Receptors that bind to PEDF and their therapeutic roles in retinal diseases

PEDF peptide plus hyaluronic acid stimulates cartilage regeneration in osteoarthritis via STAT3-mediated chondrogenesis

Aims

Pigment epithelium-derived factor (PEDF) is known to induce several types of tissue regeneration by activating tissue-specific stem cells. Here, we investigated the therapeutic potential of PEDF 29-mer peptide in the damaged articular cartilage (AC) in rat osteoarthritis (OA).

Methods

Mesenchymal stem/stromal cells (MSCs) were isolated from rat bone marrow (BM) and used to evaluate the impact of 29-mer on chondrogenic differentiation of BM-MSCs in culture. Knee OA was induced in rats by a single intra-articular injection of monosodium iodoacetate (MIA) in the right knees (set to day 0). The 29-mer dissolved in 5% hyaluronic acid (HA) was intra-articularly injected into right knees at day 8 and 12 after MIA injection. Subsequently, the therapeutic effect of the 29-mer/HA on OA was evaluated by the Osteoarthritis Research Society International (OARSI) histopathological scoring system and changes in hind paw weight distribution, respectively. The regeneration of chondrocytes in damaged AC was detected by dual-immunostaining of 5-bromo-2'-deoxyuridine (BrdU) and chondrogenic markers.

Results

The 29-mer promoted expansion and chondrogenic differentiation of BM-MSCs cultured in different defined media. MIA injection caused chondrocyte death throughout the AC, with cartilage degeneration thereafter. The 29-mer/HA treatment induced extensive chondrocyte regeneration in the damaged AC and suppressed MIA-induced synovitis, accompanied by the recovery of cartilage matrix. Pharmacological inhibitors of PEDF receptor (PEDFR) and signal transducer and activator of transcription 3 (STAT3) signalling substantially blocked the chondrogenic promoting activity of 29-mer on the cultured BM-MSCs and injured AC.

Conclusion

The 29-mer/HA formulation effectively induces chondrocyte regeneration and formation of cartilage matrix in the damaged AC.

Expression and significance of pigment epithelium-derived factor and vascular endothelial growth factor in colorectal adenoma and cancer

BACKGROUND

The incidence and mortality of colorectal cancer (CRC) are among the highest in the world, and its occurrence and development are closely related to tumor neovascularization. When the balance between pigment epithelium-derived factors (PEDF) that inhibit angiogenesis and vascular endothelial growth factors (VEGF) that stimulate angiogenesis is broken, angiogenesis is out of control, resulting in tumor development. Therefore, it is very necessary to find more therapeutic targets for CRC for early intervention and later treatment.

AIM

To investigate the expression and significance of PEDF, VEGF, and CD31-stained microvessel density values (CD31-MVD) in normal colorectal mucosa, adenoma, and CRC.

METHODS

In this case-control study, we collected archived wax blocks of specimens from the Digestive Endoscopy Center and the General Surgery Department of Chengdu Second People's Hospital from April 2022 to October 2022. Fifty cases of specimen wax blocks were selected as normal intestinal mucosa confirmed by electronic colonoscopy and concurrent biopsy (normal control group), 50 cases of specimen wax blocks were selected as colorectal adenoma confirmed by electronic colonoscopy and pathological biopsy (adenoma group), and 50 cases of specimen wax blocks were selected as CRC confirmed by postoperative pathological biopsy after inpatient operation of general surgery (CRC group). An immunohistochemical staining experiment was carried out to detect PEDF and VEGF expression in three groups of specimens, analyze their differences, study the relationship between the two and clinicopathological factors in CRC group, record CD31-MVD in the three groups, and analyze the correlation of PEDF, VEGF, and CD31-MVD in the colorectal adenoma group and the CRC group. The F test or adjusted F test is used to analyze measurement data statistically. Kruskal-Wallis rank sum test was used between groups for ranked data. The chi-square test, adjusted chi-square test, or Fisher's exact test were used to compare the rates between groups. All differences between groups were compared using the Bonferroni method for multiple comparisons. Spearman correlation analysis was used to test the correlation of the data. The test level (α) was 0.05, and a two-sided P< 0.05 was considered statistically significant.

