RESEARCH ARTICLE: Selenite Stimulates Mitochondrial Biogenesis Signaling and Enhances Mitochondrial Functional Performance in Murine Hippocampal Neuronal Cells

OPEN ACCESS PEER-REVIEWED * Published: October 22, 2012

Authors: Natalia Mendelev ,Suresh L. Mehta ,Haza Idris,Santosh Kumari,P. Andy Li 


The objectives of this study are to examine whether supplementation of selenium stimulates mitochondrial biogenesis signaling pathways and whether selenium enhances mitochondrial functional performance. Murine hippocampal neuronal HT22 cells were treated with sodium selenite for 24 hours.


Mitochondria are both the powerhouse and source of ROS (Reactive oxygen species) production in cells. Pathological conditions that cause increased free radical production instigate mitochondrial damage, resulting in release of proapoptotic factors that subsequently activate intrinsic apoptotic cell death pathways. Mitochondrial biogenesis, the process by which new mitochondria are formed, is activated in response to cellular stress. Peroxisome proliferator-activated receptor (PPAR) gamma coactivator-1 (PGC-1α and PGC-1β) and nuclear respiratory factors (NRF1 and NRF2) are master regulators of mitochondrial biogenesis [11].We hypothesize that selenium may stimulate the mitochondrial biogenesis signaling pathway and enhance mitochondrial functional performance. To test this hypothesis, we measured nuclear mitochondrial biogenesis regulating factors PGC-1α and NRF1, levels of mitochondrial proteins, and functions of mitochondria and activities of respiratory complexes in selenite- and non-selenite-treated mural hippocampal HT22 neuronal cells. Our results demonstrate that supplementation of selenium significantly increases the levels of mitochondrial biogenesis markers and mitochondrial protein levels, and improves mitochondrial functional performance and respiratory complex activities.


Selenium increases mitochondrial biogenesis markers and mitochondrial proteins

The two key nuclear transcriptional factors, PGC-1α and NRF1, were used to evaluate the effects of selenium on mitochondrial biogenesis. As shown in Fig. 1, treatment of HT22 cells with 100 nM selenite for 24 h resulted in a 50% increase of protein levels of PGC-1α and NRF1 in the nuclear fraction.

Figure 1. Supplementation of selenium enhances protein levels of mitochondrial biogenesis markers, PGC-1α and NRF1, in the nuclear fractions.

To verify whether elevation of nuclear PGC-1α and NRF1 increases mitochondrial mass, we measured two mitochondrial proteins, cytochrome c and COX IV. As demonstrated in Fig. 2, selenite treatment increased both proteins in the mitochondrial fraction.

Figure 2. Selenite increases mitochondrial proteins.

Selenium improves mitochondrial respiration and complex activities

To determine whether the stimulation of mitochondrial biogenesis by selenium leads to any functional gain of the mitochondria, we measured mitochondrial oxygen consumption and calculated mitochondrial respiratory rate. Our results showed that selenium treatment of HT22 cells resulted in increased oxygen consumption, thereby improving the mitochondrial respiratory rate compared with non-selenium treated cells. Thus, selenium treatment increased the respiration rate by ∼36% in HT22 cells (Fig. 3).

Figure 3. Selenite enhances mitochondrial respiration in HT22 cells.

To further studied whether increased mitochondrial respiration is related to an increase in the activity of mitochondrial complexes, we measured oxygen utilization using complex specific substrates and calculated the activities of each mitochondrial respiratory complex from the difference in oxygen content reduction in the presence of specific respiratory complex inhibitors. As shown in Fig.4, selenite treatment not only increased activity of complex I, II+III and IV in cells by 50, 60, and 85%, respectively, but also increased the activities per milligram of protein, suggesting that besides mitochondrial biogenesis, selenium may also increase the efficiency of each complex. 

Figure 4. Selenite increases the activities of mitochondrial respiratory complexes I, II+III and IV.


It is generally believed that selenium exerts most or all of its protective effects by incorporating into selenoproteins as the amino acid selenocysteine. Although the functions of many selenoproteins remain to be characterized, some of them, such as GPXs, TRXRs, and selenoprotein P regulate redox signaling [30]–[33]. Our data show that selenite increases translation of PGC-1α and NRF1, two key regulators stimulating mitochondrial biogenesis. Subsequently, levels of two mitochondrial proteins, cytochrome c and COX IV, are increased in Se-treated cells comparing with non-treated controls, suggesting that increased mitochondrial biogenesis signal has led to enhancement of mitochondrial protein synthesis.

Research results revealed that treatment of selenium to the HT22 cells elevated the levels of nuclear mitochondrial biogenesis regulators PGC-1α and NRF1, as well as mitochondrial proteins cytochrome c and cytochrome c oxidase IV (COX IV). Supplementation of selenium significantly increased mitochondrial respiration and improved the activities of mitochondrial respiratory complexes. We conclude that selenium activates mitochondrial biogenesis signaling pathway and improves mitochondrial function.

