Previous research shows that people with depression have elevated levels of the protein SGK1 in their blood. Little is known about this protein, though it seems to influence how brain cells process and transmit information.
To better understand its effects, Christoph Anacker and his colleagues analysed SGK1 in the brains of 50 men after they died, 36 of whom died by suicide. All the men had completed a survey about whether they experienced traumatic events in their childhood, such as abuse, neglect, homelessness or the death of a parent before they turned 16.
The researchers found that in the hippocampus—a brain region involved in stress and memory—levels of genetic material encoding for SGK1 were about 33 per cent higher, on average, in the men who died by suicide than in those who didn’t, rising further among those who also experienced childhood adversity.
In another part of the study, the team looked at more than 8500 children aged 9 to 10 and found that those diagnosed with depression were more likely to have increased activity in genes encoding for SGK1, with this heightened activity also being associated with childhood adversity.
Finally, the researchers gave 10 adult male mice injections of an experimental drug that inhibits SGK1 every day for 10 days. Thirty minutes after each dose, the animals were placed inside a cage with an aggressive mouse for 5 minutes, raising their stress levels. At the end of the 10 days, the injected mice showed fewer signs of anxiety and depression than a separate group of mice that were exposed to an aggressive animal after being injected with saltwater.
“When we reduce levels of SGK1 in this brain region, the hippocampus, mice are more resilient to the effects of stress,” says Anacker. A similar pathway seems to occur in humans, so targeting SGK1 could help alleviate depression among people who have experienced hardships early in life. It isn’t exactly clear how SGK1 may lead to worse mental health, but one explanation is that it interferes with the formation of brain cells in the hippocampus.
The drug used in this study isn’t approved for use in people, but other SGK1 inhibitors are in clinical trials for certain heart conditions. If these prove to be safe, they could be repurposed for mental health conditions, says Anacker. Still, “this kind of basic research in rodents is many, many steps from the kind of evidence that would be needed to say we have an actionable drug target in humans”, says Katie McLaughlin at Harvard University.
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1.1.Which of the following is true about the subjects in the study by Christoph Anacker and his colleagues?
A All subjects were diagnosed with depression.
B More than half of them died by suicide.
C All subjects experienced childhood trauma.
D The study included only female subjects.
解析：选B。1.B细节理解题。根据第二段“...the brains of 50 men... 36 of whom died by suicide.”可知50名男性...其中36人死于自杀。36人超过了50人的一半。故选B。
2.2.What was observed about SGK1 levels in the hippocampus of men who died by suicide?
A Reduced SGK1 protein concentrations.
B Elevated genetic material encoding SGK1.
C No significant change in SGK1.
D Increased SGK1 in blood samples.
解析：选B。2.B细节理解题。原文第三段指出，在海马体中，自杀男性的SGK1编码遗传物质水平平均高出约33%，因此B正确（elevated genetic material encoding SGK1）。A和C与原文相反；D基于第一段血液中的发现，但问题针对海马体。故选B。
3.3.The word “resilient” (as used by Anacker to describe the mice) is closest in meaning to:
A Easily recoverable.
B Physically stronger.
C Genetically adaptable.
D Resistant to stress.
解析：选D。3.D 词义猜测题。原文语境为“老鼠对压力的影响更具韧性”，结合实验过程（注射抑制剂后表现出更少的焦虑和抑郁迹象）可知，“resilient”在此指“对压力有抵抗力”或“能更好地应对压力”，故D最接近。A“容易恢复的”有一定相关性，但不如D直接精准；B“身体更强壮”和C“基因上适应力强”均偏离了该词在文中的心理应激语境。故选D。
4.4.What is a major limitation of this research, as suggested in the text?
A Lack of long-term observation data.
B Exclusion of female subjects entirely.
C Reliance on animal models primarily.
D Overemphasis on genetic factors.
解析：选C。4.C推理判断题。文章最后一段引用了专家Katie McLaughlin的观点，她明确指出“这类在啮齿动物身上的基础研究，距离证明我们在人类身上拥有一个可行的药物靶点还差很多很多步”，这直接点明了该研究的一个主要局限性在于其核心发现依赖于动物模型，距离人类应用尚有巨大距离。因此C正确。B（完全排除女性受试者）在研究中是事实（研究对象为男性和雄性小鼠），但原文中并未将此作为一个局限性提出；A（缺乏长期数据）和D（过分强调遗传因素）在文中均未提及。故选C。
5.5.What is the main focus of the passage?
A SGK1’s link to depression and therapy potential.
B Childhood trauma solely causing depression.
C Mouse models for stress studies.
D SGK1 inhibitors for heart conditions.
解析：选A。5.A 主旨大意题。文章整体讨论了SGK1在抑郁中的作用、童年逆境的影响以及抑制剂的治疗潜力，因此A正确。B太片面；C和D只是文中部分细节，不能概括主旨。故选A。
