Characterization of mRNA Signature in Milk Small Extracellular Vesicles from Cattle Infected with Bovine Leukemia Virus

Abstract

This study aimed to characterize the mRNA signature of milk small extracellular vesicles (sEVs) from BLV-infected cattle. A total of 23 mRNAs, which showed greater abundance in milk sEVs from BLV-infected cattle compared to those from BLV-uninfected (control) cattle, were identified through microarray analyses conducted in our previous study. To assess the significance of these differences in mRNA abundance, milk was collected from six control cattle and twenty-six cattle infected with BLV. The infected cattle were categorized into two distinct groups based on their proviral loads: a group of eight cattle with low proviral loads (LPVL), characterized by <10,000 copies per 105 white blood cells (WBC), and a group of eighteen cattle with high proviral loads (HPVL), marked by ≥10,000 copies per 105 WBC. The qPCR analysis quantified 7 out of 23 mRNAs, including BoLA, CALB1, IL33, ITGB2, MYOF, TGFBR1, and TMEM156, in the milk sEVs from control cattle, LPVL cattle, and HPVL cattle. Significantly, the average relative expression of CALB1 mRNA in milk sEVs was higher in LPVL cattle compared to HPVL cattle and control cattle (p < 0.05), while it was relatively lower in HPVL cattle compared to LPVL cattle and control cattle (p > 0.05). Likewise, the average relative expression of TMEM156 mRNA in milk sEVs was significantly higher in LPVL cattle compared to HPVL cattle (p < 0.05), and relatively lower in HPVL cattle compared to LPVL cattle and control cattle (p > 0.05). The results indicate distinct patterns of CALB1 and TMEM156 mRNA levels in milk sEVs, with higher levels observed in LPVL cattle and lower levels in HPVL cattle. The current study could provide essential information to comprehend the complexities during the progression of BLV infection and direct the exploration of mRNA biomarkers for monitoring the clinical stage of BLV infection.

Milk-Derived Extracellular Vesicles: Biomedical Applications, Current Challenges, and Future Perspectives

“…Matiur Rahman et al in a more recent study, assessed the expression of mRNAs in miEVs from BLV-infected cattle (with high or low proviral load) and uninfected cattle. 155 They found that compared to cattle with a high proviral load of BLV infection, there was a higher expression of CALB1 and TMEM156 in miEVs from cattle with a low proviral load of BLV infection. This finding further supports previous studies that showed the mRNA profile of miEVs can provide a promising resource to reflect the progression of BLV infection.…”

“…Their study revealed that eight mRNAs ( TMEM156 , SRGN , CXCL8 , DEFB4A , FABP5 , LAPTM5 , LGALS1 , and VIM ) may be potential EBL biomarkers because their expression was remarkably higher in miEVs from infected cattle. Matiur Rahman et al in a more recent study, assessed the expression of mRNAs in miEVs from BLV-infected cattle (with high or low proviral load) and uninfected cattle . They found that compared to cattle with a high proviral load of BLV infection, there was a higher expression of CALB1 and TMEM156 in miEVs from cattle with a low proviral load of BLV infection.…”