Duplicated CA1 and CA3 domains are generated in the ventral hippocampus of RXCre/+; CIIF/F mutant mice.

A, The expression of COUP-TFI (a, d, g, j, m) and COUP-TFII (b, e, h, k, n) in coronal sections (a-f) and sagittal sections (g-o) of the hippocampus at postnatal month 1 (1M); representative Western blots and quantitative densitometry data for the expression of COUP-TFI and COUP-TFII in the dorsal and ventral hippocampus at 1M (p-q). B, In coronal sections along the rostrocaudal axis (a-f) and sagittal sections along the lateral-medial axis (g-l) of the hippocampus in mutant mice, compared with that in control mice (a-c, g-i), the ectopic CA-like structure, indicated by the star, was observed in the ventral region in COUP-TFII gene mutant (RXCre/+; CIIF/F) mice at 1M (d-f, j-l). C, The expression of HuB and Ctip2 in the corresponding inserted area in a-f under a high magnification objective lens at 1M (g-r); compared with those of control mice (a-c, g-i, m-o), the duplicated HuB-positive CA3 domain, indicated by the star, and Ctip2-positive domains, indicated by the arrowhead, were specifically observed in the ventral hippocampus (d-f, p-r) but not in the dorsal hippocampus (d-f, j-l) of COUP-TFII mutant mice at 1M; Ctip2 positive AHi and MePD amygdaloid nuclei were barely observed in the COUP-TFII mutant mice, indicated by the arrows, instead of the ectopic CA domains at the prospective amygdaloid regions (e-f, q-r). Data are expressed as the mean ± SEM. Student’s t test, *P<0.05, **P<0.01. AHi, amygdalohippocampal area; AMY, amygdala nuclei; CTX, cortex; dCA1, dorsal CA1; dCA3, dorsal CA3; dDG, dorsal dentate gyrus; dHPC, dorsal hippocampus; MePD, posterodorsal part of the medial amygdaloid nucleus; PMCo, posteromedial cortical amygdaloid nucleus; vCA1, ventral CA1; vCA3, ventral CA3; vDG, ventral dentate gyrus; vHPC, ventral hippocampus. Scale bars, Aa-c, Ad-f, Aj-o, Cg-r, 100 μm; Ag-i, Ba-l, Ca-f, 200μm.

The specification and differentiation of the dorsal CA1 lineage failed with the dysplastic dorsal hippocampus in RXCre/+; CIF/F mutant mice.

A, In coronal sections along the rostrocaudal axis (a-f) and sagittal sections along the lateral-medial axis (g-l) of the hippocampus, compared with that of control mice (a-c, g-i), the dorsal hippocampus was shrunken, indicated by the star, in COUP-TFI gene mutant (RXCre/+;CIF/F) mice at 1M (d-f, j-l). B, The expression of HuB and Ctip2 in the corresponding inserted area in a-f under a high magnification objective lens at 1M (g-r); compared with that of control mice (a-c, g-i, m-o), the HuB-positive CA3 domain was reduced in the dorsal hippocampus, especially the Ctip2-positive dorsal CA1, which was barely detected in COUP-TFI mutant mice at 1M (d-f, j-l), while their expression in the ventral hippocampus was comparable between the controls and mutants (d-f, p-r). C, The expression of HuB and Wfs1 in the corresponding inserted area in a-f under a high magnification objective lens at 1M (g-r); the expression of HuB and the dCA1 marker Wfs1 in the control (a-c, g-i, m-o) and COUP-TFII mutant mice (d-f, j-l, p-r) at 1M. Wfs1-positive dorsal CA1 could not be detected in COUP-TFI mutant mice at 1M, as indicated by the arrowhead. dHPC, dorsal hippocampus; HPC, hippocampus; vHPC, ventral hippocampus. Scale bars, Aa-l, Ba-f, Ca-f, 200 μm; Bg-r, Cg-r, 100 μm.

Defects in the hippocampus in RXCre/+; CIF/F; CIIF/F double-gene mutant mice.

