Inflammatory Cytokine TNFα Promotes the Long-Term Expansion of Primary Hepatocytes in 3D Culture.

In the healthy adult liver, most hepatocytes proliferate minimally. However, upon physical or chemical injury to the liver, hepatocytes proliferate extensively in vivo under the direction of multiple extracellular cues, including Wnt and pro-inflammatory signals. Currently, liver organoids can be generated readily in vitro from bile-duct epithelial cells, but not hepatocytes. Here, we show that TNFα, an injury-induced inflammatory cytokine, promotes the expansion of hepatocytes in 3D culture and enables serial passaging and long-term culture for more than 6 months. Single-cell RNA sequencing reveals broad expression of hepatocyte markers. Strikingly, in vitro-expanded hepatocytes engrafted, and significantly repopulated, the injured livers of Fah-/- mice. We anticipate that tissue repair signals can be harnessed to promote the expansion of otherwise hard-to-culture cell-types, with broad implications.

AGA Clinical Practice Update on Diagnosis and Management of Acute Hepatic Porphyrias: Expert Review.

DESCRIPTION: The acute hepatic porphyrias (AHP) are rare, inborn errors of heme-metabolism and include acute intermittent porphyria, hereditary coproporphyria, variegate porphyria, and porphyria due to severe deficiency of 5-aminolevulinic acid dehydratase. Acute intermittent porphyria is the most common type of AHP, with an estimated prevalence of patients with symptoms of approximately 1 in 100,000. The major clinical presentation involves attacks of severe pain, usually abdominal and generalized, without peritoneal signs or abnormalities on cross-sectional imaging. Acute attacks occur mainly in women in their childbearing years. AHP should be considered in the evaluation of all patients, and especially women aged 15-50 years with recurrent severe abdominal pain not ascribable to common causes. The screening tests of choice include random urine porphobilinogen and δ-aminolevulinic acid corrected to creatinine. All patients with elevations in urinary porphobilinogen and/or δ-aminolevulinic acid should initially be presumed to have AHP. The cornerstones of management include discontinuation of porphyrinogenic drugs and chemicals, administration of oral or intravenous dextrose and intravenous hemin, and use of analgesics and antiemetics. Diagnosis of AHP type can be confirmed after initial treatment by genetic testing for pathogenic variants in HMBS, CPOX, PPOX, and ALAD genes. AHP is also associated with chronic symptoms and long-term risk of systemic arterial hypertension, chronic renal and liver disease, and hepatocellular carcinoma. Patients who have recurrent acute attacks (4 or more per year) should be considered for prophylactic therapy with intravenous hemin or subcutaneous givosiran. Liver transplantation is curative and reserved for patients with intractable symptoms who have failed other treatment options. METHODS: This expert review was commissioned and approved by the American Gastroenterological Association (AGA) Institute Clinical Practice Updates Committee (CPUC) and the AGA Governing Board to provide timely guidance on a topic of high clinical importance to the AGA membership, and underwent internal peer review by the CPUC and external peer review through standard procedures of Gastroenterology. These Best Practice Advice (BPA) statements were drawn from a review of the published literature and from expert opinion. Because systematic reviews were not performed, these BPA statements do not carry formal ratings of the quality of evidence or strength of the presented considerations. Best Practice Advice Statements BEST PRACTICE ADVICE 1: Women aged 15-50 years with unexplained, recurrent severe abdominal pain without a clear etiology after an initial workup should be considered for screening for an AHP. BEST PRACTICE ADVICE 2: Initial diagnosis of AHP should be made by biochemical testing measuring δ-aminolevulinic acid, porphobilinogen, and creatinine on a random urine sample. BEST PRACTICE ADVICE 3: Genetic testing should be used to confirm the diagnosis of AHP in patients with positive biochemical testing. BEST PRACTICE ADVICE 4: Acute attacks of AHP that are severe enough to require hospital admission should be treated with intravenous hemin, given daily, preferably into a high-flow central vein. BEST PRACTICE ADVICE 5: In addition to intravenous hemin, management of acute attacks of AHP should include pain control, antiemetics, management of systemic arterial hypertension, tachycardia, and hyponatremia, and hypomagnesemia, if present. BEST PRACTICE ADVICE 6: Patients should be counseled to avoid identifiable triggers that may precipitate acute attacks, such as alcohol and porphyrinogenic medications. BEST PRACTICE ADVICE 7: Prophylactic heme therapy or givosiran, administered in an outpatient setting, should be considered in patients with recurrent attacks (4 or more per year). BEST PRACTICE ADVICE 8: Liver transplantation for AHP should be limited to patients with intractable symptoms and significantly decreased quality of life who are refractory to pharmacotherapy. BEST PRACTICE ADVICE 9: Patients with AHP should be monitored annually for liver disease. BEST PRACTICE ADVICE 10: Patients with AHP, regardless of the severity of symptoms, should undergo surveillance for hepatocellular carcinoma, beginning at age 50 years, with liver ultrasound every 6 months. BEST PRACTICE ADVICE 11: Patients with AHP on treatment should undergo surveillance for chronic kidney disease annually with serum creatinine and estimated glomerular filtration rate. BEST PRACTICE ADVICE 12: Patients should be counseled on the chronic and long-term complications of AHP, including neuropathy, chronic kidney disease, hypertension, and hepatocellular carcinoma, and need for long-term monitoring.

