Deciphering the spatial landscape and plasticity of immunosuppressive fibroblasts in breast cancer.

Although heterogeneity of FAP+ Cancer-Associated Fibroblasts (CAF) has been described in breast cancer, their plasticity and spatial distribution remain poorly understood. Here, we analyze trajectory inference, deconvolute spatial transcriptomics at single-cell level and perform functional assays to generate a high-resolution integrated map of breast cancer (BC), with a focus on inflammatory and myofibroblastic (iCAF/myCAF) FAP+ CAF clusters. We identify 10 spatially-organized FAP+ CAF-related cellular niches, called EcoCellTypes, which are differentially localized within tumors. Consistent with their spatial organization, cancer cells drive the transition of detoxification-associated iCAF (Detox-iCAF) towards immunosuppressive extracellular matrix (ECM)-producing myCAF (ECM-myCAF) via a DPP4- and YAP-dependent mechanism. In turn, ECM-myCAF polarize TREM2+ macrophages, regulatory NK and T cells to induce immunosuppressive EcoCellTypes, while Detox-iCAF are associated with FOLR2+ macrophages in an immuno-protective EcoCellType. FAP+ CAF subpopulations accumulate differently according to the invasive BC status and predict invasive recurrence of ductal carcinoma in situ (DCIS), which could help in identifying low-risk DCIS patients eligible for therapeutic de-escalation.

Tumor-specific activation of folate receptor beta enables reprogramming of immune cells in the tumor microenvironment.

Folate receptors can perform folate transport, cell adhesion, and/or transcription factor functions. The beta isoform of the folate receptor (FRß) has attracted considerable attention as a biomarker for immunosuppressive macrophages and myeloid-derived suppressor cells, however, its role in immunosuppression remains uncharacterized. We demonstrate here that FRß cannot bind folate on healthy tissue macrophages, but does bind folate after macrophage incubation in anti-inflammatory cytokines or cancer cell-conditioned media. We further show that FRß becomes functionally active following macrophage infiltration into solid tumors, and we exploit this tumor-induced activation to target a toll-like receptor 7 agonist specifically to immunosuppressive myeloid cells in solid tumors without altering myeloid cells in healthy tissues. We then use single-cell RNA-seq to characterize the changes in gene expression induced by the targeted repolarization of tumor-associated macrophages and finally show that their repolarization not only changes their own phenotype, but also induces a proinflammatory shift in all other immune cells of the same tumor mass, leading to potent suppression of tumor growth. Because this selective reprogramming of tumor myeloid cells is accompanied by no systemic toxicity, we propose that it should constitute a safe method to reprogram the tumor microenvironment.

A multiomics analysis-assisted deep learning model identifies a macrophage-oriented module as a potential therapeutic target in colorectal cancer.

Colorectal cancer (CRC) is a common malignancy involving multiple cellular components. The CRC tumor microenvironment (TME) has been characterized well at single-cell resolution. However, a spatial interaction map of the CRC TME is still elusive. Here, we integrate multiomics analyses and establish a spatial interaction map to improve the prognosis, prediction, and therapeutic development for CRC. We construct a CRC immune module (CCIM) that comprises FOLR2+ macrophages, exhausted CD8+ T cells, tolerant CD8+ T cells, exhausted CD4+ T cells, and regulatory T cells. Multiplex immunohistochemistry is performed to depict the CCIM. Based on this, we utilize advanced deep learning technology to establish a spatial interaction map and predict chemotherapy response. CCIM-Net is constructed, which demonstrates good predictive performance for chemotherapy response in both the training and testing cohorts. Lastly, targeting FOLR2+ macrophage therapeutics is used to disrupt the immunosuppressive CCIM and enhance the chemotherapy response in vivo.

CD163-Mediated Small-Vessel Injury in Alzheimer's Disease: An Exploration from Neuroimaging to Transcriptomics.

Patients with Alzheimer's disease (AD) often present with imaging features indicative of small-vessel injury, among which, white-matter hyperintensities (WMHs) are the most prevalent. However, the underlying mechanism of the association between AD and small-vessel injury is still obscure. The aim of this study is to investigate the mechanism of small-vessel injury in AD. Differential gene expression analyses were conducted to identify the genes related to WMHs separately in mild cognitive impairment (MCI) and cognitively normal (CN) subjects from the ADNI database. The WMH-related genes identified in patients with MCI were considered to be associated with small-vessel injury in early AD. Functional enrichment analyses and a protein-protein interaction (PPI) network were performed to explore the pathway and hub genes related to the mechanism of small-vessel injury in MCI. Subsequently, the Boruta algorithm and support vector machine recursive feature elimination (SVM-RFE) algorithm were performed to identify feature-selection genes. Finally, the mechanism of small-vessel injury was analyzed in MCI from the immunological perspectives; the relationship of feature-selection genes with various immune cells and neuroimaging indices were also explored. Furthermore, 5×FAD mice were used to demonstrate the genes related to small-vessel injury. The results of the logistic regression analyses suggested that WMHs significantly contributed to MCI, the early stage of AD. A total of 276 genes were determined as WMH-related genes in patients with MCI, while 203 WMH-related genes were obtained in CN patients. Among them, only 15 genes overlapped and were thus identified as the crosstalk genes. By employing the Boruta and SVM-RFE algorithms, CD163, ALDH3B1, MIR22HG, DTX2, FOLR2, ALDH2, and ZNF23 were recognized as the feature-selection genes linked to small-vessel injury in MCI. After considering the results from the PPI network, CD163 was finally determined as the critical WMH-related gene in MCI. The expression of CD163 was correlated with fractional anisotropy (FA) values in regions that are vulnerable to small-vessel injury in AD. The immunostaining and RT-qPCR results from the verifying experiments demonstrated that the indicators of small-vessel injury presented in the cortical tissue of 5×FAD mice and related to the upregulation of CD163 expression. CD163 may be the most pivotal candidates related to small-vessel injury in early AD.

