Renal Repair Mechanisms in Acute Kidney Injury

Acute kidney injury (AKI) arises from a sudden loss of renal function, often triggered by ischaemia, toxins or inflammation, and carries substantial risk of progression to chronic kidney disease. Recovery depends on a finely balanced interplay between adaptive repair—where surviving tubular epithelial cells enlarge via endocycle-driven hypertrophy and a minority of resident progenitor cells proliferates to replace lost nephrons—and maladaptive repair, which is marked by persistent inflammation, failed tubular regeneration and interstitial fibrosis. Key influences on this balance include metabolic reprogramming of proximal tubule cells, epigenetic regulation of repair programmes, and the emergence of distinct pro-inflammatory epithelial states. Advances in single-cell and multiomic technologies are now illuminating the transcriptional and chromatin landscapes that underlie successful regeneration versus fibrotic remodelling, offering new targets to steer repair towards restoration of function.

Research from Nature Portfolio

Recent studies have applied single-nucleus multiomic sequencing to map the transition from healthy to failed repair in human proximal tubule cells, constructing gene regulatory networks that pinpoint critical drivers of maladaptive states. This approach identified NFAT5 as a master regulator of profibrotic and pro-inflammatory programmes, opening avenues for targeted modulation of tubular fate. Complementary single-cell transcriptomic analyses in rodent models have contrasted adaptive versus fibrotic repair trajectories by profiling over 110 000 cells across time points after ischaemic injury. These data delineate a specific maladaptive proximal tubule cluster expressing cytokines and chemotactic factors, and reveal that pharmacological inhibition of pyroptosis and ferroptosis pathways can shift the balance towards functional recovery and attenuate fibrosis. Foundational work has further shown that endocycle-mediated hypertrophy of surviving tubular cells, together with the clonal expansion of Pax2+ progenitors, underpins the bulk of nephron restoration following AKI.

Renal Repair Mechanisms in Acute Kidney Injury publication trend

The graph below shows the total number of articles in renal repair mechanisms in acute kidney injury across all publications each year (not limited to Nature Index journals).

Technical terms

Proximal tubule: The segment of the nephron responsible for the bulk of solute and fluid reabsorption, highly susceptible to ischaemic and toxic injury.

Endocycle: A modified cell cycle in which DNA replication occurs without cell division, leading to cellular hypertrophy and increased functional capacity.

Progenitor cell: A less-differentiated epithelial cell capable of limited self-renewal and replacement of specialised cells during repair.

Pyroptosis: A form of programmed cell death characterised by inflammasome activation and release of pro-inflammatory cytokines.

Ferroptosis: An iron-dependent, lipid peroxidation-driven cell death pathway implicated in maladaptive inflammatory responses.

Fibrosis: Excessive deposition of extracellular matrix in the interstitium, leading to organ stiffening and impaired function.

References

1. Predicting proximal tubule failed repair drivers through regularized regression analysis of single cell multiomic sequencing. Nature Communications (2024).
2. WT1+ glomerular parietal epithelial progenitors promote renal proximal tubule regeneration after severe acute kidney injury. Theranostics (2023).
3. FAM3A plays a key role in protecting against tubular cell pyroptosis and acute kidney injury. Redox Biology (2024).
4. Endocycle-related tubular cell hypertrophy and progenitor proliferation recover renal function after acute kidney injury. Nature Communications (2018).
5. Ferroptotic stress promotes the accumulation of pro-inflammatory proximal tubular cells in maladaptive renal repair. eLife (2021).
6. Single-cell analysis highlights differences in druggable pathways underlying adaptive or fibrotic kidney regeneration. Nature Communications (2022).