Liver transplantation and primary liver cancer in porphyria.

The porphyrias are a heterogeneous group of metabolic disorders that result from defects in heme synthesis. The metabolic defects are present in all cells, but symptoms are mainly cutaneous or related to neuropathy. The porphyrias are highly relevant to hepatologists since patients can present with symptoms and complications that require liver transplantation (LT), and some porphyrias are associated with a high risk for primary liver cancer (PLC). Among the cutaneous porphyrias, erythropoietic protoporphyria (EPP) can lead to cholestatic liver failure where LT cures the liver disease but not the porphyria. In acute porphyria (AP), neurotoxic porphyrin precursors are produced in the liver and LT is a curative treatment option in patients with recurrent severe neuropathic attacks. Patients with AP, mainly acute intermittent porphyria, have a significantly increased risk for PLC that warrants surveillance and adequate follow-up of high-risk groups. LT is well established in both EPP with liver failure and AP with recurrent attacks, but most transplant centres have little porphyria experience and cooperation between transplant hepatologists, and porphyria experts is important in the often-difficult decisions on timing and management of comorbid conditions.

The epidemiology, treatments and outcomes of patients with hormone receptor positive, human epidermal growth factor receptor 2 negative, node-positive early breast cancer in Taiwan.

Aim: Estimate patient counts, treatment patterns and outcomes of a subset of patients with early breast cancer (EBC) presenting with hormone receptor positive, human epidermal growth factor receptor 2 negative, node positive features, who are at high-risk of recurrence, in Taiwan.Materials & methods: Data from Taiwan's National Health Insurance Research Database and Taiwan Cancer Registry from 1 January 2011 to 31 December 2020 were analyzed.Results: There were 4500 patients with high-risk EBC (10.4% of all patients with EBC) from 2012 to 2018, with an annual average incidence of 643 that increased over time. Five-year progression was 24.8% in patients with high-risk EBC and 8-year survival was low (69.6%).Conclusion: Patients with hormone receptor positive, human epidermal growth factor receptor 2 negative, node positive high-risk EBC clinical features are an increasing high-risk subset of all patients with EBC.

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Hierarchical transitions and fractal wrinkling drive bacterial pellicle morphogenesis.

Bacterial cells can self-organize into structured communities at fluid-fluid interfaces. These soft, living materials composed of cells and extracellular matrix are called pellicles. Cells residing in pellicles garner group-level survival advantages such as increased antibiotic resistance. The dynamics of pellicle formation and, more generally, how complex morphologies arise from active biomaterials confined at interfaces are not well understood. Here, using Vibrio cholerae as our model organism, a custom-built adaptive stereo microscope, fluorescence imaging, mechanical theory, and simulations, we report a fractal wrinkling morphogenesis program that differs radically from the well-known coalescence of wrinkles into folds that occurs in passive thin films at fluid-fluid interfaces. Four stages occur: growth of founding colonies, onset of primary wrinkles, development of secondary curved ridge instabilities, and finally the emergence of a cascade of finer structures with fractal-like scaling in wavelength. The time evolution of pellicle formation depends on the initial heterogeneity of the film microstructure. Changing the starting bacterial seeding density produces three variations in the sequence of morphogenic stages, which we term the bypass, crystalline, and incomplete modes. Despite these global architectural transitions, individual microcolonies remain spatially segregated, and thus, the community maintains spatial and genetic heterogeneity. Our results suggest that the memory of the original microstructure is critical in setting the morphogenic dynamics of a pellicle as an active biomaterial.

