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Gene Review

Hmox2  -  heme oxygenase (decycling) 2

Mus musculus

Synonyms: HO-2, HO2, Heme oxygenase 2
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Disease relevance of Hmox2


Psychiatry related information on Hmox2


High impact information on Hmox2


Chemical compound and disease context of Hmox2

  • Importantly, HO-2(-/-) mice exhibit normal breathing patterns with normal arterial CO2 tension and retain the intact alveolar architecture, thereby excluding hypoventilation and shunting as causes of hypoxemia [7].
  • HO-2(-/-) mice also show attenuated ventilatory responses to hypoxia (10% O2) with normal responses to hypercapnia (10% CO2), suggesting the impaired oxygen sensing [7].
  • Bilirubin itself in nanomolar concentrations is neuroprotective, while HO2 deletion (HO2(-/-)) leads to increased neurotoxicity in brain cultures and increased neural damage following transient cerebral ischemia in intact mice [8].
  • Hyperglycemia was induced by streptozotocin (STZ) injection, and its effect on renal HO-1/HO-2 protein, HO activity, and creatinine levels were assessed [9].
  • We conclude that both HO-1 and HO-2 have anti-apoptotic effects against oxidative stress-related glutamate toxicity in cerebral vascular endothelium [10].

Biological context of Hmox2


Anatomical context of Hmox2

  • We utilized olfactory receptor neurons (ORNs) as a model to define the roles of HO-1 and HO-2 in neuronal development and survival, and to determine the mediators of these effects [11].
  • These roles for HO-1 and HO-2 were confirmed using detergent ablation of the epithelium to observe increased neurogenesis of ORNs after target disruption in HO null mice [11].
  • We now show that neural damage following middle cerebral artery occlusion (MCAO) and reperfusion, a model of focal ischemia of vascular stroke, is substantially worsened in HO2(-/-) animals [13].
  • In spinal cord slices from either nNOS or HO-2 null-mutant animals morphine did not stimulate cGMP production [15].
  • Here we show that HO-2-deficient (HO-2(-/-)) mice exhibit hypoxemia and hypertrophy of the pulmonary venous myocardium associated with increased expression of HO-1 [7].

Associations of Hmox2 with chemical compounds

  • Bilirubin immunostaining was reduced only in HO-2 null mice [11].
  • METHODS: After anesthesia was induced with isoflurane, 3- to 6-month-old HO-2 knockout and wild-type mice were stereotactically injected with 15 microl autologous blood and a group of control mice were injected with an equal volume of sterile saline [2].
  • We evaluated survival, indices of oxidative injury, and lung and HO expression in HO-2 null mutant mice exposed to > 95% O2 compared with wild-type controls [12].
  • Neural damage following intracranial injections of N-methyl-d-aspartate (NMDA) is also accentuated in HO2(-/-) animals [13].
  • We then determined that L-NAME loses its ability to potentiate morphine in nNOS null-mutant mice, while Sn-P no longer potentiates morphine in mice lacking a functional HO-2 gene [15].

Other interactions of Hmox2

  • Mice null for either HO-1 or HO-2 displayed decreased proliferation of neuronal precursors [11].
  • By using a combination of pharmacology and genetic knockout of the biosynthetic enzymes for CO and NO, we show that the physiologic effects of exogenous and endogenous VIP in the IAS are mediated by HO2-synthesized CO [16].
  • Other proteins examined (cyclooxygenase 2, heme oxygenase 2, heat shock protein 70, and glucose-regulated protein 78) were unaffected [17].
  • Among these, cortex showed the lowest levels of HO-2, Hsp70, GSSG and peroxides that were associated with the highest levels of GSH and GSH/GSSG ratio [18].
  • These studies showed that HO-2 null mutants had less Fos expression after stimulation by brushing than did their wild type counterparts [19].

