Targeted overexpression of leptin to keratinocytes in transgenic mice results in lack of skin phenotype but induction of early leptin resistance.
The epidermis has a great potential as a bioreactor to produce proteins with systemic action. However, the consequences of ectopic epidermal protein overexpression need to be carefully addressed to avoid both local and systemic adverse effects. Thus, the long-term effects of leptin on skin physiology have not been studied, and the metabolic consequences of sustained keratinocyte-derived leptin overexpression are unknown. Herein we describe that very high serum leptin levels can be achieved from a cutaneous source in transgenic mice in which leptin cDNA overexpression was driven by the keratin K5 gene regulatory sequences. Histopathological analysis including the study of skin differentiation and proliferation markers in these transgenic mice revealed that keratinocyte-derived leptin overexpression appears not to have any impact on cutaneous homeostasis. Although young K5-leptin transgenic mice showed remarkable thinness and high glucose metabolism as shown in other leptin transgenic mouse models, a marked leptin insensitivity become apparent as early as 3-4 months of age as demonstrated by increased weight gain and insulin resistance development. Other signs of leptin/insulin resistance included increased bone mass, organomegaly, and wound healing impairment. In addition, to provide evidence for the lack of untoward effects of leptin on epidermis, this transgenic mouse helps us to establish the safe ranges of keratinocyte-derived leptin overexpression and may be useful as a model to study leptin resistance.
Epithelial Damage, Repair, and Tissue Engineering Unit, Centro de Investigaciones Energeticas Medioambientales y Tecnológicas, and Fundación Marcelino Botín, Avenida Complutense 22, 28040 Madrid, Spain.
Laura
L
Rico
Marcela
M
Del Rio
Ana
A
Bravo
Angel
A
Ramirez
José L
JL
Jorcano
M Angustias
MA
Page
Fernando
F
Larcher
D000273:Adipose Tissue / Q000166:cytology; D000818:Animals; D000831:Animals, Newborn; D001835:Body Weight; D002454:Cell Differentiation; D004351:Drug Resistance / Q000235:genetics; D002149:Energy Intake; D000078404:Epidermal Cells; D004817:Epidermis / Q000502:physiology; D053569:Keratin-15; D053555:Keratin-5; D015603:Keratinocytes / Q000502:physiology*; D007633:Keratins / Q000235:genetics; D020738:Leptin / Q000097:blood / Q000235:genetics*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008822:Mice, Transgenic; D012867:Skin / Q000166:cytology*; D014945:Wound Healing
D053569:Keratin-15; D053555:Keratin-5; C492053:Krt15 protein, mouse; D020738:Leptin; D007633:Keratins