Phase 3 Trial of RNAi Therapeutic Givosiran for Acute Intermittent Porphyria.

BACKGROUND: Up-regulation of hepatic delta-aminolevulinic acid synthase 1 (ALAS1), with resultant accumulation of delta-aminolevulinic acid (ALA) and porphobilinogen, is central to the pathogenesis of acute attacks and chronic symptoms in acute hepatic porphyria. Givosiran, an RNA interference therapy, inhibits ALAS1 expression. METHODS: In this double-blind, placebo-controlled, phase 3 trial, we randomly assigned symptomatic patients with acute hepatic porphyria to receive either subcutaneous givosiran (2.5 mg per kilogram of body weight) or placebo monthly for 6 months. The primary end point was the annualized rate of composite porphyria attacks among patients with acute intermittent porphyria, the most common subtype of acute hepatic porphyria. (Composite porphyria attacks resulted in hospitalization, an urgent health care visit, or intravenous administration of hemin at home.) Key secondary end points were levels of ALA and porphobilinogen and the annualized attack rate among patients with acute hepatic porphyria, along with hemin use and daily worst pain scores in patients with acute intermittent porphyria. RESULTS: A total of 94 patients underwent randomization (48 in the givosiran group and 46 in the placebo group). Among the 89 patients with acute intermittent porphyria, the mean annualized attack rate was 3.2 in the givosiran group and 12.5 in the placebo group, representing a 74% lower rate in the givosiran group (P<0.001); the results were similar among the 94 patients with acute hepatic porphyria. Among the patients with acute intermittent porphyria, givosiran led to lower levels of urinary ALA and porphobilinogen, fewer days of hemin use, and better daily scores for pain than placebo. Key adverse events that were observed more frequently in the givosiran group were elevations in serum aminotransferase levels, changes in serum creatinine levels and the estimated glomerular filtration rate, and injection-site reactions. CONCLUSIONS: Among patients with acute intermittent porphyria, those who received givosiran had a significantly lower rate of porphyria attacks and better results for multiple other disease manifestations than those who received placebo. The increased efficacy was accompanied by a higher frequency of hepatic and renal adverse events. (Funded by Alnylam Pharmaceuticals; ENVISION ClinicalTrials.gov number, NCT03338816.).

Rare, Overlooked, or Underappreciated Causes of Recurrent Abdominal Pain: A Primer for Gastroenterologists.

Recurrent abdominal pain is a common reason for repeated visits to outpatient clinics and emergency departments, reflecting a substantial unmet need for timely and accurate diagnosis. A lack of awareness of some of the rarer causes of recurrent abdominal pain may impede diagnosis and delay effective management. This article identifies some of the key rare but diagnosable causes that are frequently missed by gastroenterologists and provides expert recommendations to support recognition, diagnosis, and management with the ultimate aim of improving patient outcomes.

Evidence-based consensus guidelines for the diagnosis and management of erythropoietic protoporphyria and X-linked protoporphyria.

Erythropoietic protoporphyria and X-linked protoporphyria are rare genetic photodermatoses. Limited expertise with these disorders among physicians leads to diagnostic delays. Here, we present evidence-based consensus guidelines for the diagnosis, monitoring, and management of erythropoietic protoporphyria and X-linked protoporphyria. A systematic literature review was conducted, and reviewed among subcommittees of experts, divided by topic. Consensus on guidelines was reached within each subcommittee and then among all members of the committee. The appropriate biochemical and genetic testing to establish the diagnosis is reviewed in addition to the interpretation of results. Prevention of symptoms, management of acute phototoxicity, and pharmacologic and nonpharmacologic treatment options are discussed. The importance of ongoing monitoring for liver disease, iron deficiency, and vitamin D deficiency is discussed with management guidance. Finally, management of pregnancy and surgery and the safety of other therapies are summarized. We emphasize that these are multisystemic disorders that require longitudinal monitoring. These guidelines provide a structure for evidence-based diagnosis and management for practicing physicians. Early diagnosis and management of these disorders are essential, particularly given the availability of new and emerging therapies.

