Milk miRNAs: simple nutrients or systemic functional regulators?

Area of Science:

• Biochemistry
• Developmental Biology
• Genetics

Background:

• Milk contains microRNAs (miRNAs) implicated in mammalian postnatal development.
• Two hypotheses exist: functional (miRNAs transfer and regulate) and nutritional (miRNAs are non-functional nutrients).
• The functional hypothesis requires more robust evidence.

Purpose of the Study:

• To evaluate the suitability of existing mouse models for studying milk miRNA function.
• To highlight potential limitations in current research paradigms.
• To advocate for new research approaches using more appropriate models or human milk.

Main Methods:

• Critical review of existing literature and mouse models.
• Analysis of indirect evidence supporting the functional hypothesis.
• Identification of potential flaws in miRNA-375 KO, miRNA-200c/141 KO, and transgenic miRNA-30b mouse models.

Main Results:

• Circumstantial evidence suggests current mouse models may be inappropriate for studying milk miRNA physiological traffic.
• Existing models might not accurately reflect miRNA behavior in newborns or adult consumers.
• The validity of the nutritional hypothesis, based on these models, is questioned.

Conclusions:

• Current mouse models used to study milk miRNAs are potentially flawed.
• Further investigation using more relevant models or human milk is essential.
• The true physiological role and fate of milk miRNAs in mammals remain to be fully elucidated.