MP053INCREASED OR REDUCED PODOCYTE ZHX2 EXPRESSION EXACERBATES FOCAL SEGMENTAL GLOMERULOSCLEROSIS
Bibliographic record
Abstract
INTRODUCTION AND AIMS: Zinc fingers and homeoboxes (ZHX) transcriptional factor family members, major regulators of podocyte gene expression, are tethered to the cell membrane as heterodimers and homodimers. ZHX2-ZHX1 heterodimers are mostly present in the podocyte body, and ZHX2-ZHX3 at the slit diaphragm. Changes in overall ZHX2 expression leads to loss of heterodimerization, that promotes nuclear entry and changes in gene expression. METHODS: To study loss of heterodimerization due to ZHX2 overexpression, podocyte-specific ZHX2 transgenic rats were generated using the human NPHS2 promoter. Following baseline characterization, we induced Adriamycin nephrosis (ADR), a model of focal segmental glomerulosclerosis (FSGS). Also, ZHX2 transgenic rats were backcrossed 10 generations into the Buffalo/Mna background, another model of FSGS. To study loss of heterodimerization due to low ZHX2 expression, Balbc/J mice, that are naturally Zhx2 deficient, were injected with ADR. We also stained human FSGS biopsies for ZHX proteins. RESULTS: Confocal characterization of ZHX2 protein expression in human kidney biopsies from FSGS patients revealed either increase or decrease in overall expression of ZHX2, often with major redistribution of ZHX2 and/or ZHX3 to the podocyte nucleus. Balb/cJ mice (low ZHX2 content) has lower baseline albuminuria levels compared with Balb/c (normal ZHX2 content). When treated with ADR, Balbc/cJ mice developed higher albuminuria levels at day 14 after treatment (873.53 ± 413.46 µg per 18 h) compare with Balb/c (65.64 ± 18.91 µg per 18 h) (p<0.05) To study the effect of ZHX2 overexpression, three founder lines of ZHX2 podocyte-specific transgenic rats were characterized (TG 14, TG 142 and TG 144). Glomerular mRNA expression of ZHX2 in heterozygous transgenic rats showed an increase, compared to WT littermates, of 1.13 ± 0.10 in TG 14, 1.50 ± 0.09 in TG 142 and 4.09 ± 0.69 in TG 144. Baseline confocal characterization of glomeruli in heterozygous TG 144 rats revealed increased expression of ZHX2 in a podocyte cell membrane distribution. Overall expression of ZHX3 and ZHX1 was unchanged. None of the ZHX2 transgenic rat lines had proteinuria at baseline. When compared with WT littermates, proteinuria and renal histology on Day 7 of Adriamycin nephrosis was most severe in TG 144 (310.4 ± 41.5 mg per 18 h; p<0.01) and was associated with higher mortality, and also more severe in TG 142 (204.8 ± 29.95 mg per 18 h; p<0.01) than control (102.6 ± 19.5 mg per 18 h) or TG 14 (89.1 ±31.95 mg per 18 h; indistinguishable from control). Backcross of the ZHX2 transgene into the Buff/Mna rat background for 10 generations was associated with more proteinuria at age 8 months (301.9 ± 27.4 mg per 18 h) than the Buff/Mna (193.8 ±23.7 mg per 18 h) (p<0.05). CONCLUSIONS: Loss of heterodimerization caused by overexpression or deficiency of ZHX2 in podocytes worsens the development of FSGS. These findings suggest the importance of optimal ZHX2 expression levels in avoiding relapse or worsening of FSGS.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".