Hepatocellular Carcinoma in Acute Hepatic Porphyrias: Results from the Longitudinal Study of the U.S. Porphyrias Consortium.

BACKGROUND AND AIMS: The risk for hepatocellular carcinoma (HCC) is increased in acute hepatic porphyrias (AHP). The aim of this study was to explore the clinicopathologic characteristics, outcomes, and frequency of HCC in patients with AHP in the United States. APPROACH AND RESULTS: This cross-sectional analysis evaluated patients with HCC in a multicenter, longitudinal study of AHP. Among 327 patients with AHP, 5 (1.5%) were diagnosed with HCC. Of the 5 HCC cases, 4 had acute intermittent porphyria and 1 had variegate porphyria, confirmed by biochemical and/or genetic testing. All patients were white females, with a median age of 27 years (range 21-75) at diagnosis. The median age at HCC diagnosis was 69 years (range 61-74). AHP was asymptomatic in 2 patients; 2 reported sporadic attacks; and 1 reported recurrent attacks (>4 attacks/year). All patients had a single HCC lesion on liver imaging that was 1.8-6.5 centimeters in diameter. Serum alpha fetoprotein levels were below 10 ng/mL in all 4 patients with available results. Four patients underwent liver resection, and 1 was treated with radioembolization. No significant inflammation or fibrosis was found in adjacent liver tissues of 3 patients who underwent liver resection. Two patients developed recurrence of HCC at 22 and 26 months following liver resection. All patients are alive with survival times from HCC diagnosis ranging from 26-153 months. CONCLUSION: In this U.S. study, 1.5% of patients with AHP had HCC. HCC in AHP occurred in the absence of cirrhosis, which contrasts with other chronic liver diseases. Patients with AHP, regardless of clinical attacks, should be screened for HCC, beginning at age 50. The pathogenesis of hepatocarcinogenesis in AHP is unknown and needs further investigation.

TBX3 functions as a tumor suppressor downstream of activated CTNNB1 mutants during hepatocarcinogenesis.

BACKGROUND & AIMS: Gain of function (GOF) mutations in the CTNNB1 gene are one of the most frequent genetic events in hepatocellular carcinoma (HCC). T-box transcription factor 3 (TBX3) is a liver-specific target of the Wnt/ß-catenin pathway and thought to be an oncogene mediating activated ß-catenin-driven HCC formation. METHODS: We evaluated the expression pattern of TBX3 in human HCC specimens. Tbx3 was conditionally knocked out in murine HCC models by hydrodynamic tail vein injection of Cre together with c-Met and ΔN90-ß-catenin (c-Met/ß-catenin) in Tbx3flox/flox mice. TBX3 was overexpressed in human HCC cell lines to investigate the functions of TBX3 in vitro. RESULTS: A bimodal expression pattern of TBX3 in human HCC samples was detected: high expression of TBX3 in GOF CTNNB1 HCC and downregulation of TBX3 in non-CTNNB1 mutant tumors. High expression of TBX3 was associated with increased differentiation and decreased expression signatures of tumor growth. Using Tbx3flox/flox mice, we found that ablation of Tbx3 significantly accelerates c-Met/ß-catenin-driven HCC formation. Moreover, Tbx3(-) HCC demonstrated increased YAP/TAZ activity. The accelerated tumor growth induced by loss of TBX3 in c-Met/ß-catenin mouse HCC was successfully prevented by overexpression of LATS2, which inhibited YAP/TAZ activity. In human HCC cell lines, overexpression of TBX3 inhibited HCC cell growth as well as YAP/TAZ activation. A negative correlation between TBX3 and YAP/TAZ target genes was observed in human HCC samples. Mechanistically, phospholipase D1 (PLD1), a known positive regulator of YAP/TAZ, was identified as a novel transcriptional target repressed by TBX3. CONCLUSION: Our study suggests that TBX3 is induced by GOF CTNNB1 mutants and suppresses HCC growth by inactivating PLD1, thus leading to the inhibition of YAP/TAZ oncogenes. LAY SUMMARY: TBX3 is a liver-specific target of the Wnt/ß-catenin pathway and thought to be an oncogene in promoting liver cancer development. Herein, we demonstrate that TBX3 is in fact a tumor suppressor gene that restricts liver tumor growth. Strategies which increase TBX3 expression and/or activities may be effective for HCC treatment.

