A Distinct Temporal Regulation of Cellular Bcl-2 Family Proteins Promotes Survival of HCMV-

Infected Monocytes

Donna Collins-McMillen, E.V. Stevenson, M.T. Nogalski, J. Caskey, G.C.T. Chan, and A.D. Yurochko

Louisiana State University Health – Shreveport, LA

Monocytes as Vehicles for Viral Spread

1. 2.

3.4.

5.6.

7.

Monocyte Survival Hurdle

MФmonocyte

Monocyte Survival Hurdle

MФmonocyte 48hpi

apoptotic programming

“default”

Monocyte Survival Hurdle

MФmonocyte 48hpi

“default” apoptotic programming

Anti-viral

pro-apoptotic response

HCMV Engages a Distinct Pro-Survival Mechanism to Prevent

Monocyte Apoptosis 1) Bi-phasic regulation of Mcl-1 and Bcl-2

2) Distinct & overlapping signaling through EGFR/integrins

3) Promotes survival at multiple apoptotic checkpoints • bypasses viability checkpoint at 48 h

(stabilizes Mcl-1, Chan et al., 2010)• adapts to anti-viral pro-apoptotic response

(Bcl-2 up in response to Bax)

Bi-Phasic Mcl-1/Bcl-2 Shift

Mcl-1 in HCMV-infected monocytes

MФmonocyte 48hpi

Mcl-1 Bcl-2

(1) (1.2)(1.4) (3.9)(1.9)(5.1) (2.0) (6.2))

Bcl-2 in HCMV-infected monocytes

Chan et al., 2010

Bi-Phasic Mcl-1/Bcl-2 Shift

• Bcl-2 controls late survival in HCMV-infected monocytes (Mcl-1 early, Chan et al., 2010)

• Mcl-1 and Bcl-2 are both required for early survival in mock-infected cells

HCMV Signaling Through EGFR/Integrins

Chan et al., 2010

Bcl-2 Combats the Anti-Viral Pro-Apoptotic Response (Bax Up-

Regulation)

MФmonocyte 48hpi

Mcl-1 Bcl-2

(1) (1.4) (1.2)(4) (2.8)(5.6)(3.3)(10.5))

Bcl-2 (but not Mcl-1) can bind & inactivate Bax

Bax Expression Drives Bcl-2 Up-Regulation

Bax Depletion Rescues Infected Bcl-2-Defective Cells From Apoptosis

AcknowledgementsMentorDr. Andrew Yurochko

Dissertation Committee

Dr. Robert ChervenakDr. Lindsey Hutt-FletcherDr. Dennis O’CallaghanDr. Kelly Tatchell Dr. Felicia Goodrum (U of AZ)

Funding:

Yurochko LabLiesl MilfordDr. Maciej NogalskiDr. Gary ChanDr. Emily Stevenson Dr. Yanjie LiStephen CieplyDr. Jung Heon KimJoshua Caskey

A156077P30GM110703

Pre-Doctoral Fellowship

14PRE20310027