Ping Liu

Terminal erythropoiesis requires dynamic membrane remodeling and trafficking, but the molecular regulation of these processes remains poorly understood. In this study, we identify GOLGA7, a predominantly Golgi-resident protein, as a regulator of CD71 clearance in reticulocytes and the erythropoietic response to hemolytic stress. Mice with hematopoietic-specific Golga7 deletion exhibited an increased proportion of CD71-positive circulating erythroid cells at steady state, while under hemolytic stress, they showed prolonged CD71 retention, delayed hematological recovery, and increased mortality. Multi-omic analyses of Golga7 deficient bone marrow erythroid cells revealed transcriptomic and proteomic alterations associated with vesicular trafficking. Functional assays showed that Golga7 deficiency delayed cell-surface CD71 clearance and prolonged intracellular transferrin retention without detectably affecting erythroid enucleation ex vivo. These findings highlight the contribution of GOLGA7 to terminal erythroid maturation and effective erythropoietic recovery under hemolytic stress.

Spermiogenesis, the final phrase of spermatogenesis, involves replacing histones by protamines, a process known as histone-to-protamine exchange, which is crucial for chromatin condensation. While this exchange is essential, the precise mechanisms remain incompletely understood. In this study, we discovered that the palmitoyltransferase ZDHHC19 functions as a key regulator of mouse spermiogenesis. Loss of Zdhhc19 leads to male infertility and abnormal sperm morphology. Zdhhc19 -deficient sperm exhibit impaired histone-to-protamine exchange, leading to retention of histones and misdistribution of protamines. Similarly, the palmitoyltransferase catalytic site mutant Zdhhc19 C142S knock-in mice show reduced fertility, sperm abnormalities, and histone retention. Mechanistically, ZDHHC19 mediates histone H3 palmitoylation at cysteine-110, weakening H3-H4 interactions and increasing chromatin accessibility. Palmitoylation of H3 facilitates histone-to-protamine exchange. This study highlights the essential role of ZDHHC19’s palmitoyl-transferase activity in histone-to-protamine exchange during spermiogenesis and underscores the broader role of histone palmitoylation in chromatin remodeling.

Hematopoietic stem cells (HSCs) are responsible for sustaining hematopoietic system throughout life, and their functional decline contributes to hematological disorders and organismal aging. Understanding the molecular mechanisms that govern HSC function is critical for developing interventions for treating and preventing aging-related diseases. Here, we show that DCAF8, a substrate recognition component of Cullin-RING E3 ubiquitin ligases, is highly expressed in HSCs and undergoes a progressive decline with age. Loss of DCAF8 in mice results in impaired function in HSCs, characterized by increased number yet decreased self-renewal capacity, which associates with cellular senescence and elevated DNA damage. Mechanistically, DCAF8 mediates the degradation of DOCK11, a guanine nucleotide exchange factor for CDC42. In the absence of DCAF8, DOCK11 accumulates, leading to elevated CDC42 activity and consequential loss of polarity of HSCs. Knocking out Dock11 mitigates the senescence, DNA damage, and self-renewal defects of Dcaf8-/- HSCs. This study highlights a critical role of DCAF8 in preventing HSC senescence via the DOCK11-CDC42 axis and suggests potential therapeutic targets for preventing functional decline in HSCs.

NRAS mutations are prevalent in human hematological malignancies and are also common in certain solid tumors, including melanoma and colon cancer. Despite their crucial role in oncogenesis, no effective therapies targeting NRAS have been developed. Inhibiting NRAS localization to the plasma membrane (PM) represents a promising strategy for cancer therapy, as its oncogenic signaling relies on PM localization. Knocking out Golgin subfamily A member 7 (Golga7), an accessory protein of RAS palmitoyltransferases, through a conditional gene editing approach drastically suppresses the development of myeloid leukemia induced by the activation of Nras^G12D/G12D knock‐in alleles in mice. The loss of Golga7 disrupts NRAS^G12D PM localization in bone marrow cells without altering the level of NRAS^G12D palmitoylation. Notably, Golga7 is dispensable for normal hematopoiesis in adult mice. While constitutive Golga7 knockout leads to embryonic lethality, the ubiquitous knockout of Golga7 induced in adult mice does not manifest any measurable toxic effects. These findings indicate that GOLGA7 is an effective and safe therapeutic target for NRAS‐driven leukemias.

Acute myeloid leukemia (AML) is an aging-related malignancy, with patients aged ≥60 years old facing significantly poorer prognosis. Umbilical cord blood (UCB) has emerged as a promising source with effective anti-aging roles. Here, we conducted a prospective, phase 2, single-arm trial of UCB infusion as an adjuvant consolidation therapy in elderly AML patients (ChiCTR-OPC-15006492). A total of 51 patients were enrolled (median age 66 years; range, 60–75) and received two cycles of consolidation chemotherapy combined with UCB infusion. At a median follow-up of 27.3 months (range, 9.3–100), the median overall survival (OS) was not yet reached and the median event-free survival (EFS) was 72.2 months (range, 5.4–100). The 2-year OS and EFS rates were 76.9% and 62.8%, respectively. No acute graft-versus-host disease (aGVHD) or toxicity-related death occurred in any patient. The median times to platelet and neutrophil recovery were 11.5 days (range, 6–17) and 12.2 days (range, 0–21), respectively. Single-cell RNA sequencing (scRNA-seq) identified enhanced anti-tumor and anti-aging properties of UCB, manifested through activation of immune responses and telomere synthesis/maintenance. These findings suggest that UCB infusion is an effective and safe post-remission adjuvant therapy for elderly AML patients. This study provides evidence that anti-aging therapy may serve as a new and promising dimension in combined cancer treatment.

Cyclin-dependent kinase 9 (CDK9) is a crucial component of transcription and potential target for anti-cancer therapies, particularly for hematological malignancies. However, the precise mechanisms underlying the therapeutic effects of CDK9 inhibitors remain not fully understood. Here, we found that inhibiting CDK9 either pharmacologically or through gene downregulation, significantly reduced the levels of α-tubulin protein in a time- and dose-dependent manner. We further discovered that CDK9 inhibition led to increased susceptibility of α-tubulin to proteasomal degradation due to reduced acetylation at lysine 40 (K40), an important modification for microtubule stability. An acetylation-mimicking mutant of α-tubulin mitigated the anti-tumor effects of CDK9 inhibition. Mechanically, we identified that CDK9 inhibition downregulated the expression of ATAT1, the acetyltransferase responsible for α-tubulin acetylation, further compromising microtubule stability. We also conducted in vivo studies in a leukemic xenograft model, where AZD4573 treatment led to significant tumor regression, decreased ATAT1 expression, and α-tubulin degradation. Our study unravels a novel molecular mechanism by which CDK9 inhibition disrupts α-tubulin stability and provides valuable insights for exploring effective treatment regimens involving CDK9 inhibitors.