocyte maturity. The combination of VEGF-A and CXCL-6 predicted oocyte maturity with a higher sensitivity (91.7%) and specificity (72.7%) than other combinations.

Conclusion

Our findings suggest that VEGF-A, eotaxin, and CXCL-6 concentrations in FF strongly correlate with oocyte maturity from the mid-antral to preovulatory stage. The combination of VEGF-A and CXCL-6 exhibits a relatively good prediction rate of oocyte maturity during in vitro fertilization.

1α,25-Dihydroxyvitamin D3 Promotes Angiogenesis After Cerebral Ischemia Injury in Rats by Upregulating the TGF-β/Smad2/3 Signaling Pathway

Stroke is a disease with high morbidity, disability and mortality, which seriously endangers the life span and quality of life of people worldwide. Angiogenesis and neuroprotection are the key to the functional recovery of penumbra function after acute cerebral infarction. In this study, we used the middle cerebral artery occlusion (MCAO) model to investigate the effects of 1α,25-dihydroxyvitamin D3 (1,25-D3) on transforming growth factor-β (TGF-β)/Smad2/3 signaling pathway. Cerebral infarct volume was measured by TTC staining. A laser speckle flow imaging system was used to measure cerebral blood flow (CBF) around the ischemic cortex of the infarction, followed by platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) and isolectin-B4 (IB4) immunofluorescence. The expression of vitamin D receptor (VDR), TGF-β, Smad2/3, p-Smad2, p-Smad3, and vascular endothelial growth factor (VEGF) was analyzed by western blot and RT-qPCR. Results showed that compared with the sham group, the cerebral infarction volume was significantly increased while the CBF was reduced remarkably in the MCAO group. 1,25-D3 reduced cerebral infarction volume, increased the recovery of CBF and expressions of VDR, TGF-β, p-Smad2, p-Smad3, and VEGF, significantly increased IB4⁺ tip cells and CD31⁺ vascular length in the peri-infarct area compared with the DMSO group. The VDR antagonist pyridoxal-5-phosphate (P5P) partially reversed the neuroprotective effects of 1,25-D3 described above. In summary, 1,25-D3 plays a neuroprotective role in stroke by activating VDR and promoting the activation of TGF-β, which in turn up-regulates the TGF-β/Smad2/3 signaling pathway, increases the release of VEGF and thus promotes angiogenesis, suggesting that this signaling pathway may be an effective target for ischemic stroke treatment. 1,25-D3 is considered to be a neuroprotective agent and is expected to be an effective drug for the treatment of ischemic stroke and related diseases.

Ginsenoside PPD inhibit the activation of HSCs by directly targeting TGFβR1

TGFβ1 signaling pathway is associated with many diseases, which can induce the activation of hepatic stellate cells (HSCs) and induce liver fibrosis. Studies have shown that 20S-protopanaxadiol (PPD) has a therapeutic effect on liver fibrosis, but the target is unknown. In this study, we confirmed that PPD reduced the mRNA expression of downstream genes of the TGFβ1 pathway, which suggesting PPD is associated with the TGFβ1 pathway. The protein dissociation temperature and dissociation constant (Kd) of PPD on TGFβR1 and TGFβR2 were determined, which showed that PPD combined with TGFβR1 (Kd = 1.54 μM). The docking and simulation methods were used to find their binding sites. Site mutations, protein expression and in vitro binding experiments were performed to demonstrated these sites. In particular, these sites of TGFβR1 were also the active sites of TGFβR2. Therefore, we speculated that PPD blocked the combination of TGFβR1 and TGFβR2 by binding to the D57, R58, P59, and N78 of the TGFβR1 extracellular domain. Thus, PPD could block the transmission of TGFβ1 pathway and inhibit the activation of HSCs, and treating fibrosis. Our studies showed that PPD has the potential to treat diseases related to the TGFβ1 pathway and broadens its clinical application.