Which has more stem-cell characteristics: Müller cells or Müller cells derived from in vivo culture in neurospheres?
OBJECTIVE
Müller cells can be acquired from in vitro culture or a neurosphere culture system. Both culture methods yield cells with progenitor-cell characteristics that can differentiate into mature nervous cells. We compared the progenitor-cell traits of Müller cells acquired from each method.


METHODS
Primary murine Müller cells were isolated in serum culture media and used to generate Müller cells derived from neurospheres in serum-free culture conditions. Gene expression of neural progenitor cell markers was examined by Q-PCR in the two groups. Expression of rhodopsin and the cone-rod homeobox protein CRX were assessed after induction with 1 μM all-trans retinoic acid (RA) for 7 days.


RESULTS
After more than four passages, many cells were large, flattened, and difficult to passage. A spontaneously immortalized Müller cell line was not established. Three-passage neurospheres yielded few new spheres. Genes coding for Nestin, Sox2, Chx10, and Vimentin were downregulated in cells derived from neurospheres compared to the cells from standard culture, while Pax6 was upregulated. Müller cells from both culture methods were induced into rod photoreceptors, but expression of rhodopsin and CRX was greater in the Müller cells from the standard culture.


CONCLUSIONS
Both culture methods yielded cells with stem-cell characteristics that can be induced into rod photoreceptor neurons by RA. Serum had no influence on the "stemness" of the cells. Cells from standard culture had greater "stemness" than cells derived from neurospheres. The standard Müller cells would seem to be the best choice for transplantation in cell replacement therapy for photoreceptor degeneration.
Department of Ophthalmology, Xiangya Hospital, Central South UniversityChangsha 410008, China; Department of Ophthalmology, The People's Hospital of Guizhou ProvinceGuiyang 550002, China.
Hong-Pei
HP
Ji
Department of Ophthalmology, Xiangya Hospital, Central South University Changsha 410008, China.
Yu
Y
Xiong
Department of Ophthalmology, Xiangya Hospital, Central South University Changsha 410008, China.
En-Dong
ED
Zhang
Department of Ophthalmology, Xiangya Hospital, Central South University Changsha 410008, China.
Wei-Tao
WT
Song
Department of Ophthalmology, Xiangya Hospital, Central South University Changsha 410008, China.
Zhao-Lin
ZL
Gao
Department of Ophthalmology, Xiangya Hospital, Central South University Changsha 410008, China.
Fei
F
Yao
Department of Ophthalmology, Xiangya Hospital, Central South University Changsha 410008, China.
Hong
H
Sun
Department of Oncology, Xiangya Hospital, Central South University Changsha 410008, China.
Rong-Rong
RR
Zhou
Department of Ophthalmology, Xiangya Hospital, Central South University Changsha 410008, China.
Xiao-Bo
XB
Xia
Müller cells; Stemness; neurospheres