Regulation of miRNAs as new tool for cutaneous vitality lesions demonstration in ligature marks in deaths by hanging

Margherita Neri,Matteo Fabbri,Emanuela Turillazzi,Stefano D’Errico,Matteo Marti,Paola Frati,Aniello Maiese,Enrica Pinchi,Raffaele La Russa,Marco Di Paolo,Rosa Maria Gaudio,Vittorio Fineschi

doi:10.1038/s41598-019-56682-7

Abstract

This study aims to demonstrate that the application of miRNA expression in forensic pathology, in cases of hanging, applying the method on skin samples. The proposed investigative protocol allowed us to highlight a different miRNA expression in the skin ligature marks of subjects who died by hanging compared to healthy skin control samples. The results obtained showed an increase in the expression of miRNAs recognized as regulators of the inflammatory response in skin lesions such as miR125a-5p and miR125b-5p. Furthermore, overexpression of additional miRNAs – miR214a-3p, miR128-3p, miR130a-3p, and miR92a-3p – with anti-inflammatory activity was highlighted. It was possible to document a statistical significance to control skin samples only for miR103a-3p (p < 0.05), miR214-3p and miR92a-3p (p < 0.01) The upregulation of miR222-3p and miR150-5p, respectively related to mast-cell activation and neutrophils after the application of traumatic stimuli supports the immunohistochemical data showed in literature. The diagnostic accuracy of miRNAs could expand the range of diagnostic tools available in the assessment of the vitality of a lesion.

Highlights

This study aims to demonstrate that the application of miRNA expression in forensic pathology, in cases of hanging, applying the method on skin samples
The graph is characterized by the presence of a straight black line corresponding to the average of the miRNA values obtained from the control skin samples, first normalized and expressed as a logarithmic function on the abscissa axis, while the microRNA values of the ligature marked skin are shown on the ordinate axis
Overexpression of additional miRNAs – miR214a-3p, miR128-3p, miR130a-3p, miR122-5p and miR92a-3p – with anti-inflammatory activity was highlighted; it was possible to document a statistical significance compared with control skin samples only for miR214a-3p, miR130a-3p and miR92a-3p

Summary

Introduction

This study aims to demonstrate that the application of miRNA expression in forensic pathology, in cases of hanging, applying the method on skin samples. Wound age evaluation is one of the hardest challenges for the forensic pathologist when asked to establish the vitality of a skin lesion since, especially at the very beginning of the healing process, traditional histological and immunohistochemical examinations may not provide solid objective evidence[13]. Since miRNAs play a pivotal role in regulating the expression of key proteins that control the complex inflammatory response[16,17,18,19] and since, after wounding, the mRNA levels of cytokines and enzymes typically change sooner than protein levels and the histomorphology[20,21,22,23], we proceeded to investigate whether the expression of some selected miRNAs was modified in ligature marks (patterned abrasion caused by ligature material) in death by hanging. We acknowledged that gross and histological examination of these marks may sometimes be unreliable and may mislead the forensic pathologist into concluding as to whether they are due to hanging or post-mortem suspension of the body[24]

Objectives

Methods

Results

Discussion

Conclusion