Mitochondria play key roles in cell survival and death. Mitochondrial deterioration is a major pathophysiology of the aging process. Mitochondria initiate an intrinsic cell death pathway after being stressed. Therefore, preserving mitochondrial function by selenium may slow down the aging process and ameliorate cell death induced by various stress factors such as hypoxia, stroke, and inflammation. Indeed, published studies have reported that dietary selenium protects against selected signs of ageing [39], enhances ATP production in traumatic brain injury [40], increases the activities of mitochondrial respiratory chain complexes II, III, and IV [41] and inhibits mitochondria-initiated activation of the capase-9 and caspase-3 cell death pathway [10] after oxidative stress or hypoxic/ischemic injuries.

  1. Papp LV, Lu J, Holmgren A, Khanna KK (2007) From selenium to selenoproteins: synthesis, identity, and their role in human health. Antioxid Redox Signal 9: 775–806.
  2. Panee J, Stoytchev ZR, Liu W, Berry MJ (2007) Selenoprotein H is a redox-sensing high mobility group family DNA-binding protein that up-regulates genes involved in glutathione synthesis and phase II detoxification. J Biol Chem 282: 23759–23765.
  3. Hoffmann PR, Jourdan-Le Saux C, Hoffmann FW, Chang PS, Bollt O, et al. (2007) A role for dietary selenium and selenoproteins in allergic airway inflammation. J Immunol 179: 3258–3267.
  4. Porciuncula LO, Rocha JB, Boeck CR, Vendite D, Souza DO (2001) Ebselen prevents excitotoxicity provoked by glutamate in rat cerebellar granule neurons. Neurosci Lett 299: 217–220.
  5. Ozbal S, Erbil G, Kocdor H, Tugyan K, Pekcetin C, et al. (2008) The effects of selenium against cerebral ischemia-reperfusion injury in rats. Neurosci Lett 438: 265–269.
  6. Santamaria A, Vazquez-Roman B, La Cruz VP, Gonzalez-Cortes C, Trejo-Solis MC, et al. (2005) Selenium reduces the proapoptotic signaling associated to NF-kappaB pathway and stimulates glutathione peroxidase activity during excitotoxic damage produced by quinolinate in rat corpus striatum. Synapse 58: 258–266.
  7. Yamaguchi T, Sano K, Takakura K, Saito I, Shinohara Y, et al. (1998) Ebselen in acute ischemic stroke: a placebo-controlled, double-blind clinical trial. Ebselen Study Group. Stroke 29: 12–17
  8. Yousuf S, Atif F, Ahmad M, Hoda MN, Khan MB, et al. (2007) Selenium plays a modulatory role against cerebral ischemia-induced neuronal damage in rat hippocampus. Brain Res 1147: 218–225.
  9. Stapleton SR (2000) Selenium: an insulin-mimetic. Cell Mol. Life Sci 57: 1874–1879.
  10. Yoon SO, Kim MM, Park SJ, Kim D, Chung J, et al. (2002) Selenite suppresses hydrogen peroxide-induced cell apoptosis through inhibition of ASK1/JNK and activation of PI3-K/Akt pathways. Faseb J 16: 111–113.
  11. Bergeron R, Ren JM, Cadman KS, Moore IK, Perret P, et al. (2004) Chronic activation of AMP kinase results in NRF-1 activation and mitochondrial biogenesis. Am J Physiol Endocrinol Metab 281: E1340–1346.
  12. Kelly DP, Scarpulla RC (2004) Transcriptional regulatory circuits controlling mitochondrial biogenesis and function. Genes Dev 18: 357–368.
  13. Scarpulla RC (2002) Nuclear activators and coactivators in mammalian mitochondrial biogenesis. Biochim Biophys Acta 1576: 1–14.
  14. Scarpulla RC (2002) Transcriptional activators and coactivators in the nuclear control of mitochondrial function in mammalian cells. Gene 286: 81–89.
  15. Scarpulla RC (2008) Nuclear control of respiratory chain expression by nuclear respiratory factors and PGC-1-related coactivator. Ann N Y Acad Sci 1147: 321–334.
  16. Wu Z, Puigserver P, Andersson U, Zhang C, Adelmant G, et al. (1999) Mechanisms controlling mitochondrial biogenesis and respiration through the thermogenic coactivator PGC-1. Cell 98: 115–124.
  17. Panee J, Liu W, Nakamura K, Merry MJ (2007) The responses of HT22 cells to the blockade of mitochondrial complexes and potential protective effect of selenium supplementation. Int J Biol Sci 3: 335–341.
  18. Stone CA, Kawai K, Kupka R, Fawzi WW (2010) Role of selenium in HIV infection. Nutr Rev 68: 671–681.
  19. Ahmad A, Khan MM, Ishrat T, Khan MB, Khuwaja G, et al. (2011) Synergistic effect of selenium and melatonin on neuroprotection in cerebral ischemia in rats. Biol. Trace Elem Res 139: 81–96.