Analytical, diagnostic and therapeutic context of Hmox2


  1. Effect of targeted deletion of the heme oxygenase-2 gene on hemoglobin toxicity in the striatum. Qu, Y., Chen, J., Benvenisti-Zarom, L., Ma, X., Regan, R.F. J. Cereb. Blood Flow Metab. (2005) [Pubmed]
  2. Attenuation of oxidative injury after induction of experimental intracerebral hemorrhage in heme oxygenase-2 knockout mice. Qu, Y., Chen-Roetling, J., Benvenisti-Zarom, L., Regan, R.F. J. Neurosurg. (2007) [Pubmed]
  3. Hypoxia induces severe right ventricular dilatation and infarction in heme oxygenase-1 null mice. Yet, S.F., Perrella, M.A., Layne, M.D., Hsieh, C.M., Maemura, K., Kobzik, L., Wiesel, P., Christou, H., Kourembanas, S., Lee, M.E. J. Clin. Invest. (1999) [Pubmed]
  4. Site of injury-directed induction of heme oxygenase-1 and -2 in experimental spinal cord injury: differential functions in neuronal defense mechanisms? Panahian, N., Maines, M.D. J. Neurochem. (2001) [Pubmed]
  5. Ejaculatory abnormalities in mice with targeted disruption of the gene for heme oxygenase-2. Burnett, A.L., Johns, D.G., Kriegsfeld, L.J., Klein, S.L., Calvin, D.C., Demas, G.E., Schramm, L.P., Tonegawa, S., Nelson, R.J., Snyder, S.H., Poss, K.D. Nat. Med. (1998) [Pubmed]
  6. Carbon monoxide neurotransmission activated by CK2 phosphorylation of heme oxygenase-2. Boehning, D., Moon, C., Sharma, S., Hurt, K.J., Hester, L.D., Ronnett, G.V., Shugar, D., Snyder, S.H. Neuron (2003) [Pubmed]
  7. Hypoxemia and blunted hypoxic ventilatory responses in mice lacking heme oxygenase-2. Adachi, T., Ishikawa, K., Hida, W., Matsumoto, H., Masuda, T., Date, F., Ogawa, K., Takeda, K., Furuyama, K., Zhang, Y., Kitamuro, T., Ogawa, H., Maruyama, Y., Shibahara, S. Biochem. Biophys. Res. Commun. (2004) [Pubmed]
  8. Heme oxygenase-2 acts to prevent neuronal death in brain cultures and following transient cerebral ischemia. Doré, S., Goto, S., Sampei, K., Blackshaw, S., Hester, L.D., Ingi, T., Sawa, A., Traystman, R.J., Koehler, R.C., Snyder, S.H. Neuroscience (2000) [Pubmed]
  9. Heme oxygenase-2 deficiency contributes to diabetes-mediated increase in superoxide anion and renal dysfunction. Goodman, A.I., Chander, P.N., Rezzani, R., Schwartzman, M.L., Regan, R.F., Rodella, L., Turkseven, S., Lianos, E.A., Dennery, P.A., Abraham, N.G. J. Am. Soc. Nephrol. (2006) [Pubmed]
  10. Glutamate induces oxidative stress and apoptosis in cerebral vascular endothelial cells: contributions of HO-1 and HO-2 to cytoprotection. Parfenova, H., Basuroy, S., Bhattacharya, S., Tcheranova, D., Qu, Y., Regan, R.F., Leffler, C.W. Am. J. Physiol., Cell Physiol. (2006) [Pubmed]
  11. Heme oxygenase-1 and heme oxygenase-2 have distinct roles in the proliferation and survival of olfactory receptor neurons mediated by cGMP and bilirubin, respectively. Chen, J., Tu, Y., Moon, C., Nagata, E., Ronnett, G.V. J. Neurochem. (2003) [Pubmed]
  12. Oxygen toxicity and iron accumulation in the lungs of mice lacking heme oxygenase-2. Dennery, P.A., Spitz, D.R., Yang, G., Tatarov, A., Lee, C.S., Shegog, M.L., Poss, K.D. J. Clin. Invest. (1998) [Pubmed]
  13. Heme oxygenase-2 is neuroprotective in cerebral ischemia. Doré, S., Sampei, K., Goto, S., Alkayed, N.J., Guastella, D., Blackshaw, S., Gallagher, M., Traystman, R.J., Hurn, P.D., Koehler, R.C., Snyder, S.H. Mol. Med. (1999) [Pubmed]
  14. Heme oxygenase-2 protects against lipid peroxidation-mediated cell loss and impaired motor recovery after traumatic brain injury. Chang, E.F., Wong, R.J., Vreman, H.J., Igarashi, T., Galo, E., Sharp, F.R., Stevenson, D.K., Noble-Haeusslein, L.J. J. Neurosci. (2003) [Pubmed]
  15. Spinal cord nitric oxide synthase and heme oxygenase limit morphine induced analgesia. Li, X., Clark, J.D. Brain Res. Mol. Brain Res. (2001) [Pubmed]
  16. Carbon monoxide mediates vasoactive intestinal polypeptide-associated nonadrenergic/noncholinergic neurotransmission. Watkins, C.C., Boehning, D., Kaplin, A.I., Rao, M., Ferris, C.D., Snyder, S.H. Proc. Natl. Acad. Sci. U.S.A. (2004) [Pubmed]
  17. Inhibition of inducible nitric oxide synthase by peroxisome proliferator-activated receptor agonists: correlation with induction of heme oxygenase 1. Colville-Nash, P.R., Qureshi, S.S., Willis, D., Willoughby, D.A. J. Immunol. (1998) [Pubmed]
  18. Regional distribution of heme oxygenase, HSP70, and glutathione in brain: relevance for endogenous oxidant/antioxidant balance and stress tolerance. Calabrese, V., Scapagnini, G., Ravagna, A., Fariello, R.G., Giuffrida Stella, A.M., Abraham, N.G. J. Neurosci. Res. (2002) [Pubmed]
  19. Heme oxygenase type 2 participates in the development of chronic inflammatory and neuropathic pain. Li, X., Clark, J.D. The journal of pain : official journal of the American Pain Society. (2003) [Pubmed]
  20. Expression and regulation of heme oxygenase isozymes in the developing mouse cortex. Zhao, H., Wong, R.J., Nguyen, X., Kalish, F., Mizobuchi, M., Vreman, H.J., Stevenson, D.K., Contag, C.H. Pediatr. Res. (2006) [Pubmed]
  21. Heme oxygenase is downregulated in stress-triggered and interleukin-12-mediated murine abortion. Zenclussen, A.C., Joachim, R., Hagen, E., Peiser, C., Klapp, B.F., Arck, P.C. Scand. J. Immunol. (2002) [Pubmed]
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