Evidence That DDR1 Promotes Oligodendrocyte Differentiation during Development and Myelin Repair after Injury.

Oligodendrocytes generate myelin sheaths vital for the formation, health, and function of the central nervous system. Mounting evidence suggests that receptor tyrosine kinases (RTKs) are crucial for oligodendrocyte differentiation and myelination in the CNS. It was recently reported that discoidin domain receptor 1 (Ddr1), a collagen-activated RTK, is expressed in oligodendrocyte lineage. However, its specific expression stage and functional role in oligodendrocyte development in the CNS remain to be determined. In this study, we report that Ddr1 is selectively upregulated in newly differentiated oligodendrocytes in the early postnatal CNS and regulates oligodendrocyte differentiation and myelination. Ddr1 knock-out mice of both sexes displayed compromised axonal myelination and apparent motor dysfunction. Ddr1 deficiency alerted the ERK pathway, but not the AKT pathway in the CNS. In addition, Ddr1 function is important for myelin repair after lysolecithin-induced demyelination. Taken together, the current study described, for the first time, the role of Ddr1 in myelin development and repair in the CNS, providing a novel molecule target for the treatment of demyelinating diseases.

Expression of CD22 in Triple-Negative Breast Cancer: A Novel Prognostic Biomarker and Potential Target for CAR Therapy.

Triple-negative breast cancer (TNBC) accounts for 15-20% of all breast cancer cases. Due to the lack of expression of well-known molecular targets [estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2)], there is a need for more alternative treatment approaches in TNBC. Chimeric antigen receptor (CAR)-T cell-based immunotherapy treatment is one of the latest treatment technologies with outstanding therapeutic advances in the past decade, especially in the treatment of hematologic malignancies, but the therapeutic effects of CAR-T cells against solid tumors have not yet shown significant clinical benefits. Identification of highly specific CAR-T targets in solid tumors is also crucial for its successful treatment. CD22 is reported to be a multifunctional receptor that is mainly expressed on the surface of mature B-cells (lymphocytes) and is also highly expressed in most B-cell malignancies. This study aimed to investigate the expression of CD22 in TNBC. Bioinformatic analysis was performed to evaluate the expression of CD22 in breast carcinoma and normal tissues. RNA-seq data of normal and breast carcinoma patients were downloaded from The Cancer Genome Atlas (TCGA), and differential gene expression was performed using R language. Additionally, online bioinformatics web tools (GEPIA and TNM plot) were used to evaluate the expression of CD22 in breast carcinoma and normal tissues. Western blot (WB) analysis and immunofluorescence (IF) were performed to characterize the expression of CD22 in TNBC cell lines. Immunohistochemical (IHC) staining was performed on tumor specimens from 97 TNBC patients for CD22 expression. Moreover, statistical analysis was performed to analyze the association of clinical pathological parameters with CD22 expression. Correlation analysis between overall survival data of TNBC patients and CD22 expression was also performed. Differential gene expression analysis of TCGA data revealed that CD22 is among the upregulated differentially expressed genes (DEGs) with high expression in breast cancer, as compared to normal breast tissues. WB and IF analysis revealed high expression of CD22 in TNBC cell lines. IHC results also showed that approximately 62.89% (61/97) of TNBC specimens were stained positive for CD22. Cell membrane expression of CD22 was evident in 23.71% (23/97) of TNBC specimens, and 39.18% (38/97) of TNBC specimens showed cytoplasmic/membrane expression, while 37.11% (36/97) specimens were negative for CD22. Furthermore, significant associations were found between the size of tumors in TNBC patients and CD22 expression, which unveils its potential as a prognostic biomarker. No significant correlation was found between the overall survival of TNBC patients and CD22 expression. In conclusion, we demonstrated for the first time that CD22 is highly expressed in TNBC. Based on our findings, we anticipated that CD22 could be used as a prognostic biomarker in TNBC, and it might be a potential CAR-T target in TNBC for whom few therapeutic options exist. However, more large-scale studies and clinical trials will ensure its potential usefulness as a CAR-T target in TNBC.

