Mechanism analysis of long-term graft survival by monocarboxylate transporter-1 inhibition

Area of Science:

• Immunology
• Transplantation Biology
• Pharmacology

Background:

• Monocarboxylate transporter (MCT)-1 facilitates lactate transport.
• Inhibition of MCT-1 has shown potential for promoting long-term graft survival and inducing tolerance in transplantation models.
• AS2495674 is an MCT-1 inhibitor evaluated for its efficacy and mechanism in a rat heart transplant model.

Purpose of the Study:

• To evaluate the efficacy of the MCT-1 inhibitor AS2495674 in a rat heart transplant model.
• To analyze the underlying immunological mechanisms by which AS2495674 influences graft survival and tolerance.

Main Methods:

• In vitro testing of AS2495674 on rat lymphocytes for effects on lactate accumulation, proliferation, and immunoglobulin production.
• In vivo testing in a Brown Norway to Lewis rat heart transplant model, including a second transplantation to assess donor-specific suppression.
• Histological and ex vivo analyses of allografts and peripheral T lymphocytes to examine immune response modulation.

Main Results:

• AS2495674 treatment in vitro led to lactate accumulation, inhibited lymphocyte proliferation, and reduced immunoglobulin production.
• AS2495674 significantly improved long-term allograft survival with minimal chronic rejection and induced donor-specific suppression.
• Analysis revealed decreased donor-specific T lymphocyte response, increased Foxp3+ and CD45RA+ cells, elevated chemokine gene expression, and preferential inhibition of Foxp3(-) cells.

Conclusions:

• AS2495674 effectively prevents acute rejection, mitigates chronic rejection features, and induces transplant tolerance.
• The mechanism involves creating a tolerogenic graft environment by selectively inhibiting T effector cells while sparing T regulatory cells.