Related Experiment Videos
Sensitivity of HaCat keratinocytes to diabetogenic toxins
Avikam Harel1, Olga Bloch, Pnina Vardi
1The Pediatric Dermatology Unit and The Gino Stock Dermatophysiology Laboratory, Dana Children's Hospital, Tel Aviv Sourasky Medical Center, 64239, Tel Aviv, Israel. dermped@tasmc.health.gov.il
Abstract:
Metabolic, genetic and environmental factors very likely play an important role in the development of skin lesions in diabetes mellitus. While these lesions are involved in secondary diabetes complications, various diabetogenic genotoxic agents may induce direct skin damage. In the present study we examined the potential of known diabetogenic agents (streptozotocin (STZ) and alloxan (AL)), with different mechanisms of action, for induction of direct injury in an immortal human keratinocyte HaCat cell line. In contrast to STZ, which induces alkylation of DNA, a genotoxic effect of AL is achieved through reactive oxygen species. We found that HaCat cells are highly sensitive to STZ, but not to AL. At a concentration of 10mM STZ, cell viability decreased to 32 +/-13% of control (P<0.05), as compared to 82 +/-14% with 10mM of AL. Cells treated with 10 and 20mM STZ showed a significant increase in apoptosis (3.9- and 6.7-fold), but not in necrosis, compared to naive cells (P<0.05). In contrast to STZ, no increase in apoptotic and necrotic cell death was observed after AL treatment. Pretreatment with non-metabolizable 3-O-methyl glucose (3-OMG), which can blockade glucose transporter, or with poly(ADP-ribose) polymerase inhibitors (nicotinamide or 3-aminobenzamide), did not protect keratinocytes from STZ injury. Our results show that STZ, but not AL, is highly toxic to the HaCat cell line. Unlike insulin-producing cells, STZ-induced injury of immortal human keratinocyte HaCat cells is independent of the glucose transporters as well as of the activation of poly(ADP-ribose) polymerase.
Insights
Streptozotocin (STZ) is highly toxic to human keratinocytes, inducing apoptosis, unlike alloxan (AL). This STZ-induced skin cell damage is independent of glucose transporters and poly(ADP-ribose) polymerase.
Area of Science:
- Dermatology
- Toxicology
- Cell Biology
Background:
- Diabetes mellitus complications can include skin lesions.
- Diabetogenic agents may directly damage skin cells.
- Investigating direct injury from diabetogenic agents in keratinocytes is crucial.
Purpose of the Study:
- To compare the direct cytotoxic effects of streptozotocin (STZ) and alloxan (AL) on immortal human keratinocytes (HaCaT cells).
- To elucidate the mechanisms of STZ-induced keratinocyte injury.
Main Methods:
- Exposure of HaCaT cells to varying concentrations of STZ and AL.
- Assessment of cell viability, apoptosis, and necrosis.
- Evaluation of protective effects of glucose transporter blockade and poly(ADP-ribose) polymerase inhibitors.
Main Results:
- HaCaT cells demonstrated high sensitivity to STZ, with significant decreases in viability and increased apoptosis.
- AL showed minimal toxicity to HaCaT cells at comparable concentrations.
- STZ-induced keratinocyte injury was not prevented by blocking glucose transporters or inhibiting poly(ADP-ribose) polymerase.
Conclusions:
- STZ is a potent inducer of direct injury and apoptosis in immortal human keratinocytes.
- The mechanism of STZ toxicity in keratinocytes differs from that in insulin-producing cells, being independent of glucose transporters and poly(ADP-ribose) polymerase.