ALDH1A3 Is the Key Isoform That Contributes to Aldehyde Dehydrogenase Activity and Affects in Vitro Proliferation in Cardiac Atrial Appendage Progenitor Cells
Bibliographic record
Abstract
High aldehyde dehydrogenase (ALDHhi) activity has been reported in normal and cancer stem cells. We and others have shown previously that human ALDHhi cardiac atrial appendage cells are enriched with stem/progenitor cells. The role of ALDH in these cells is poorly understood but it may come down to the specific ALDH isoform(s) expressed. This study aimed to compare ALDHhi and ALDHlo atrial cells and to identify the isoform(s) that contribute to ALDH activity, and their functional role. Methods and Results: Cells were isolated from atrial appendage specimens from patients with ischemic and/or valvular heart disease undergoing heart surgery. ALDHhi activity assessed with the Aldefluor reagent coincided with primitive surface marker expression (CD34+). Depending on their ALDH activity, RT-PCR analysis of ALDHhi and ALDHlo cells demonstrated a differential pattern of pluripotency genes (Oct4, Nanog) and genes for more established cardiac lineages (Nkx2.5, Tbx5, Mef2c, GATA4). ALDHhi cells, but not ALDHlo cells, formed clones and were culture-expanded. When cultured under cardiac differentiation conditions, ALDHhi cells gave rise to a higher number of cardiomyocytes compared with ALDHlo cells. Among 19 ALDH isoforms known in human, ALDH1A3 was most highly expressed in ALDHhi atrial cells. Knocking down ALDH1A3, but not ALDH1A1, ALDH1A2, ALDH2, ALDH4A1 or ALDH8A1 using siRNA decreased ALDH activity and cell proliferation in ALDHhi cells. Conversely, overexpressing ALDH1A3 with a retroviral vector increased proliferation in ALDHlo cells. Conclusions: ALDH1A3 is the key isoform responsible for ALDH activity in ALDHhi atrial appendage cells, which have a propensity to differentiate into cardiomyocytes. ALDH1A3 affects in vitro proliferation of these cells.
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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) | 0.000 | 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 | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".