Related Experiment Video

Updated: May 24, 2026

Studying Chronic Exposure of Mice to Ultraviolet B Radiation
03:20

Studying Chronic Exposure of Mice to Ultraviolet B Radiation

Published on: August 19, 2025

Differential activation of signaling pathways by UVA and UVB radiation in normal human epidermal keratinocytes

Deeba N Syed1, Farrukh Afaq, Hasan Mukhtar

  • 1Department of Dermatology, University of Wisconsin, Madison, WI, USA.

Photochemistry and Photobiology
|February 17, 2012
PubMed

Insights

Ultraviolet (UV) radiation, from UVA and UVB, impacts skin cell signaling pathways differently. Understanding these distinct effects on normal human epidermal keratinocytes (NHEK) can inform UV radiation risk assessment and targeted interventions.

Area of Science:

  • Dermatology
  • Molecular Biology
  • Photobiology

Background:

  • Solar ultraviolet (UV) radiation is a primary cause of skin diseases, including cancer.
  • Understanding UV-induced cell signaling pathways is crucial for developing prevention and treatment strategies.
  • Current research faces challenges due to inconsistent light sources and dosimetry, hindering data comparison.

Purpose of the Study:

  • To investigate the differential effects of UVA and UVB radiation on cell signaling pathways in normal human epidermal keratinocytes (NHEK).
  • To establish a foundation for understanding UV-A and UV-B specific molecular responses in human skin.
  • To provide insights for improved UV radiation risk assessment and targeted therapeutic interventions.

Main Methods:

  • Exposure of NHEK to specific doses of UVA (2 and 4 J cm(-2)) or UVB (20 and 40 mJ cm(-2)).
  • Utilized western blot analysis to assess protein phosphorylation and expression levels.
  • Examined the activation and nuclear translocation of key signaling proteins.

Main Results:

  • UVB uniquely phosphorylated JNK1/2, STAT3 (Ser727), AKT (Ser473), and increased c-Fos.
  • UVA uniquely phosphorylated AKT (Thr308).
  • Both UVA and UVB induced phosphorylation of ERK1/2, p38, STAT3 (Tyr705), mTOR, and p70S6k; increased PI3K (p85) and c-jun expression; and caused NFκB nuclear translocation.

Conclusions:

  • UVA and UVB radiation elicit distinct and overlapping signaling responses in human epidermal keratinocytes.
  • These findings highlight the differential molecular impacts of UVA and UVB, crucial for understanding UV-related skin pathologies.
  • The study provides a basis for developing targeted interventions against specific UV-induced signaling events.

More Related Videos

Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model12:37

Pharmacologic Induction of Epidermal Melanin and Protection Against Sunburn in a Humanized Mouse Model

Published on: September 7, 2013

Isolation and Culture of Primary Mouse Keratinocytes from Neonatal and Adult Mouse Skin10:51

Isolation and Culture of Primary Mouse Keratinocytes from Neonatal and Adult Mouse Skin

Published on: July 14, 2017

Related Concept Videos

Mutations01:35

Mutations

Mutations are changes in the sequence of DNA. These changes can occur spontaneously or they can be induced by exposure to environmental factors. Mutations can be characterized in a number of different ways: whether and how they alter the amino acid sequence of the protein, whether they occur over a small or large area of DNA, and whether they occur in somatic cells or germline cells.
Chromosomal Alterations Are Large-Scale Mutations
While point mutations are changes in a single nucleotide in...
Nucleotide Excision Repair01:38

Nucleotide Excision Repair

DNA Distortion and Damage
Cells are regularly exposed to mutagens—factors in the environment that can damage DNA and generate mutations. UV radiation is one of the most common mutagens and is estimated to introduce a significant number of changes in DNA. These include bends or kinks in the structure, which can block DNA replication or transcription. If these errors are not fixed, the damage can cause mutations, which in turn can result in cancer or disease depending on which sequences are...
Nucleotide Excision Repair01:08

Nucleotide Excision Repair

Overview
Pigmentation01:19

Pigmentation

The color of the skin is influenced by a number of pigments, including melanin, carotene, and hemoglobin. Recall that melanin is produced by cells called melanocytes, which are found scattered throughout the stratum basale of the epidermis. The melanin is transferred to the keratinocytes via melanosomes.
Melanin occurs in two primary forms: eumelanin that provides black and brown pigment and pheomelanin that provides red color. Dark-skinned individuals produce more melanin than those with pale...
Skin Cancer01:30

Skin Cancer

Skin cancer is a type of cancer that occurs when there is an abnormal growth of skin cells, usually triggered by damage to the DNA within the skin cells. It is primarily caused by exposure to ultraviolet (UV) radiation from the sun or artificial sources like tanning beds. Skin cancer is the most common type of cancer worldwide, and its incidence continues to rise.
Basal Cell Carcinoma (BCC): BCC is the most common type of skin cancer, accounting for about 80% of cases. It typically develops in...
Renewal of Skin Epidermal Stem Cells01:12

Renewal of Skin Epidermal Stem Cells

The skin is divided into epidermis, dermis, and hypodermis, the skin's outermost, middle, and inner layers. The human epidermal layer regularly undergoes renewal, where old, dead cells are replaced by new cells. Epidermal stem cells or EpiSCs divide and differentiate to restore the lost cells. For the renewal process, some EpiSCs continuously self-renew. In contrast, few others differentiate into transit-amplifying cells, which later form prickle or spinous cells, followed by granular cells,...