Emerging Technologies for the Detection of Cancer Micrometastasis.

The most efficient way to treat tumors is through surgery. However, many cancer patients have a poor prognosis even when they undergo radical excision at an early stage. Micrometastasis is one of the most critical factors that induced this situation. Undetected micrometastasis can lead to the failure of initial treatment. Therefore, preoperative and intraoperative detection of micrometastasis could have a significant clinical influence on the prognosis and optimal therapy for cancer patients. Additionally, to achieve this goal, researchers have aimed to create more effective detection technologies. Herein, we classify the currently reported micrometastasis detection technologies, introduce some representative samples for each technology, including the limitations, and provide future directions to overcome the limitations.

Identification of Genes Related to 5-Fluorouracil Based Chemotherapy for Colorectal Cancer.

Background: Colorectal cancer (CRC) is one of the most common malignancies and its incidence and mortality are increasing yearly. 5-Fluorouracil (5-FU) has long been used as a standard first-line treatment for CRC patients. Although 5-FU-based chemotherapy is effective for advanced CRC, the consequent resistance remains a key problem and causes the poor prognosis of CRC patients. Thus, there is an urgent need to identify new biomarkers to predict the response to 5-FU-based chemotherapy. Methods: CRC samples were retrieved from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). The immune-related genes were retrieved from the ImmPort database. Single-cell sequencing results from colorectal cancer were obtained by the ArrayExpress database. 5-FU resistance-related genes were filtered and validated by R packages. ESTIMATE algorithms were used to assess the tumor microenvironment (TME). KEGG and GO analysis were performed to explore the biological signaling pathway for resistant-response patients and sensitive-response patients in the tumor microenvironment. pRRophetic algorithms were used to predict 5-FU sensitivity. GSEA and GSVA analysis was performed to excavate the biological signaling pathway of the RBP7 gene. Results: Nine immune-related genes were identified to be associated with 5-FU resistance and poor disease-free survival (DFS) of CRC patients and the signature of these genes was developed in a DFS-prognostic model. Four immune-related genes were determined to be associated with 5-FU resistance and overall survival (OS) of CRC patients. The signature of these genes was developed an OS-prognostic model. ESTIMATE scores showed a significant difference between 5-FU resistant and 5-FU sensitive CRC patients. Resistant-response patients and sensitive-response patients to 5-FU based chemotherapy showed different GO and KEGG enrichment on the tumor microenvironment. RBP7, as a tumor immune microenvironment (TIME) related gene, was found to have the potential of predicting chemotherapy resistance and poor prognosis of CRC patients. GSEA analysis showed multiple signaling differences between the high and low expression of RBP7 in CRC patients. Hypoxia and TNFα signaling via NFκB gene sets were significantly different between chemotherapy resistant (RBP7High) and chemotherapy sensitive (RBP7Low) patients. Single-cell RNA-seq suggested RBP7 was centrally distributed in endothelial stalk cells, endothelial tip cells, and myeloid cells. Conclusions: Immune-related genes will hopefully be potential prognostic biomarkers to predict chemotherapy resistance for CRC. RBP7 may function as a tumor microenvironment regulator to induce 5-FU resistance, thereby affecting the prognosis of CRC patients.

A Novel Diagnostic and Therapeutic Strategy for Cancer Patients by Integrating Chinese Medicine Syndrome Differentiation and Precision Medicine.