  20. Ansari MA, Ahmad AS, Ahmad M, Salim S, Yousuf S, et al. (2004) Selenium protects cerebral ischemia in rat brain mitochondria. Biol Trace Elem Res 101: 73–86.
  21. Bordoni A, Biagi PL, Angeloni C, Leoncini E, Danesi F, et al. (2005) Susceptibility to hypoxia/reoxygenation of aged rat cardiomyocytes and its modulation by selenium supplementation. J Agric Food Chem 53: 490–494.
  22. Wang Q, Zhang QG, Wu DN, Yin XH, Zhang GY (2007) Neuroprotection of selenite against ischemic brain injury through negatively regulating early activation of ASK1/JNK cascade via activation of PI3K/AKT pathway. Acta Pharmacol. Sin 28: 19–27.
  23. Wang Y, Ji HX, Zheng JN, Pei DS, Hu SQ, et al. (2009) Protective effect of selenite on renal ischemia/reperfusion injury through inhibiting ASK1-MKK3-p38 signal pathway. Redox Rep 14: 243–150.
  24. Jackson-Rosario SE, Self WT (2010) Targeting selenium metabolism and selenoproteins: novel avenues for drug discovery. Metallomics 2: 112–116.
  25. Papp LV, Holmgren A, Khanna KK (2010) Selenium and selenoproteins in health and disease. Antioxid Redox Signal 12: 793–795.
  26. Xiao R, Qiao JT, Zhao HF, Liang J, Yu HL, et al. (2006) Sodium selenite induces apoptosis in cultured cortical neurons with special concomitant changes in expression of the apoptosis-related genes. NeuroToxicology 27: 478–484.
  27. Maraldi T, Riccio M, Zambonin L, Vinceti M, De Pol A, et al. (2011) Low levels of selenium compounds are selectively toxic for a human neuron cell line through ROS/RNS increase and apoptotic process activation. NeuroToxicology 32: 180–187.
  28. Kumari S, Mehta SL, LI PA (2012) Glutamate induces mitochondrial dynamic imbalance and autophagy activation: preventive effects of selenium. PloS one 7: e39382.
  29. Mehta SL, Kumari S, Mendelev N, Li PA (2012) Selenium preserves mitochondrial function, stimulates mitochondrial biogenesis, and reduces infarct volume after focal cerebral ischemia. BMC neuroscience 13:79. Epub ahead of print.
  30. Kabuyama Y, Oshima K, Kitamura T, Homma M, Yamaki J, et al. (2007) Involvement of selenoprotein P in the regulation of redox balance and myofibroblast viability in idiopathic pulmonary fibrosis. Genes Cells 12: 1235–1244.
  31. Maher P (2006) Redox control of neural function: background, mechanisms, and significance. Antioxid Redox Signal 8: 1941–1970.
  32. 3McLean CW, Mirochnitchenko O, Claus CP, Noble-Haeusslein LJ, Ferriero DM (2005) Overexpression of glutathione peroxidase protects immature murine neurons from oxidative stress. Dev Neurosci 27: 169–175.
  33. Mitsui A, Hamuro J, Nakamura H, Kondo N, Hirabayashi Y, et al. (2002) Overexpression of human thioredoxin in transgenic mice controls oxidative stress and life span. Antioxid Redox Signal 4: 693–696.
  34. Sarker KP, Biswas KK, Rosales JL, Yamaji K, Hashiguchi T, et al. (2003) Ebselen inhibits NO-induced apoptosis of differentiated PC12 cells via inhibition of ASK1-p38 MAPK-p53 and JNK signaling and activation of p44/42 MAPK and Bcl-2. J Neurochem 87: 1345–1353.
  35. Wojewoda M, Duszynski J, Szczepanowska J (2011) NARP mutation and mtDNA depletion trigger mitochondrial biogenesis which can be modulated by selenite supplementation. Int J Biochem Cell Biol 43: 1178–1186.
  36. Rosner M, Hanneder M, Freilinger A, Hengstschlager M (2007) Nuclear and cytoplamic localization of Akt in the cell cycle. Amino Acids 32: 341–245.
  37. 3Ahmad N, Wang Y, Haider KH, Wang B, Pasha Z, et al. (2006) Cardiac protection by mitoKATP channels is dependent on Akt translocation from cytosol to mitochondria during late preconditioning. Am J Physiol Heart Circ Physiol 290: H2402–H2408.
  38. Jung U, Zheng X, Yoon SO, Chung AS (2001) Se-methylselenocysteine induces apoptosis mediated by reactive oxygen species in HL-60 cells. Free Radic Biol Med 31: 479–489.
  39. Heath JC, Banna KM, Reed MN, Pesek EF, Cole N, et al. (2010) Dietary selenium protects against selected signs of aging and methylmercury exposure. Neurotoxicology 31: 169–179.
  40. Yeo JE, Kang SK (2007) Selenium effectively inhibits ROS-mediated apoptotic neural precursor cell death in vitro and in vivo in traumatic brain injury. Biochim Biophys Acta 1772: 1199–1210.
  41. Desai VG, Casciano D, Feuers RJ, Aidoo A (2001) Activity profile of glutathione-dependent enzymes and respiratory chain complexes in rats supplemented with antioxidants and treated with carcinogens. Arch Biochem Biophys 394: 255–264.