R. Li

University of Pennsylvania Department of Neurology

Author Of 1 Presentation

Disease Modifying Therapies – Mechanism of Action Oral Presentation

YI01.02 - BTK inhibition results in preferential reduction of pro-inflammatory B-cell responses through modulation of B-cell metabolism

Speakers
Presentation Number
YI01.02
Presentation Topic
Disease Modifying Therapies – Mechanism of Action
Lecture Time
11:12 - 11:24

Abstract

Background

Results of B-cell depleting therapies have underscored important antibody-independent functions of B cells in multiple sclerosis (MS) pathogenesis. Bruton’s Tyrosine Kinase (BTK) is a key down-stream signaling molecule of the B cell receptor, and BTK inhibitors (BTKi) have been used for treating various B-cell malignancies. BTKi are now being pursued as a ‘next generation’ non-depleting approach to B-cell targeting in MS. However, the contributions of BTK to MS-relevant functional B-cell responses, and the impact of BTKi on such responses, remain largely unknown.

Objectives

We would like to assess the impact of BTK inhibition on MS implicated B-cell functions and explore underlying mechanisms.

Methods

We applied a series of functional assays and RNA sequencing to human B cells, isolated from peripheral blood of healthy individuals or MS patients, as well as from human tonsils, to study influence of BTKi on B-cell survival, activation, proliferation, antibody production, antigen presenting functions, cytokine production and metabolism.

Results

As expected, BTKi strongly decreased B-cell activation with minimal effects on B cell survival. BTKi also significantly limited the induction of co-stimulatory molecules (CD80, CD86) expression on activated B cells, which in turn resulted in a decreased capacity of the B cells to support both polyclonal as well as antigen-specific T-cell activation. Interestingly, BTKi treatment preferentially reduced pro-inflammatory B-cell cytokine (GM-CSF, TNFα and IL-6) secretion with only marginal influence on B-cell IL-10 production, resulting in a decreased capacity of the B cells to promote myeloid cell pro-inflammatory responses. Unbiased transcriptomic analysis of either vehicle- or BTKi-treated B cells suggested that BTKi could limit metabolism-related pathways, and subsequent seahorse analyzer experiments confirmed that BTKi decreased B-cell mitochondrial respiration and glycolysis. Metabolic manipulation further revealed that the level of mitochondrial respiration could control the balance between pro- and anti-inflammatory B cell responses.

Conclusions

BTKi preferentially limits pro-inflammatory B-cell responses that are implicated in MS pathophysiology. Our study also reveals a fundamental role for metabolism in regulating B-cell functions, and points to a novel therapeutic strategy targeting the balance between pro- and anti-inflammatory responses of B cells through modulation of their energy-utilization pathways.

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Presenter Of 1 Presentation

Disease Modifying Therapies – Mechanism of Action Oral Presentation

YI01.02 - BTK inhibition results in preferential reduction of pro-inflammatory B-cell responses through modulation of B-cell metabolism

Speakers
Presentation Number
YI01.02
Presentation Topic
Disease Modifying Therapies – Mechanism of Action
Lecture Time
11:12 - 11:24

Abstract

Background

Results of B-cell depleting therapies have underscored important antibody-independent functions of B cells in multiple sclerosis (MS) pathogenesis. Bruton’s Tyrosine Kinase (BTK) is a key down-stream signaling molecule of the B cell receptor, and BTK inhibitors (BTKi) have been used for treating various B-cell malignancies. BTKi are now being pursued as a ‘next generation’ non-depleting approach to B-cell targeting in MS. However, the contributions of BTK to MS-relevant functional B-cell responses, and the impact of BTKi on such responses, remain largely unknown.

Objectives

We would like to assess the impact of BTK inhibition on MS implicated B-cell functions and explore underlying mechanisms.

Methods

We applied a series of functional assays and RNA sequencing to human B cells, isolated from peripheral blood of healthy individuals or MS patients, as well as from human tonsils, to study influence of BTKi on B-cell survival, activation, proliferation, antibody production, antigen presenting functions, cytokine production and metabolism.

Results

As expected, BTKi strongly decreased B-cell activation with minimal effects on B cell survival. BTKi also significantly limited the induction of co-stimulatory molecules (CD80, CD86) expression on activated B cells, which in turn resulted in a decreased capacity of the B cells to support both polyclonal as well as antigen-specific T-cell activation. Interestingly, BTKi treatment preferentially reduced pro-inflammatory B-cell cytokine (GM-CSF, TNFα and IL-6) secretion with only marginal influence on B-cell IL-10 production, resulting in a decreased capacity of the B cells to promote myeloid cell pro-inflammatory responses. Unbiased transcriptomic analysis of either vehicle- or BTKi-treated B cells suggested that BTKi could limit metabolism-related pathways, and subsequent seahorse analyzer experiments confirmed that BTKi decreased B-cell mitochondrial respiration and glycolysis. Metabolic manipulation further revealed that the level of mitochondrial respiration could control the balance between pro- and anti-inflammatory B cell responses.

Conclusions

BTKi preferentially limits pro-inflammatory B-cell responses that are implicated in MS pathophysiology. Our study also reveals a fundamental role for metabolism in regulating B-cell functions, and points to a novel therapeutic strategy targeting the balance between pro- and anti-inflammatory responses of B cells through modulation of their energy-utilization pathways.

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