Applying Chinese medicine (CM) is an important strategy for malignant tumor treatment in China. One of the significant characteristics of CM is to treat diseases based on syndrome differentiation. For Western medicine, it is of important clinical significance to formulate guidelines for the diagnosis and treatment of cancer patients based on the characteristics of disease differentiation. In Chinese clinical practice, the combination of disease differentiation and syndrome differentiation is an important feature for cancer treatment in the past. Currently, molecular profiling and genomic analysis-based precision medicine optimizes the anticancer drug design and holds the greatest success in treating cancer patients. Therefore, we want to know which populations of cancer patients can benefit more from CM treatment if the theory of precision medicine is applied to CM clinical practice. So, we developed a novel diagnostic and therapeutic strategy "disease-syndrome differentiation-genomic profiling-prescriptions" for cancer patients by CM syndrome differentiation and precision medicine. As a result, this strategy has greatly enhanced the anti-tumor efficacy of CM and improved clinical outcomes for cancer patients with some gene mutations. Our idea will hopefully establish a novel approach for the inheritance and innovation of CM.

Inhibition of Liver Cancer HepG2 Cell Proliferation by Enzymatically Prepared Low-molecular Citrus Pectin.

BACKGROUND: Low-molecular citrus pectin (LCP) is a pectin polysaccharide with low molec-ular weight, low degree of crux, and no branching. It is obtained by degrading natural citrus pectin (CP) through physical, chemical and enzymatic methods. LCP has received considerable attention in recent years due to its potential applications in the medical and biological fields. METHODS: In our previous study, LCP was prepared from CP by using recombinant Bacillus subtilis pectate lyase B. Monosaccharide comparative analysis revealed that the galacturonic acid content of LCP was higher than that of CP. The cell viability effect of LCP was elucidated by using HepG2 cells and the Cell Counting Kit-8 (CCK-8) assay. Terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining, Annexin V-FITC/PI staining, and flow cytometer propidium iodide stain-ing were performed to detect the effects of LCP on apoptosis and cell cycle arrest in HepG2 cells. Mi-tochondrial membrane potential (MMP) was observed through 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethyl-imidacarbocyanine assay. RESULTS & DISCUSSION: The Mw of the prepared LCP was 7.6 kDa, which was significantly lower than that of CP (140 kDa). Cell viability decreased with the increase in the concentration of LCP. The half-inhibitory concentration of 1.46 ± 0.02 mg/mL was determined. Treatment with 1.6 mg/mL LCP in-duced the apoptosis of HepG2 cells with the inhibition rate of 83.10% ± 4.72%, and the cell cycle was arrested in the S phase. Furthermore, the MMP of HepG2 cells decreased with the increase in LCP concentration. CONCLUSION: The enzymatically prepared LCP could inhibit the proliferation of HepG2 cells. This study provided a partial experimental basis and reference for LCP to become a potential functional food for anti-liver cancer.

Evidence That ITPR2-Mediated Intracellular Calcium Release in Oligodendrocytes Regulates the Development of Carbonic Anhydrase II + Type I/II Oligodendrocytes and the Sizes of Myelin Fibers.

Myelination of neuronal axons in the central nervous system (CNS) by oligodendrocytes (OLs) enables rapid saltatory conductance and axonal integrity, which are crucial for normal brain functioning. Previous studies suggested that different subtypes of oligodendrocytes in the CNS form different types of myelin determined by the diameter of axons in the unit. However, the molecular mechanisms underlying the developmental association of different types of oligodendrocytes with different fiber sizes remain elusive. In the present study, we present the evidence that the intracellular Ca2+ release channel associated receptor (Itpr2) contributes to this developmental process. During early development, Itpr2 is selectively up-regulated in oligodendrocytes coinciding with the initiation of myelination. Functional analyses in both conventional and conditional Itpr2 mutant mice revealed that Itpr2 deficiency causes a developmental delay of OL differentiation, resulting in an increased percentage of CAII+ type I/II OLs which prefer to myelinate small-diameter axons in the CNS. The increased percentage of small caliber myelinated axons leads to an abnormal compound action potentials (CAP) in the optic nerves. Together, these findings revealed a previously unrecognized role for Itpr2-mediated calcium signaling in regulating the development of different types of oligodendrocytes.

AATYK is a Novel Regulator of Oligodendrocyte Differentiation and Myelination.

