Effective Delivery of Endogenous Antioxidants Ameliorates Diabetic Nephropathy.

Background: Diabetic nephropathy (DN) is thought to be partially due to the injury of renal cells and the renal micro-environment by free radicals. Free radial scavenging agents that inhibit free radical damage may well prevent the development of underlying conditions such as mesangial expansion (by inhibiting extracellular matrix expression) in these patients.

Methods: Using techniques for intra-cellular delivery of peptides, we made metallothionein (MT) and superoxide dismutase (SOD), potent endogenous antioxidants, readily transducible into cell membrane and tested their protective effect against the development of DN in OLETF rats.

Amelioration of diabetic neuropathy by TAT-mediated enhanced delivery of metallothionein and SOD.

Because diabetic neuropathy (DN) appears to result from oxidative stress in neuronal tissues, antioxidant treatment should counteract the condition. Metallothionein (MT) and superoxide dismutase (SOD) are free-radical scavengers, but their ability to cross biological membranes is limited. Applying cell penetrating peptide technologies, we made Tat-MT and Tat-SOD constructs and tested their ability to protect PC12 cells, as surrogates of peripheral nerve cells, from various forms of oxidative damage.

Evidence for the role of STAT4 as a general autoimmunity locus in the Korean population.

Background: Recently, the association of a common STAT4 haplotype with type 1 diabetes (T1D) as well as rheumatoid arthritis has been documented in Caucasians and Koreans. STAT4 is involved in the signalling of interleukin-12 and γIFN, as well as interleukin-23. To discover genes affecting the susceptibility of common autoimmune diseases, we studied the association of polymorphisms in STAT4 with autoimmune thyroid disease (AITD) as well as T1D in the Korean population.

The combination of metallothionein and superoxide dismutase protects pancreatic β cells from oxidative damage.

Background: Reactive oxygen species are considered an important cause of the death of pancreatic β cells, thereby triggering the development of type 2 diabetes as well as failure of islet transplantation. The biological properties of metallothionein (MT) and superoxide dismutase (SOD) are likely to be related to their antioxidant and free-radical scavenging abilities, but their access across biological membranes is limited.

Methods: We investigated whether Tat-MT and Tat-SOD fusion protein could be introduced into islets by a novel protein transduction technology and protect them from oxidative damage.

Tat-enhanced delivery of metallothionein can partially prevent the development of diabetes.

Metallothioneins (MTs) are intracellular low-molecular-weight, cysteine-rich proteins with potent metal-binding and redox functions, but with limited membrane permeativity. The aim of this study was to investigate whether we could enhance delivery of MT-1 to pancreatic islets or β cells in vitro and in vivo. The second goal was to determine whether increased MT-1 could prevent cellular toxicity induced by high glucose and free fatty acids in vitro (glucolipotoxicity) and ameliorate the development of diabetes induced by streptozotocin in mice or delay the development of diabetes by improving insulin secretion and resistance in the OLETF rat model of type 2 diabetes.