Biologic that disrupts PDE11A4 homodimerization in hippocampus CA1 reverses age-related proteinopathies in PDE11A4 and cognitive decline of social memories

Abstract

Age-related proteinopathies in phosphodiesterase 11A (PDE11A), an enzyme that degrades 3,5-cAMP/cGMP and is enriched in the ventral hippocampal formation (VHIPP), drive age-related cognitive decline (ARCD) of social memories. In the VHIPP, age-related increases in PDE11A4 occur specifically within the membrane compartment and ectopically accumulate in filamentous structures termed ghost axons. Previous in vitro studies show that disrupting PDE11 homodimerization by expressing an isolated PDE11A-GAFB domain, which acts as a negative sink for monomers, selectively degrades membrane-associated PDE11A4 and prevents the punctate accumulation of PDE11A4. Therefore, we determined if disrupting PDE11A4 homodimerization in vivo via the expression of an isolated PDE11A4-GAFB domain would be sufficient to reverse 1) age-related accumulations of PDE11A4 in VHIPP ghost axons and 2) ARCD of social memories. Indeed, in vivo lentiviral expression of the isolated PDE11A4-GAFB domain in hippocampal CA1 reversed the age-related accumulation of PDE11A4 in ghost axons, reversed ACRD of social transmission of food preference memory (STFP), and improved remote long-term memory for social odor recognition (SOR) without affecting memory for non-social odor recognition. In vitro studies suggest that disrupting homodimerization of PDE11A4 does not directly alter the catalytic activity of the enzyme but may reverse age-related decreases in cGMP by dispersing the accumulation of the enzyme independently of other intramolecular mechanisms previously established to disperse PDE11A4 (e.g., phosphorylation of PDE11A4 at serine 162). Altogether, these data suggest that a biologic designed to disrupt PDE11A4 homodimerization may serve to ameliorate age-related deficits in hippocampal cyclic nucleotide signaling and subsequent ARCD of remote social memory.

The sleep quality- and myopia-linked PDE11A-Y727C variant impacts neural physiology by reducing catalytic activity and altering subcellular compartmentalization of the enzyme

“…As previously described [1, 9], constructs were subcloned into a proprietary “SPW” lentivirus transfer vector by the University of South Carolina Viral Vector Core using the restriction sites described above. The “SPW” backbone drives expression using the phosphoglycerate kinase 1 (PGK) promoter and is preferentially taken up by neurons even though it is a ubiquitous promoter in theory [1, 9]. The lentiviruses delivered in 0.2M sucrose/42 mM NaCl/0.84 mM KCl/2.5 mM Na2HPO4/0.46 mM KH2PO4/0.35 mM EDTA and the original titers were as follows: WT at 4.86E+9 TU/mL, Y727C at 2.23E+09 TU/mL, and M878V at 6.69E+08 TU/mL.…”

“…As previously described [1, 9], HT22 cells were grown in Dulbecco’s Modified Eagle Medium (DMEM) with sodium pyruvate (GIBCO; Gaithersburg, MD) supplemented with 10% filtered Fetal Bovine Serum (R&D Systems, Bio-techne) and 1% Penicillin/Streptomycin (GE Healthcare Life Sciences; Logan, UT, USA). Cells were passaged in T-75 flasks and incubated at 37°C/5% CO 2 to reach 65-75% confluency.…”

“…PDE11A4 is strongly expressed in neurons of the ventral and dorsal hippocampus [4,5], the adjacent amygdalohippocampal and amygdalostriatal transition areas [1], the spinal cord and dorsal root ganglion [3], but not in any of the 20+ peripheral organs we have compared in young adult Pde11a KO versus WT mice to date [6]. Consistent with its particularly enriched expression in the ventral hippocampus, the best known neurological roles for PDE11A4 are regulating social interactions, altering the formation of social memories, impacting neuroinflammation, and triggering agerelated cognitive decline [1,4,5,[7][8][9][10][11][12].…”

“…Plasmid and lentivirus generation. As previously described [1,8,9], constructs were generated by Genscript (Piscataway, NJ) that expressed either EmGFP alone containing an A206Y mutation to prevent EmGFP dimerization [51], or an EmGFP-tagged mouse Pde11a4 (NM_001081033) with the BamHI and XhoI recognition sequences added to the N-terminal and C-terminal, respectively. These constructs were initially generated on a pUC57 backbone and then subcloned into a pcDNA3.1+ mammalian expression vector using the BamHI and XhoI sites (Life Technologies; Walthan, MA).…”

“…As previously described [1,9], constructs were subcloned into a proprietary "SPW" lentivirus transfer vector by the University of South Carolina Viral Vector Core using the restriction sites described above. The "SPW" backbone drives expression using the phosphoglycerate kinase 1 (PGK) promoter and is preferentially taken up by neurons even though it is a ubiquitous promoter in theory [1,9]. Ocular physiology studies.…”