Oligodendrocytes (OLs) are myelinating glial cells that form myelin sheaths around axons to ensure rapid and focal conduction of action potentials. Here, we found that an axonal outgrowth regulatory molecule, AATYK (apoptosis-associated tyrosine kinase), was up-regulated with OL differentiation and remyelination. We therefore studied its role in OL differentiation. The results showed that AATYK knockdown inhibited OL differentiation and the expression of myelin genes in vitro. Moreover, AATYK-deficiency maintained the proliferation status of OLs but did not affect their survival. Thus, AATYK is essential for the differentiation of OLs.

Novel schizophrenia risk factor pathways regulate FEZ1 to advance oligodendroglia development.

Neuropsychiatric disorders, represented by schizophrenia, affect not only neurons but also myelinating oligodendroglia (OL), both contribute to the complex etiology. Although numerous susceptibility genes for schizophrenia have been identified, their function has been primarily studied in neurons. Whether malfunction of risk genes underlies OL defects in schizophrenia pathogenesis remains poorly understood. In this study, we investigated the function and regulation of the well-recognized schizophrenia risk factor, Fasciculation and Elongation Protein Zeta-1 (FEZ1), in OL. We found that FEZ1 is expressed in oligodendroglia progenitor cells (OPCs) derived from rodent brains and human induced pluripotent stem cells (iPSCs) in culture and in myelinating oligodendrocytes in the brain. In addition, a vigorous upregulation of FEZ1 occurs during OPC differentiation and myelinogenesis, whereas knockdown of FEZ1 significantly attenuates the development of OL process arbors. We further showed that transcription of the Fez1 gene in OL cells is governed by a sophisticated functional interplay between histone acetylation-mediated chromatin modification and transcription factors that are dysregulated in schizophrenia. At the post-transcriptional level, the selective RNA-binding protein QKI, a glia-specific risk factor of schizophrenia, binds FEZ1 mRNA. Moreover, QKI deficiency results in a marked reduction of FEZ1 specifically in OL cells of the quakingviable (qkv) hypomyelination mutant mice. These observations have uncovered novel pathways that involve multifaceted genetic lesions and/or epigenetic dysregulations in schizophrenia, which converge on FEZ1 regulation and cause OL impairment in neuropsychiatric disorders.

Tmeff2 is expressed in differentiating oligodendrocytes but dispensable for their differentiation in vivo.

Myelin elaborated by oligodendrocytes (OLs) in the central nervous system (CNS) is required for saltatory conduction of action potentials along neuronal axons. We found that TMEFF2, a transmembrane protein with EGF-like and two follistatin-like domains, is selectively expressed in differentiating/myelinating OLs. Previous studies showed that TMEFF2 is capable of binding to PDGFA, which plays important roles in the proliferation, migration and differentiation of oligodendrocyte progenitor cells (OPCs). However, molecular and genetic analysis revealed that Tmeff2 is a weak binder of PDGFA, and not required for OL differentiation and myelin gene expression in vivo. Together, our data suggested that Tmeff2 is specifically upregulated in OLs, but dispensable for OL differentiation and maturation.

TAPP1 inhibits the differentiation of oligodendrocyte precursor cells via suppressing the Mek/Erk pathway.

Oligodendrocytes (OLs) are glial cells that form myelin sheaths around axons in the central nervous system (CNS). Loss of the myelin sheath in demyelinating and neurodegenerative diseases can lead to severe impairment of movement. Understanding the extracellular signals and intracellular factors that regulate OL differentiation and myelination during development can help to develop novel strategies for enhancing myelin repair in neurological disorders. Here, we report that TAPP1 was selectively expressed in differentiating OL precursor cells (OPCs). TAPP1 knockdown promoted OL differentiation and myelin gene expression in culture. Conversely, over-expression of TAPP1 in immature OPCs suppressed their differentiation. Moreover, TAPP1 inhibition in OPCs altered the expression of Erk1/2 but not AKT. Taken together, our results identify TAPP1 as an important negative regulator of OPC differentiation through the Mek/Erk signaling pathway.