Evidence in the UK Biobank for the underdiagnosis of erythropoietic protoporphyria.

PURPOSE: Erythropoietic protoporphyria (EPP), characterized by painful cutaneous photosensitivity, results from pathogenic variants in ferrochelatase (FECH). For 96% of patients, EPP results from coinheriting a rare pathogenic variant in trans of a common hypomorphic variant c.315-48T>C (minor allele frequency 0.05). The estimated prevalence of EPP derived from the number of diagnosed individuals in Europe is 0.00092%, but this may be conservative due to underdiagnosis. No study has estimated EPP prevalence using large genetic data sets. METHODS: Disease-associated FECH variants were identified in the UK Biobank, a data set of 500,953 individuals including 49,960 exome sequences. EPP prevalence was then estimated. The association of FECH variants with EPP-related traits was assessed. RESULTS: Analysis of pathogenic FECH variants in the UK Biobank provides evidence that EPP prevalence is 0.0059% (95% confidence interval [CI]: 0.0042-0.0076%), 1.7-3.0 times more common than previously thought in the UK. In homozygotes for the common c.315-48T>C FECH variant, there was a novel decrement in both erythrocyte mean corpuscular volume (MCV) and hemoglobin. CONCLUSION: The prevalence of EPP has been underestimated secondary to underdiagnosis. The common c.315-48T>C allele is associated with both MCV and hemoglobin, an association that could be important both for those with and without EPP.

mTORC2 Signaling Is Necessary for Timely Liver Regeneration after Partial Hepatectomy.

Liver regeneration is a fundamental biological process required for sustaining body homeostasis and restoring liver function after injury. Emerging evidence demonstrates that cytokines, growth factors, and multiple signaling pathways contribute to liver regeneration. Mammalian target of rapamycin complex 2 (mTORC2) regulates cell metabolism, proliferation and survival. The major substrates for mTORC2 are the AGC family members of kinases, including AKT, SGK, and PKC-α. We investigated the functional roles of mTORC2 during liver regeneration. Partial hepatectomy (PHx) was performed in liver-specific Rictor (the pivotal unit of mTORC2 complex) knockout (RictorLKO) and wild-type (Rictorfl/fl) mice. Rictor-deficient mice were found to be more intolerant to PHx and displayed higher mortality after PHx. Mechanistically, loss of Rictor resulted in decreased Akt phosphorylation, leading to a delay in hepatocyte proliferation and lipid droplets formation along liver regeneration. Overall, these results indicate an essential role of the mTORC2 signaling pathway during liver regeneration.

Novel treatment options for acute hepatic porphyrias.

PURPOSE OF REVIEW: Acute hepatic porphyrias (AHP) are a group of rare diseases that are characterized by episodic acute neurovisceral pain episodes caused by abnormal accumulation of the neurotoxic porphyrin precursor delta-aminolevulinic acid (ALA). Patient with frequent recurrent acute attacks have been difficult to treat and these patients sometimes require liver transplantation. Recent developments in small interfering RNA (siRNA)-based therapy led to the development of an effective prophylactic treatment for patients with frequent recurrent attacks. This review will describe treatment options for AHP and highlight management in light of new treatment option. RECENT FINDINGS: Givosiran is a novel siRNA-based therapy targeted specifically to hepatocytes to inhibit ALA synthase 1, the first and rate-limiting step in heme biosynthesis. Patients with frequent recurrent attacks treated with givosiran had durable normalization of ALA and significantly reduced numbers of acute attacks and need for hemin treatment. The overall safety profile for givosiran was comparable with placebo and the drug was recently approved by the Food and Drug Administration for treatment of AHP patients. SUMMARY: Givosiran is an effective treatment for prevention of acute porphyria attacks in AHP patients with frequent recurrent attacks.

