Role of haem oxygenase-1 in microbial host defence

Abstract

SummaryHeme oxygenase (HO)-1 is a cytoprotective enzyme that plays a critical role in defending the body against oxidant-induced injury during inflammatory processes. HO catalyzes the degradation of heme to carbon monoxide (CO), biliverdin, and ferrous iron. Biliverdin is converted to bilirubin, a potent endogenous antioxidant. CO has a number of biological functions, including anti-inflammatory properties. In various models of disease, HO-1 is known to play a critical role by ameliorating the pathological consequences of injury. In many of these models, the beneficial effects of HO-1 and its products of heme catabolism are by suppressing an inflammatory response. However, when investigating diseases due to microbial infections, inhibition of the inflammatory response could disrupt the ability of the immune system to eradicate an invading pathogen. Thus, questions remain regarding the role of HO-1 in microbial host defense. This microreview will address our present understanding of HO-1 and its functional significance in a variety of microbial infections.

Heme Oxygenase-1 and Carbon Monoxide PromoteBurkholderia pseudomalleiInfection

“…An appropriate balance of the inflammatory and redox states is essential to resolve most infections and finally the infectious process (21). However, the components of the inflammatory and oxidative stress response during melioidosis are unknown.…”

“…HO-1 is highly inducible by a variety of stimuli, such as LPS, inflammatory cytokines, heat shock, heavy metals, oxidants, and its substrate heme. It catalyzes the first and rate-limiting step in the degradation of heme (iron protoporphyrin IX) into CO, biliverdin, and ferrous iron (21). Its metabolite CO has various biological functions, including cytoprotective and anti-inflammatory properties (22,23).…”

“…The immunmodulatory effects can have both beneficial and detrimental consequences for the host immunity against infectious agents (21). HO-1 is able to promote Plasmodium liver infection (26), whereas it plays a favorable role in the host during cerebral malaria (27).…”

Down-regulation of heme oxygenase-1 by SVCV infection

“…Accumulated evidences have demonstrated that HO-1 has potent anti-oxidative, anti-inflammatory, and anti-apoptotic properties (reviewed in Refs. [1,2]). HO-1 has also been shown to interfere hepatitis C virus (HCV) [3e5], hepatitis B virus (HBV) [6] and human immunodeficiency virus (HIV) [7] infections.…”

MicroRNA miR-24-3p Promotes Porcine Reproductive and Respiratory Syndrome Virus Replication through Suppression of Heme Oxygenase-1 Expression

“…HO-1 and its end products have antioxidant, anti-inflammatory, and antiviral properties, and it is known to be a pivotal cytoprotective enzyme (12). Upregulation of HO-1 expression suppresses replication of a number of viruses, including hepatitis C virus (HCV), HIV-1, hepatitis B virus (HBV), and influenza virus (13)(14)(15)(16)(17).…”