microRNA-622 upregulates cell cycle process by targeting FOLR2 to promote CRC proliferation.

BACKGROUND: Epigenetic alterations contribute greatly to the development and progression of colorectal cancer, and effect of aberrant miR-622 expression is still controversial. This study aimed to discover miR-622 regulation in CRC proliferation. METHODS: miR-622 expression and prognosis were analyzed in clinical CRC samples from Nanfang Hospital. miR-622 regulation on cell cycle and tumor proliferation was discovered, and FOLR2 was screened as functional target of miR-622 using bioinformatics analysis, which was validated via dual luciferase assay and gain-of-function and loss-of-function experiments both in vitro and in vivo. RESULTS: miR-622 overexpression in CRC indicated unfavorable prognosis and it regulated cell cycle to promote tumor growth both in vitro and in vivo. FOLR2 is a specific, functional target of miR-622, which negatively correlates with signature genes in cell cycle process to promote CRC proliferation. CONCLUSIONS: miR-622 upregulates cell cycle process by targeting FOLR2 to promote CRC proliferation, proposing a novel mechanism and treatment target in CRC epigenetic regulation of miR-622.

Folate receptor overexpression induces toxicity in a diet-dependent manner in C. elegans.

Folate receptor (FR) alpha (FOLR1) and beta (FOLR2) are membrane-anchored folate transporters that are expressed at low levels in normal tissues, while their expression is strongly increased in several cancers. Intriguingly, although the function of these receptors in, for example, development and cancer has been studied intensively, their role in aging is still unknown. To address this, we utilized Caenorhabditis elegans, in which FOLR-1 is the sole ortholog of folate receptors. We found that the loss of FOLR-1 does not affect reproduction, physical condition, proteostasis or lifespan, indicating that it is not required for folate transport to maintain health. Interestingly, we found that FOLR-1 is detectably expressed only in uterine-vulval cells, and that the histone-binding protein LIN-53 inhibits its expression in other tissues. Furthermore, whereas knockdown of lin-53 is known to shorten lifespan, we found that the loss of FOLR-1 partially rescues this phenotype, suggesting that elevated folr-1 expression is detrimental for health. Indeed, our data demonstrate that overexpression of folr-1 is toxic, and that this phenotype is dependent on diet. Altogether, this work could serve as a basis for further studies to elucidate the organismal effects of abnormal FR expression in diseases such as cancer.

Presence of onco-fetal neighborhoods in hepatocellular carcinoma is associated with relapse and response to immunotherapy.

Onco-fetal reprogramming of the tumor ecosystem induces fetal developmental signatures in the tumor microenvironment, leading to immunosuppressive features. Here, we employed single-cell RNA sequencing, spatial transcriptomics and bulk RNA sequencing to delineate specific cell subsets involved in hepatocellular carcinoma (HCC) relapse and response to immunotherapy. We identified POSTN+ extracellular matrix cancer-associated fibroblasts (EM CAFs) as a prominent onco-fetal interacting hub, promoting tumor progression. Cell-cell communication and spatial transcriptomics analysis revealed crosstalk and co-localization of onco-fetal cells, including POSTN+ CAFs, FOLR2+ macrophages and PLVAP+ endothelial cells. Further analyses suggest an association between onco-fetal reprogramming and epithelial-mesenchymal transition (EMT), tumor cell proliferation and recruitment of Treg cells, ultimately influencing early relapse and response to immunotherapy. In summary, our study identifies POSTN+ CAFs as part of the HCC onco-fetal niche and highlights its potential influence in EMT, relapse and immunotherapy response, paving the way for the use of onco-fetal signatures for therapeutic stratification.

WNT-dependent interaction between inflammatory fibroblasts and FOLR2+ macrophages promotes fibrosis in chronic kidney disease.