RESULTS

The positive expression rate and expression intensity of PEDF were gradually decreased in the normal control group, adenoma group, and CRC group (100% vs 78% vs 50%, χ2 = 34.430, P < 0.001; ++~++ vs +~++ vs -~+, H = 94.059, P < 0.001), while VEGF increased gradually (0% vs 68% vs 96%, χ2 = 98.35, P < 0.001; - vs -~+ vs ++~+++, H = 107.734, P < 0.001). In the CRC group, the positive expression rate of PEDF decreased with the increase of differentiation degree, invasion depth, lymph node metastasis, distant metastasis, and TNM stage (χ2 = 20.513, 4.160, 5.128, 6.349, 5.128, P < 0.05); the high expression rate of VEGF was the opposite (χ2 = 10.317, 13.134, 17.643, 21.844, 17.643, P < 0.05). In the colorectal adenoma group, the expression intensity of PEDF correlated negatively with CD31-MVD (r = -0.601, P < 0.001), whereas VEGF was not significantly different (r = 0.258, P = 0.07). In the CRC group, the expression intensity of PEDF correlated negatively with the expression intensity of CD31-MVD and VEGF (r = -0.297, P < 0.05; r = -0.548, P < 0.05), while VEGF expression intensity was positively related to CD31-MVD (r = 0.421, P = 0.002).

CONCLUSION

It is possible that PEDF can be used as a new treatment and prevention target for CRC by upregulating the expression of PEDF while inhibiting the expression of VEGF.

What factors may affect the effect of ICI-combined therapy in patients with metastatic renal cell carcinoma? A meta-analysis

Objective: The prognostic factors of ICI-including combined therapy in patients with metastatic renal cell carcinoma were analyzed by systematic review.Method: We searched Web of Science, Cochrane, PubMed, CNKI, Wanfang and other databases for randomized controlled trials and clinical trials of combination therapy including ICIs in the treatment of metastatic renal cell carcinoma. The search time was from the establishment of the database to September 2023. Data were extracted and evaluated with RevMan 5.4 software.Results: Six studies were included, including 4723 patients. The results showed that ① in terms of progression-free survival, the factors of age < 65 years old, male sex, Canada and Western Europe, nephrectomy, different IMDC class, number of organs with metastases and PD-L1 expression ≥ 1% significantly prolonged PFS in patients with metastatic cancer treated by combination therapy including ICIs; ② in terms of overall survival rate, the factors of age < 65 years old, female sex, nephrectomy, different IMDC class and PD-L1 expression ≥ 1% significantly prolonged the OS of patients with metastatic cancer treated by combination therapy including ICIs.Conclusions: Age, sex, region, nephrectomy, different IMDC class, number of organs with metastases and PD-L1 expression are independent factors influencing the efficacy of combination therapy including ICIs in the treatment of metastatic renal cell carcinoma. Systematic evaluation of baseline indicators of patients with metastatic renal cell carcinoma to predict clinical benefits can effectively improve the benefit rate of patients.

The Various Roles of PEDF in Cancer

Pigment epithelium-derived factor (PEDF) is a natural immunomodulator, anti-inflammatory, anti-angiogenic, anti-tumour growth and anti-metastasis factor, which can enhance tumour response to PEDF but can also conversely have pro-cancerous effects. Inflammation is a major cause of cancer, and it has been proven that PEDF has anti-inflammatory properties. PEDF's functional activity can be investigated through measuring metastatic and metabolic biomarkers that will be discussed in this review.

Relationship between Biochemical Pathways and Non-Coding RNAs Involved in the Progression of Diabetic Retinopathy

Diabetic retinopathy (DR) is a progressive blinding disease, which affects the vision and quality of life of patients, and it severely impacts the society. This complication, caused by abnormal glucose metabolism, leads to structural, functional, molecular, and biochemical abnormalities in the retina. Oxidative stress and inflammation also play pivotal roles in the pathogenic process of DR, leading to mitochondrial damage and a decrease in mitochondrial function. DR causes retinal degeneration in glial and neural cells, while the disappearance of pericytes in retinal blood vessels leads to alterations in vascular regulation and stability. Clinical changes include dilatation and blood flow changes in response to the decrease in retinal perfusion in retinal blood vessels, leading to vascular leakage, neovascularization, and neurodegeneration. The loss of vascular cells in the retina results in capillary occlusion and ischemia. Thus, DR is a highly complex disease with various biological factors, which contribute to its pathogenesis. The interplay between biochemical pathways and non-coding RNAs (ncRNAs) is essential for understanding the development and progression of DR. Abnormal expression of ncRNAs has been confirmed to promote the development of DR, suggesting that ncRNAs such as miRNAs, lncRNAs, and circRNAs have potential as diagnostic biomarkers and theranostic targets in DR. This review provides an overview of the interactions between abnormal biochemical pathways and dysregulated expression of ncRNAs under the influence of hyperglycemic environment in DR.