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.

Elevated expression of receptors for EGF, PDGF, transferrin and folate within murine and human lupus nephritis kidneys

OBJECTIVE

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease where the body's immune system targets cells and tissue in numerous organs, including the kidneys. Lupus nephritis (LN) is a highly heterogeneous disease, and diagnosis is difficult because clinical manifestations vary widely among patients. Comprehensive proteomic studies reported recently in LN have identified several urinary proteins which are also cell-surface receptors. If indeed these receptor proteins are also hyper-expressed within the kidneys, ligands to these receptors may be useful for drug targeting.

METHODS

scRNA sequence data analysis and immunohistochemistry were performed on LN kidneys for expression of four implicated receptors, EGFR, FOL2R2, PDGF-RB, and TFRC.

RESULTS

In reported scRNA sequencing studies from 21 LN patients and 3 healthy control renal biopsies or renal-infiltrating immune cells from 24 LN biopsies, EGFR, FOLR2, PDGF-Rb, and TFRC were all hyper expressed within LN kidneys in comparison to healthy kidneys, either within resident renal cells or infiltrating leukocytes. Immunohistochemistry staining of murine lupus renal biopsies from lupus mice revealed EGFR, FOLR2, TFRC and PDGF-RB were elevated in LN kidneys. Immunohistochemistry staining of human Class II, Class III, and Class IV kidney tissue sections revealed EGFR, TFRC, and PDGF-RB were significantly elevated in proliferative LN kidneys.

CONCLUSION

These findings underscore the potential of EGFR, TFRC, FOLR2, and PDGF-RB as promising receptors for potential drug-targeting in LN.

Tissue-resident FOLR2+ macrophages associate with CD8+ T cell infiltration in human breast cancer

Macrophage infiltration is a hallmark of solid cancers, and overall macrophage infiltration correlates with lower patient survival and resistance to therapy. Tumor-associated macrophages, however, are phenotypically and functionally heterogeneous. Specific subsets of tumor-associated macrophage might be endowed with distinct roles on cancer progression and antitumor immunity. Here, we identify a discrete population of FOLR2+ tissue-resident macrophages in healthy mammary gland and breast cancer primary tumors. FOLR2+ macrophages localize in perivascular areas in the tumor stroma, where they interact with CD8+ T cells. FOLR2+ macrophages efficiently prime effector CD8+ T cells ex vivo. The density of FOLR2+ macrophages in tumors positively correlates with better patient survival. This study highlights specific roles for tumor-associated macrophage subsets and paves the way for subset-targeted therapeutic interventions in macrophages-based cancer therapies.

Characterization of soluble folate receptors (folate binding proteins) in humans. Biological roles and clinical potentials in infection and malignancy

This review surveys soluble Folate Receptors (FOLRs) in humans. FOLR1 and FOLR2 are equipped with cellular glycosylphosphatidylinositol (GPI) anchors. FOLR1 is secreted from epithelia with or without a micelle-encapsulated GPI-anchor into milk and other body fluids/secretions, e.g. semen where its interaction with spermatozoa indicates a role in male fertility. FOLR1 and FOLR2 serve as serum biomarkers of various diseases. FOLR3 possesses no GPI-anchor and originates from secretory granules of neutrophil granulocytes; its concentration in serum correlates to the FOLR3 content in leukocytes and rises with increased leukocyte counts (infection, malignancy and pregnancy). FOLR3 exerts anti-microbial and anti-tumor effects by depriving bacteria and tumor cells of natural folates. Megalin receptors mediate reabsorption of ultrafiltered folate-bound FOLR into cells of proximal kidney tubules and of folate-bound FOLR uptake in growing embryos. Megalin receptors overexpressed in malignant tumors could be suitable therapeutic targets for folate-conjugated cytotoxic agents utilizing soluble FOLRs as vectors.

Rhesus Brain Transcriptomic Landscape in an ex vivo Model of the Interaction of Live Borrelia Burgdorferi With Frontal Cortex Tissue Explants

Lyme neuroborreliosis (LNB) is the most dangerous manifestation of Lyme disease caused by the spirochete Borrelia burgdorferi which can reach the central nervous system most commonly presenting with lymphocytic meningitis; however, the molecular basis for neuroborreliosis is still poorly understood. We incubated explants from the frontal cortex of three rhesus brains with medium alone or medium with added live Borrelia burgdorferi for 6, 12, and 24 h and isolated RNA from each group was used for RNA sequencing with further bioinformatic analysis. Transcriptomic differences between the ex vivo model of live Borrelia burgdorferi with rhesus frontal cortex tissue explants and the controls during the progression of the infection were identified. A total of 2249, 1064, and 420 genes were significantly altered, of which 80.7, 52.9, and 19.8% were upregulated and 19.3, 47.1, 80.2% were downregulated at 6, 12, and 24 h, respectively. Gene ontology and KEGG pathway analyses revealed various pathways related to immune and inflammatory responses during the spirochete infection were enriched which is suggested to have a causal role in the pathogenesis of neurological Lyme disease. Moreover, we propose that the overexpressed FOLR2 which was demonstrated by the real-time PCR and western blotting could play a key role in neuroinflammation of the neuroborreliosis based on PPI analysis for the first time. To our knowledge, this is the first study to provide comprehensive information regarding the transcriptomic signatures that occur in the frontal cortex of the brain upon exposure to Borrelia burgdorferi, and suggest that FOLR2 is a promising target that is associated with neuroinflammation and may represent a new diagnostic or therapeutic marker in LNB.

Purifying selection against gene conversions in the folate receptor genes of primates

We characterized the gene conversions between the human folate receptor (FOLR) genes and those of five other primate species. We found 26 gene conversions having an average length of 534 nucleotides. The length of these conversions is correlated with sequence similarity, converted regions have a higher GC-content and the average size of converted regions from a functional donor to another functional donor is significantly smaller than the average size from a functional donor to a pseudogene. Furthermore, the few conversions observed in the FOLR1 and FOLR2 genes did not change any amino acids in their coding regions and did not affect their promoter regions. In contrast, the promoter and coding regions of the FOLR3 gene are frequently converted and these conversions changed many amino acids in marmoset. These results suggest that purifying selection is limiting the functional impact that frequent gene conversions have on functional folate receptor genes.