Relationship between transfusion burden, healthcare resource utilization, and complications in patients with beta-thalassemia in Taiwan: A real-world analysis.

BACKGROUND: This study utilized a population-based claims database to identify patients with beta-thalassemia and evaluate associations between transfusion burden, healthcare resource utilization (HCRU), and complications. STUDY DESIGN AND METHODS: Taiwan's National Health Insurance Research Database was used to identify patients with beta-thalassemia (ICD-10 D56.1) in 2016. Patients with a beta-thalassemia claim in 2016 were indexed into the study at their first claim on or after January 1, 2001 in the dataset through to December 31, 2016 and followed until the end of study. During the follow-up period, red blood cell transfusion (RBCT) units, HCRU, iron chelation therapy use, and beta-thalassemia-related complications incidence were recorded. Patients were grouped into transfusion burden severity cohorts based on average number of RBCT units per 12 weeks during follow-up: 0 RBCT units, >0 to <6 RBCT units (mild), ≥6 to <12 RBCT units (moderate), and ≥12 RBCT units (severe). RESULTS: A total of 2984 patients were included with mean follow-up of 6.95 years. Of these, 1616 (54.2%) patients had no claims for RBCT units, 1112 (37.3%) had claims for >0 to <6 RBCT units, 112 (3.8%) for ≥6 to <12 RBCT units, and 144 (4.8%) for ≥12 RBCT units per 12 weeks. Transfused patients had significantly more all-cause HCRU and iron chelation therapy compared with non-transfused patients during follow-up. Thalassemia-related HCRU and risk of liver, endocrine, cardiac, and renal complications were significantly and positively correlated with increases of RBCT units. DISCUSSION: Clinical and healthcare resource burden of patients with beta-thalassemia is closely related to transfusion burden.

Self-renewing diploid Axin2(+) cells fuel homeostatic renewal of the liver.

The source of new hepatocytes in the uninjured liver has remained an open question. By lineage tracing using the Wnt-responsive gene Axin2 in mice, we identify a population of proliferating and self-renewing cells adjacent to the central vein in the liver lobule. These pericentral cells express the early liver progenitor marker Tbx3, are diploid, and thereby differ from mature hepatocytes, which are mostly polyploid. The descendants of pericentral cells differentiate into Tbx3-negative, polyploid hepatocytes, and can replace all hepatocytes along the liver lobule during homeostatic renewal. Adjacent central vein endothelial cells provide Wnt signals that maintain the pericentral cells, thereby constituting the niche. Thus, we identify a cell population in the liver that subserves homeostatic hepatocyte renewal, characterize its anatomical niche, and identify molecular signals that regulate its activity.

Evaluating the Patient-Reported Outcomes Measurement Information System scales in acute intermittent porphyria.

PURPOSE: Acute intermittent porphyria (AIP) is a rare inborn error of heme biosynthesis characterized by life-threatening acute attacks. Few studies have assessed quality of life (QoL) in AIP and those that have had small sample sizes and used tools that may not have captured important domains. METHODS: Baseline data from the Porphyrias Consortium's Longitudinal Study were obtained for 259 patients, including detailed disease and medical history data, and the following Patient-Reported Outcomes Measurement Information System (PROMIS) scales: anxiety, depression, pain interference, fatigue, sleep disturbance, physical function, and satisfaction with social roles. Relationships between PROMIS scores and clinical and biochemical AIP features were explored. RESULTS: PROMIS scores were significantly worse than the general population across all domains, except depression. Each domain discriminated well between asymptomatic and symptomatic patients with symptomatic patients having worse scores. Many important clinical variables like symptom frequency were significantly associated with domain scores in univariate analyses, showing responsiveness of the scales, specifically pain interference and fatigue. However, most regression models only explained ~20% of the variability observed in domain scores. CONCLUSION: Pain interference and fatigue were the most responsive scales in measuring QoL in this AIP cohort. Future studies should assess whether these scales capture longitudinal disease progression and treatment response.