A, In coronal sections along the rostrocaudal axis, compared with control mice (a-d), the hippocampus was atrophic in RXCre/+; CIF/F; CIIF/F double mutant mice, indicated by the star, and an ectopic unknown nucleus was observed in the caudal plates, indicated by the arrowhead (e-h). B, Compared with that of control mice (a-c, g-i), the expression of HuB, Ctip2, and Prox1 was decreased in the hippocampus of COUP-TFI/-TFII double-gene mutant mice at 3 weeks postnatal (3W) (d-f, j-l). C, Compared with that of control mice (a-c, g-i), the expression of HuB could not be detected in the presumptive CA3 domain, and the expression of Ctip2 or Prox1 could not be detected in the presumptive DG domain of the prospective ventral hippocampus of RXCre/+; CIF/F; CIIF/F double mutant mice. Scale bars, Aa-h, 200 μm; Ba-l, Ca-l, 100 μm.

The impairment of hippocampal trisynaptic connectivity in COUP-TFII single-gene, COUP-TFI single-gene, and COUP-TFI/-TFII double-gene mutant mice.

A, The expression of Calretinin, Calbindin, and SMI312 in the ventral hippocampus of the control (a-b, e-f, i-j) and COUP-TFII single-gene mutant mice (c-d, g-h, k-l). B, The expression of Calretinin, Calbindin, and SMI312 in the dorsal hippocampus of the control (a-b, e-f, i-j) and COUP-TFI single-gene mutant mice (c-d, g-h, k-l). C, The expression of Calretinin, Calbindin, and SMI312 in the hippocampus of the control (a-b, e-f, i-j) and COUP-TFI/-TFII double-gene mutant mice (c-d, g-h, k-l). dHPC, dorsal hippocampus; HPC, hippocampus; vHPC, ventral hippocampus. Scale bars, Aa-l, Ba-l, Ca-l, 100 μm.

COUP-TF genes regulate the expression of key genes associated with early hippocampal development.

A, The expression profiles of genes involved in hippocampal development in control and the double mutant mice at E11.5. B, Compared with that of control mice (a-b, a’-b’, a’’-b’’, i-j, i’-j’, q-r, q’-r’), the expression of Lhx5 was reduced in double-mutant mice at E11.5 (c-d, c’-d’, c’’-d’’), E13.5 (k-l, k’-l’) and E14.5 (s-t, s’-t’); the expression of Lhx2 was comparable between the control and double-mutant mice at E11.5 (e-h, e’-h’); and compared with that of control mice (m-n, m’-n’, u-v, u’-v’), the expression of Lhx2 was increased in double-mutant mice at E13.5 (o-p, o’-p’) and E14.5 (w-x, w’-x’). C, Compared with that of control mice (a-b, a’-b’), the expression of Sox2 was normal in double-mutant mice at E14.5 (c-d, c’-d’); compared with that of control mice (e-f, e’-f’), the expression of Tbr2 was decreased in COUP-TF mutant mice at E14.5 (g-h, g’-h’); compared with that of control mice (i-j, i’-j’), the expression of NeuroD1 was reduced in double-mutant mice at E14.5 (k-l, k’-l’). D, Quantitative analysis of Tbr2-positive cells and NeuroD1-positive cells in Ce’-h’ and Ci’-l’. E, In the hippocampal primordium of the early embryo, COUP-TFI is expressed dorsally in the MP, and COUP-TFII is expressed ventrally in the CH. In the mature hippocampus, the expression of COUP-TFI is higher in the dorsal hippocampus, which is related to spatial learning and memory, and the expression of COUP-TFII is mainly in the ventral hippocampus, which is associated with emotion and anxiety (a). Our findings support a novel molecular mechanism by which COUP-TFI and COUP-TFII may cooperate to ensure the appropriate morphogenesis and functions of the hippocampus by modulating the Lhx5-Lhx2 axis (b). Data are expressed as the mean ± SEM. Student’s t test, **P<0.01. CH, cortical hem; ChP, choroid plexus; DP, dorsal pallium; HP, hippocampal primordium; MP, medial pallium. Scale bars, Ba-x, Ca-l, 200 μm.

The expression of COUP-TF genes in the early developing hippocampus and different conditional knock mouse models.

