Presentation Title

Group A Streptococcus Decreases Vacuolar ATPase Assembly in THP-1 Macrophages

Faculty Mentor

Cheryl Okumura

Start Date

17-11-2018 8:30 AM

End Date

17-11-2018 10:30 AM

Location

CREVELING 93

Session

POSTER 1

Type of Presentation

Poster

Subject Area

biological_agricultural_sciences

Abstract

Infection with Group A Streptococcus (GAS), a Gram-positive bacterial pathogen, leads to a multitude of diseases, ranging from strep throat to toxic shock, and leads to extremely serious subsequent diseases such as rheumatic heart disease. Normally during infection, macrophages phagocytose bacteria, and phagosomal fusion with the lysosome and degradation by proteolytic enzymes are expected to destroy GAS. However, we and others have found GAS survives in macrophage phagosomes. The overall objective therefore is to establish the mechanisms through which GAS is able to survive degradation from proteolytic enzymes in macrophage phagolysosomes. Activation of the proteolytic enzymes of the lysosome requires acidification by the vacuolar proton-translocating adenosine triphosphate (V-ATPase), which needs to properly assemble to function. My research specifically focuses on determining the effects of GAS infection on V-ATPase assembly in THP-1 macrophages. Macrophages were treated with the control or GAS infection conditions, lysed, and separated into cytosolic and membrane fractions. SDS-PAGE and Western blot experiments were then run to help determine the effects of GAS infection on assembly by monitoring the cellular location of the V1A cytosolic subunit of the V-ATPase complex. A shift in the abundance of V1A (quantified via volume intensity from Western blot images) from the cytosolic fractions to the membrane fractions occurred to a lesser degree in GAS-infected cells compared to control conditions. Ultimately, these findings indicated that the infection of GAS causes decreased levels of V-ATPase assembly in THP-1 macrophages. These findings are relevant because discerning the methods through which GAS persists in macrophage phagolysosomes will facilitate efforts to provide alternatives to antibiotics to combat the burdens of GAS infection.

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Nov 17th, 8:30 AM Nov 17th, 10:30 AM

Group A Streptococcus Decreases Vacuolar ATPase Assembly in THP-1 Macrophages

CREVELING 93

Infection with Group A Streptococcus (GAS), a Gram-positive bacterial pathogen, leads to a multitude of diseases, ranging from strep throat to toxic shock, and leads to extremely serious subsequent diseases such as rheumatic heart disease. Normally during infection, macrophages phagocytose bacteria, and phagosomal fusion with the lysosome and degradation by proteolytic enzymes are expected to destroy GAS. However, we and others have found GAS survives in macrophage phagosomes. The overall objective therefore is to establish the mechanisms through which GAS is able to survive degradation from proteolytic enzymes in macrophage phagolysosomes. Activation of the proteolytic enzymes of the lysosome requires acidification by the vacuolar proton-translocating adenosine triphosphate (V-ATPase), which needs to properly assemble to function. My research specifically focuses on determining the effects of GAS infection on V-ATPase assembly in THP-1 macrophages. Macrophages were treated with the control or GAS infection conditions, lysed, and separated into cytosolic and membrane fractions. SDS-PAGE and Western blot experiments were then run to help determine the effects of GAS infection on assembly by monitoring the cellular location of the V1A cytosolic subunit of the V-ATPase complex. A shift in the abundance of V1A (quantified via volume intensity from Western blot images) from the cytosolic fractions to the membrane fractions occurred to a lesser degree in GAS-infected cells compared to control conditions. Ultimately, these findings indicated that the infection of GAS causes decreased levels of V-ATPase assembly in THP-1 macrophages. These findings are relevant because discerning the methods through which GAS persists in macrophage phagolysosomes will facilitate efforts to provide alternatives to antibiotics to combat the burdens of GAS infection.