C22-bronchial and T7-alveolar epithelial cell lines of the immortomouse are excellent murine cell culture model systems to study pulmonary peroxisome biology and metabolism

Abstract

In pulmonary research, temperature-sensitive immortalized cell lines derived from the lung of the "immortomouse" (H-2k(b)-tsA58 transgenic mouse), such as C22 club cells and T7 alveolar epithelial cells type II (AECII), are frequently used cell culture models to study CC10 metabolism and surfactant synthesis. Even though peroxisomes are highly abundant in club cells and AECII and might fulfill important metabolic functions therein, these organelles have never been investigated in C22 and T7 cells. Therefore, we have characterized the peroxisomal compartment and its associated gene transcription in these cell lines. Our results show that peroxisomes are highly abundant in C22 and T7 cells, harboring a common set of enzymes, however, exhibiting specific differences in protein composition and gene expression patterns, similar to the ones observed in club cells and AECII in situ in the lung. C22 cells contain a lower number of larger peroxisomes, whereas T7 cells possess more numerous tubular peroxisomes, reflected also by higher levels of PEX11 proteins. Moreover, C22 cells harbor relatively higher amounts of catalase and antioxidative enzymes in distinct subcellular compartments, whereas T7 cells exhibit higher levels of ABCD3 and plasmalogen synthesizing enzymes as well as nuclear receptors of the PPAR family. This study suggest that the C22 and T7 cell lines of the immortomouse lung are useful models to study the regulation and metabolic function of the peroxisomal compartment and its alterations by paracrine factors in club cells and AECII.

PPARα-mediated peroxisome induction compensates PPARγ-deficiency in bronchiolar club cells

“…Total RNA was isolated from microdissected bronchial epithelial cells using the RNeasy Plus Qiagen kit. The reverse-transcription was performed as previously described [ 12 ].…”

“…The C22 cells were maintained as previously described [ 12 ]. Briefly, the cells were maintained in permissive conditions (Dulbecco’s modified Eagle’s medium (DMEM) maintained in 2% fetal bovine serum (FBS), 100 U/ml penicillin, 1% streptomycin, 250 μg/ml amphotericin B, 5 μg/ml transferrin, 100 U/ml γ-INF, 10 μg/ml insulin, 0.025 μg/ml epidermal growth factor, 7.5 μg/ml endothelial cell growth supplement, 40 nmol/ml endothelin-1, 0.36 μg/ml hydrocortisone, 20 ng/ml T3) at 33°C.…”