Chronic kidney disease (CKD) is a public health problem driven by myofibroblast accumulation, leading to interstitial fibrosis. Heterogeneity is a recently recognized characteristic in kidney fibroblasts in CKD, but the role of different populations is still unclear. Here, we characterize a proinflammatory fibroblast population (named CXCL-iFibro), which corresponds to an early state of myofibroblast differentiation in CKD. We demonstrate that CXCL-iFibro co-localize with macrophages in the kidney and participate in their attraction, accumulation, and switch into FOLR2+ macrophages from early CKD stages on. In vitro, macrophages promote the switch of CXCL-iFibro into ECM-secreting myofibroblasts through a WNT/ß-catenin-dependent pathway, thereby suggesting a reciprocal crosstalk between these populations of fibroblasts and macrophages. Finally, the detection of CXCL-iFibro at early stages of CKD is predictive of poor patient prognosis, which shows that the CXCL-iFibro population is an early player in CKD progression and demonstrates the clinical relevance of our findings.

Association of periconceptional folate supplements and FOLR1 and FOLR2 gene polymorphisms with risk of congenital heart disease in offspring: A hospital-based case-control study / 中南大学学报(医学版)

OBJECTIVES@#Maternal periconceptional folic acid supplement is by far the most effective primary prevention strategy to reduce the incidence of congenital heart disease (CHD) in offspring. It was revealed that the underlying mechanisms are complex, including a combination of genetic and environmental factors. The purpose of this study is to investigate the association between periconceptional folic acid supplement, the genetic polymorphisms of maternal folic acid receptor 1 gene (FOLR1) and folic acid receptor 2 gene (FOLR2) and the impact of their interaction on the risk of CHD in offspring, and to provide epidemiological evidence for individualized folic acid dosing in hygienic counseling.@*METHODS@#A case-control study on 569 mothers of CHD infants and 652 mothers of health controls was performed. The interesting points were periconceptional folate supplements, single nucleotide polymorphisms (SNPs) of maternal FOLR1 gene and FOLR2 gene.@*RESULTS@#Mothers who took folate in the periconceptional period were observed a decreased risk of CHD [adjusted odds ratio (aOR)=0.58, 95% CI 0.35 to 0.95]. Our study also found that polymorphisms of maternal FOLR1 gene at rs2071010 (G/A vs G/G: aOR=0.67, 95% CI 0.47 to 0.96) and FOLR2 gene at rs514933 (T/C vs T/T: aOR=0.60, 95% CI 0.43 to 0.84; C/C vs T/T: aOR=0.55, 95% CI 0.33 to 0.90; the dominant model: T/C+ C/C vs T/T: aOR=0.59, 95% CI 0.43 to 0.81; and the addictive model: C/C vs T/C vs T/T: aOR=0.70, 95% CI 0.56 to 0.88) were significantly associated with lower risk of CHD [all P<0.05, false discovery rate P value (FDR_P)<0.1]. Besides, significant interaction between periconceptional folate supplements and rs2071010 G→A (aOR=0.59, 95% CI 0.41-0.86) and rs514933 T→C (aOR=0.52, 95% CI 0.37 to 0.74) on CHD risk were observed (all P<0.05, FDR_P<0.1).@*CONCLUSIONS@#Periconceptional folate supplements, polymorphisms of FOLR1 gene and FOLR2 gene and their interactions are significantly associated with risk of CHD. However, more studies in different ethnic populations with a larger sample and prospective designs are required to confirm our findings.

Establishment and evaluation of enzyme-linked immunosorbent assay for measuring human IgM autoantibody to folate receptor / 中国医学科学院学报

<p><b>OBJECTIVE</b>To establish the method of enzyme-linked immunosorbent assay (ELISA) for measuring human IgM autoantibody to folate receptor.</p><p><b>METHODS</b>Folate receptor was extracted and purified from the healthy woman placenta. The protein was coated on 96-well plates with a concentration of 5 ng/Μl. Goat monoclonal antibody was used for detecting antibody. Pooled plasma from healthy donors was used to plot the standard curve and the IgM concentration of pooled plasma was defined as 1. We set up an ELISA procedure to measure human IgM autoantibody to folate receptor. The sensitivity, precision, and stability of the method were evaluated. Further, the folate receptor and bovine folate-binding protein were used as the antigen, respectively, to determine the autoantibody levels in 24 healthy individuals and 20 individuals once gave birth to baby with neural tube defects.</p><p><b>RESULTS</b>The measuring range of the method was from 6.25 × 10⁻⁴ to 8.00 × 10⁻². The lowest IgM level that can be detected was 3.12 × 10⁻⁴. The inter-assay coefficients of variations for samples with high, medium, and low IgM levels were 6.61%,3.50%, and 5.12%, respectively. The intra-assay coefficients of variations were 4.54%, 5.49%, and 5.44%, respectively. The stability test results were considered within acceptable limits. The data from folate receptor-ELISA was significantly higher than that from bovine folate binding protein-ELISA, both in the healthy group (t=-11.9, P<0.001) and in the neural tube defect group (t = 7.35, P<0.001).</p><p><b>CONCLUSIONS</b>The folate receptor-ELISA method for measuring human IgM autoantibody to folate receptor was successfully established. The method is sensitive, repeatable, and stable.</p>