Tissue Repair in the Mouse Liver Following Acute Carbon Tetrachloride Depends on Injury-Induced Wnt/ß-Catenin Signaling.

In the liver, Wnt/ß-catenin signaling is involved in regulating zonation and hepatocyte proliferation during homeostasis. We examined Wnt gene expression and signaling after injury, and we show by in situ hybridization that Wnts are activated by acute carbon tetrachloride (CCl4 ) toxicity. Following injury, peri-injury hepatocytes become Wnt-responsive, expressing the Wnt target gene axis inhibition protein 2 (Axin2). Lineage tracing of peri-injury Axin2+ hepatocytes shows that during recovery the injured parenchyma becomes repopulated and repaired by Axin2+ descendants. Using single-cell RNA sequencing, we show that endothelial cells are the major source of Wnts following acute CCl4 toxicity. Induced loss of ß-catenin in peri-injury hepatocytes results in delayed repair and ultimately injury-induced lethality, while loss of Wnt production from endothelial cells leads to a delay in the proliferative response after injury. Conclusion: Our findings highlight the importance of the Wnt/ß-catenin signaling pathway in restoring tissue integrity following acute liver toxicity and establish a role of endothelial cells as an important Wnt-producing regulator of liver tissue repair following localized liver injury.

Axis inhibition protein 1 (Axin1) Deletion-Induced Hepatocarcinogenesis Requires Intact ß-Catenin but Not Notch Cascade in Mice.

Inactivating mutations of axis inhibition protein 1 (AXIN1), a negative regulator of the Wnt/ß-Catenin cascade, are among the common genetic events in human hepatocellular carcinoma (HCC), affecting approximately 10% of cases. In the present manuscript, we sought to define the genetic crosstalk between Axin1 mutants and Wnt/ß-catenin as well as Notch signaling cascades along hepatocarcinogenesis. We discovered that c-MET activation and AXIN1 mutations occur concomitantly in ~3%-5% of human HCC samples. Subsequently, we generated a murine HCC model by means of CRISPR/Cas9-based gene deletion of Axin1 (sgAxin1) in combination with transposon-based expression of c-Met in the mouse liver (c-Met/sgAxin1). Global gene expression analysis of mouse normal liver, HCCs induced by c-Met/sgAxin1, and HCCs induced by c-Met/∆N90-ß-Catenin revealed activation of the Wnt/ß-Catenin and Notch signaling in c-Met/sgAxin1 HCCs. However, only a few of the canonical Wnt/ß-Catenin target genes were induced in c-Met/sgAxin1 HCC when compared with corresponding lesions from c-Met/∆N90-ß-Catenin mice. To study whether endogenous ß-Catenin is required for c-Met/sgAxin1-driven HCC development, we expressed c-Met/sgAxin1 in liver-specific Ctnnb1 null mice, which completely prevented HCC development. Consistently, in AXIN1 mutant or null human HCC cell lines, silencing of ß-Catenin strongly inhibited cell proliferation. In striking contrast, blocking the Notch cascade through expression of either the dominant negative form of the recombinant signal-binding protein for immunoglobulin kappa J region (RBP-J) or the ablation of Notch2 did not significantly affect c-Met/sgAxin1-driven hepatocarcinogenesis. Conclusion: We demonstrated here that loss of Axin1 cooperates with c-Met to induce HCC in mice, in a ß-Catenin signaling-dependent but Notch cascade-independent way.

Hollow Silica Nanoparticles Penetrate the Peripheral Nerve and Enhance the Nerve Blockade from Tetrodotoxin.

The efficacy of tetrodotoxin (TTX), a very potent local anesthetic, is limited by its poor penetration through barriers to axonal surfaces. To address this issue, we encapsulated TTX in hollow silica nanoparticles (TTX-HSN) and injected them at the sciatic nerve in rats. TTX-HSN achieved an increased frequency of successful blocks, prolonged the duration of the block, and decreased the toxicity compared to free TTX. In animals injected with fluorescently labeled HSN, the imaging of frozen sections of nerve demonstrated that HSN could penetrate into nerve and that the penetrating ability of silica nanoparticles was highly size-dependent. These results demonstrated that HSN could deliver TTX into the nerve, enhancing efficacy while improving safety.