Acetaminophen overdose is the leading cause of acute liver failure, with one available treatment, NAC. Yet, NAC effectiveness diminishes about ten hours after APAP overdose, urging for therapeutic alternatives. Promoting intrinsic liver regeneration could address this unmet need by temporally activating key hepatocyte regenerative pathways in order to accelerate recovery from acute APAP-induced liver injury. In aim 1, we established an efficient, safe, non-integrative method to transiently express HGF and EGF in hepatocytes via nucleoside-modified mRNA-LNP delivery in mice. We confirmed specific hepatotropism of mRNA-LNP via intravenous injection of firefly luciferase encoding mRNA-LNP, with protein expression lasting about 3 days. In the liver, virtually all hepatocytes were transfected along with a subpopulation of endothelial and Kupffer cells. In homeostasis, HGF mRNA-LNP efficiently induced hepatocyte proliferation. In a chronic liver injury mouse model recapitulating nonalcoholic fatty liver disease, injections of both HGF and EGF mRNA-LNP sharply reversed steatosis and accelerated restoration of liver function. Likewise, HGF and EGF mRNA-LNP accelerated liver regeneration after APAP-induced acute liver injury with rapid return to baseline of levels of serum liver injury markers such as ALT. This study introduced mRNA-LNP as a potentially translatable safe therapeutic intervention to harness liver regeneration via controlled expression of endogenous mitogens in vivo.
In aim 2, we characterized the sexually differential injury induced between males and females following APAP overdose. Consistent with the literature, our data showed higher resistance of female mice to APAP, shown by reduced liver necrosis, cell death, and detection of serum injury markers compared to males. Moreover, our single-cell RNA sequencing analyses revealed that female hepatocytes and endothelial cells express significantly higher levels of GH receptor and GH pathway activation than male cells, while males have upregulated inflammatory and cell death pathway activation.
Therefore, in aim 3, we took advantage of the greater resistance of female mice and greater activation of the GH pathway to evaluate a novel treatment for APAP-induced acute liver injury utilizing growth hormone. Sex hormones and their receptors have been implicated in driving sexual dimorphism in many liver processes. Specifically, pituitary GH secretory patterns, pulsatile in males and near-continuous in females, determine the sex bias in many liver metabolic functions. In harnessing this female-specific advantage, we demonstrated that injection of recombinant human GH protein in APAP-injured mice accelerates liver recovery, promotes survival, and is superior to standard-of-care NAC. Delivery of slow-released human GH mRNA-LNP also rescues males from APAP-induced death that otherwise occurred in control mRNA-LNP-treated mice.
In conclusion, this study demonstrates a sexually dimorphic liver repair advantage in females following APAP overdose, leveraged by establishing GH as an alternative treatment, delivered either as recombinant protein or mRNA-LNP, to potentially prevent liver failure and liver transplant in APAP-overdosed patients. / 2025-11-02T00:00:00Z
| Identifer | oai:union.ndltd.org:bu.edu/oai:open.bu.edu:2144/47415 |
| Date | 02 November 2023 |
| Creators | Everton, Elissa |
| Contributors | Gouon-Evans, Valerie |
| Source Sets | Boston University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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