Selective HDAC6 Inhibition in Systemic Lupus Erythematosus

Miranda Diane Vieson

Dissertation submitted to the faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of

Doctor of Philosophy In Biomedical and Veterinary Sciences

Xin M. Luo, Chair David L. Caudell William R. Huckle Tanya LeRoith

November 28, 2016 Blacksburg, VA

Keywords: Systemic lupus erythematosus, , lupus nephritis, B cell development

Selective HDAC6 Inhibition in Systemic Lupus Erythematosus

Miranda Diane Vieson

ACADEMIC ABSTRACT

Systemic lupus erythematosus (SLE) is a prototypic autoimmune disease characterized by abnormalities in multiple components of the immune system resulting in progressive damage to multiple organs. Current treatments for SLE are often intensive and result in side effects and the potential for continued flares and progression of disease. Histone deacetylase (HDAC) control multiple cellular functions by removing acetyl groups from lysine residues in various proteins. HDAC inhibitors have been investigated as a potential treatment for SLE with promising results, however selective HDAC6 inhibition (HDAC6i) has become a leading candidate for pharmacologic inhibition to reduce the potential for side effects. We hypothesize that HDAC6i will decrease SLE disease by targeting substrates of HDAC6 in multiple components of immunity and organ systems. NZB/W mice were treated with ACY-738 or

ACY-1083, followed by evaluation of multiple disease parameters and mechanisms involved in disease pathogenesis within the kidney, bone marrow, and spleen. Within the kidney, HDAC6i decreased glomerular pathology scores, proteinuria, and IgG and C3 deposition. Within glomerular cells, HDAC6i increased alpha- and decreased nuclear NF-κB.

Within the spleen, there was a dose-dependent decrease in the frequency of Th17 cells and a mild decrease in the frequency of Treg cells. Concurrently, there were decreased levels of IL-

12/IL-23 and minimal decreases in TGF-β in the serum. Within the bone marrow, B cell development through Hardy fractions exhibited accelerated progression through later stages as

NZB/W mice aged. This accelerated progression may allow B cells to bypass important regulatory checkpoints in maintaining immune tolerance and contribute to autoimmunity.

Treatment with an HDAC6i corrected the aberrant B cell development in the bone marrow and

RNAseq analysis unveiled six (Cebpb, Ccr9, Spib, Nfil3, Lgals1, and Pou2af1) that may play a role in the aforementioned abnormalities. Overall, these findings show that HDAC6i decreased disease in NZB/W mice by targeting multiple components of the immune response, including glomerular cells, T cell subsets in the spleen, and bone marrow B cells. In conclusion, selective HDAC6i is an excellent candidate for pharmacologic therapy for SLE because it targets multiple immune abnormalities involved in SLE pathogenesis while remaining selective and safe.

Selective HDAC6 Inhibition in Systemic Lupus Erythematosus

Miranda Diane Vieson

PUBLIC ABSTRACT

Systemic Lupus Erythematosus (SLE) is an autoimmune disease characterized by multiple abnormalities in the immune system resulting in progressive immune-mediated damage to multiple organs. Current treatment regimens are often intensive, result in side effects, and may only provide temporary relief of disease. Histone deacetylase (HDAC) inhibition is currently being investigated as a new treatment modality for SLE with aims for improved efficacy and decreased potential for unwanted side effects. HDAC enzymes remove acetyl groups from multiple proteins (substrates) and subsequently regulate their function.