Using real-time PCR to identify pregnancy-associated glycoprotein 2 (PAG-2) in water buffalo (Bubalus bubalis) blood in early pregnancy

his study investigates for the first time mRNA pregnancy-associated glycoprotein 2 (PAG-2) expression in blood cells during early pregnancy in water buffalo. The PAGs constitute a large family of glycoproteins expressed in the outer epithelial layer of the placenta in eutherian species. All PAGs are not concomitantly expressed throughout pregnancy; some of them are expressed in the earlier phases, whereas others appear later and are expressed over a shorter period. Twenty-one lactating buffaloes were analyzed-17 females were synchronized with PRID and artificially inseminated (AI), whereas four females were synchronized but not inseminated (control group). Blood was collected at Days 0, 18, 28, 40, and 75 from AI (AI = Day 0). Expression of PAG-2 mRNA in blood samples was measured with real-time polymerase chain reaction. Pregnancy diagnosis was performed on Day 28 (D28) and Day 40 (D40) after AI by ultrasonography (US) and by PAG-1 RIA method. The females diagnosed pregnant at D28 and confirmed pregnant at D40 were defined as D28(+)D40(+) group; the females diagnosed pregnant at D28 but not confirmed pregnant at D40 were defined as D28(+)D40(-) group; and the females that were diagnosed as nonpregnant on either days were defined as D28(-)D40(-) group. PAG-2 mRNA at Day 0 was not observed in any groups. The D28(+)D40(+) group showed the highest expression, starting on Day 18 and increasing progressively up to Day 75. PAG-2 mRNA was also expressed on Day 18 in both D28(+)D40(-) and D28(-)D40(-) groups, but their levels were lower than those of D28(+)D40(+) group and almost constant over time. PAG-2 mRNA was never detected in the control group. The significant difference in the expression of PAG-2 mRNA between the D28(+)D40(+) group and the D28(-)D40(-) group, starting from Day 18, suggests that these animals might have conceived, but have experienced early embryonic loss; therefore, the PAG-2 mRNA was still present in blood circulation although at lower levels, as found in the D28(+)D40(-) group. In conclusion, this study shows that PAG-2 mRNA can be detected in peripheral maternal blood cells earlier than circulating PAG-1 molecules and could be useful for studies on early pregnancy and embryonic mortality

Tight junction protein claudin-2 promotes self-renewal of human colorectal cancer stem-like cells

Posttreatment recurrence of colorectal cancer, the third most lethal cancer worldwide, is often driven by a subpopulation of cancer stem cells (CSC). The tight junction (TJ) protein claudin-2 is overexpressed in human colorectal cancer, where it enhances cell proliferation, colony formation, and chemoresistance in vitro. While several of these biological processes are features of the CSC phenotype, a role for claudin-2 in the regulation of these has not been identified. Here, we report that elevated claudin-2 expression in stage II/III colorectal tumors is associated with poor recurrence free survival following 5-fluorouracil–based chemotherapy, an outcome in which CSCs play an instrumental role. In patient-derived organoids, primary cells, and cell lines, claudin-2 promoted colorectal cancer self-renewal in vitro and in multiple mouse xenograft models. Claudin-2 enhanced self-renewal of ALDH High CSCs and increased their proportion in colorectal cancer cell populations, limiting their differentiation and promoting the phenotypic transition of non-CSCs toward the ALDH High phenotype. Next-generation sequencing in ALDH High cells revealed that claudin-2 regulated expression of nine miRNAs known to control stem cell signaling. Among these, miR-222-3p was instrumental for the regulation of self-renewal by claudin-2, and enhancement of this self-renewal required activation of YAP, most likely upstream from miR-222-3p. Taken together, our results indicate that overexpression of claudin-2 promotes self-renewal within colorectal cancer stem-like cells, suggesting a potential role for this protein as a therapeutic target in colorectal cancer. Significance: Claudin-2-mediated regulation of YAP activity and miR-222-3p expression drives CSC renewal in colorectal cancer, making it a potential target for therapy.Sophie Paquet-Fifield ... Melissa J. Davis ... et. a