A, The expression of COUP-TFI and COUP-TFII genes in the forebrain at E10.5 (a-b) and E11.5 (c-d). B, The expression of COUP-TFI and COUP-TFII genes in the developing hippocampus at E12.5 (a-c), E14.5 (d-f), and P0 (g-l). C, Compared with that of control mice (a-c), COUP-TFII is efficiently deleted by RXCre recombinase in the hippocampus of COUP-TFII mutant mice at 1M (d-f); COUP-TFI is clearly deleted by RXCre recombinase in the hippocampus of COUP-TFI mutant mice at 1M (g-i). Compared with that of control mice (j-l), COUP-TFI and -TFII were efficiently deleted by RXCre recombinase at the hippocampal primordium, including the MP and CH, in COUP-TFI/-TFII double-mutant mice at E14.5 (m-o). D, Compared with that of the control mice (a-c, g-h), the expression of COUP-TFII was significantly decreased in the hippocampal primordium of the homozygous mutant mice at E11.5; meanwhile, the LacZ signals obviously increased in the COUP-TFII homozygous mutant mice at E11.5 (d-f, j-k). Compared with that of the control mice (i), the expression of COUP-TFI is activated in the caudal hippocampal primordium of the homozygous mutant mice at E11.5 (l). CH, cortical hem; dHPC, dorsal hippocampus; HP, hippocampal primordium; HPC, hippocampus; MP, medial pallium; vHPC, ventral hippocampus. Scale bars, Aa-d, Ba-f, Cj-o, 200 μm; Bg-l, Ca-i, Dg-l, 100 μm; Da-f, 250 μm.

Defects in Emx1Cre/+; COUP-TFIF/F mutant mice.

A, Immunofluorescence staining data showed that compared with those of control mice (a, c, e, g), the proportions of either the Wfs1- or Ctip2-positive dorsal CA1 domain were reduced in Emx1Cre/+; COUP-TFIF/F mutant mice at 3M (b, d, f, h). B, Golgi staining showed that compared with those of controls, the numbers of branch points and secondary dendrites of both apical and basal dendrites were significantly reduced in the dorsal hippocampal CA1 pyramidal neurons of Emx1Cre/+; COUP-TFIF/F mutant mice (a-c). C, The Morris water maze behavior test showed that compared with that of controls, spatial learning and memory were significantly damaged in Emx1Cre/+; COUP-TFIF/F mutant mice. Data are expressed as the mean ± SEM. Student’s t test, *P<0.05, **P<0.01, ***P<0.001. Scale bars, Aa-h, 100 μm; Ba-b, 50 μm.

Adult neurogenesis was abnormal in the hippocampi of COUP-TFI/-TFII double-gene mutant mice.

A, The expression of GFAP and Nestin, markers of NSCs, in the SGZ of the vDG in control and COUP-TFII mutant mice at 1M (a-h), in the SGZ of the dDG in control and COUP-TFI mutant mice at 1M (i-p) and in the SGZ of the DG in control and COUP-TFI/-TFII double-gene mutant mice at 3W (q-x). B, The expression of Dcx, a marker of newborn neurons, in the SGZ of the vDG in control and COUP-TFII mutant mice at 1M (a-d), in the SGZ of the dDG in control and COUP-TFI mutant mice at 1M (e-h) and in the SGZ of the DG in control and COUP-TFI/-TFII double-gene mutant mice at 3W (i-l). C, Quantitative analysis of GFAP/Nestin-positive cells (a) and Dcx-positive cells (b) in the SGZ of the DG in control and COUP-TFI/-TFII double-gene mutant mice at 3W. The numbers of GFAP and Nestin double-positive NSCs and Dcx-positive newborn neurons were significantly reduced in double-mutant mice. Data are expressed as the mean ± SEM. Student’s t test, **P<0.01, ***P<0.001. dDG, dorsal DG; NSC, neural stem cell; SGZ, subgranular zone; vDG, ventral DG. Scale bars, Aa-x, 50 μm; Ba-l, 100 μm.

COUP-TFI and -TFII genes coordinate to control distinct characteristics of the hippocampus.

Roles of COUP-TFI and COUP-TFII genes in the development and function of the hippocampus and the association with neurological diseases. COUP-TFI is required for the morphogenesis of the dorsal hippocampus and the specification of dorsal CA1 pyramidal neuron lineage, which are associated with neurodevelopmental disorders, including ID and ASD. COUP-TFII is required to prevent the duplication of the CA1 and CA3 lineages of the ventral hippocampus, which may be related to psychiatric diseases such as depression, anxiety, or schizophrenia. The COUP-TFI and COUP-TFII genes are novel intrinsic regulatory genes, which cooperate with each other to ensure the early morphogenesis of the hippocampus.